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  • richardmitnick 12:15 pm on October 2, 2020 Permalink | Reply
    Tags: , , , , ESOblog   

    From ESOblog: Chilly galactic wind surprises astronomers 

    2 October 2020

    ESO operates the Atacama Pathfinder Experiment, APEX, at one of the highest observatory sites on Earth, at an elevation of 5100 metres, high on the Chajnantor plateau in Chile’s Atacama region.

    Science Snapshots

    Streams of high-speed particles blow out from the centres of galaxies, including our Milky Way, in what is known as the “galactic wind”. Until now, we thought that this galactic wind was mostly made of very hot and diffuse gas with temperatures of millions of degrees. However, a team led by Enrico Di Teodoro of Johns Hopkins University in the USA and The Australian National University has recently detected very cold molecular gas outflowing from the centre of our galaxy for the first time. This surprising and unexplained new discovery could have important implications for the future of the Milky Way.

    After discovering the warm component of the galactic wind, Di Teodoro’s team wanted to go further. “We had often wondered about the possibility of detecting cold molecular gas and the 2017 ESO-Australia agreement finally allowed us to access the unique ESO facilities, including APEX.” says Di Teodoro.

    APEX is the 12-metre Atacama Pathfinder Experiment (APEX) radio telescope that can observe during the day as well as the night.

    The team’s observations revealed carbon monoxide emission in both clouds, which intriguingly had very different properties between them. The further out cloud was moving faster and was more diffuse and more turbulent, suggesting that the cold gas was mixing with its surroundings more, perhaps because it has had more time to interact with them. Alternatively, the differences may be caused by local variations in the hot outflow between the locations of the two clouds.

    “Our exploratory APEX observations actually surprised us, because we did not expect such a large amount of cold molecular gas, based on our current understanding of galactic winds,” explains Di Teodoro.

    Artist’s impression of cold molecular clouds travelling outwards from the Galactic Centre in the galactic wind.
    Credit: NSF/GBO/P.Vosteen.

    “Stars are formed from the collapse of giant clouds of molecular gas, which is exactly the same kind of material that we are observing in the Milky Way’s outflow. This means that our galaxy is expelling the best fuel to form new stars.”

    Fresh gas continuously flows from the external regions of the galaxy towards the inner regions and replenishes this fuel reservoir. However, if the amount of gas flowing in is lower than the amount of gas flowing out in the wind, at some point there will be a shortage of fuel and no new stars will be able to form in the inner galaxy.

    Di Teodoro continues, “If the galactic wind gets stronger in the future, for example if the supermassive black hole increases its level of activity, then this could affect the entire galaxy.”

    How such a large amount of cold gas could be moving at high speed in the galactic wind is puzzling. In the central regions of more active galaxies, cool gas can be accelerated by a very active supermassive black hole or when extraordinarily high numbers of stars form in a “starburst” and eject powerful stellar winds, but neither is the case for the Milky Way. Alternatively, fast-moving cool clouds may be formed when the fast-moving hot wind mixes with slow-moving, cool clouds that are not part of the wind.

    A spectacular new image of the Milky Way has been released to mark the completion of the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL). The APEX telescope in Chile has mapped the full area of the Galactic Plane visible from the southern hemisphere at submillimetre wavelengths — between infrared light and radio waves. This is the sharpest such map yet made, and complements those from recent space-based surveys. The pioneering 12-metre APEX telescope allows astronomers to study the cold Universe: gas and dust only a few tens of degrees above absolute zero. 24 February 2016

    The team targeted two clouds of gas travelling out from the Galactic Centre — which both contain large quantities of hydrogen atoms — to see if they also contain outflowing cold gas. Using APEX, they searched for carbon monoxide, which is commonly found in cold molecular gas clouds. APEX is well suited to the task, thanks to its high sensitivity and ability to map relatively large regions of the sky.

    The APEX telescope, in which ESO is a partner, studies how stars form in our galaxy by observing cold and dusty clouds of molecular gas. By building databases of these large “stellar nurseries”, we can understand how and under what conditions star formation takes place, as well as the large-scale structure of the galaxy. APEX’s location 5100 metres above sea level on the Chajnantor plateau in the dry Atacama Desert in northern Chile provides a unique window to study the Universe in submillimetre light.

    This first detection of outflowing cold molecular gas from the centre of the Milky Way challenges our current theories of how galactic winds form and affect the future evolution of our galaxy. More observations of a larger number of molecular gas clouds are needed to provide a more complete picture of their origin.

     
  • richardmitnick 9:34 am on September 12, 2020 Permalink | Reply
    Tags: "Who’s who on the ELT: part II", , , , , ESOblog   

    From ESOblog: “Who’s who on the ELT: part II” 

    ESO 50 Large

    From ESOblog

    11 September 2020
    People@ESO

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    Bigger than all existing optical research telescopes combined, ESO’s Extremely Large Telescope (ELT) will drive astronomy into the future, tackling the biggest scientific challenges of our time. But to construct such an innovative and powerful telescope, it takes many different people working in an enormous variety of roles. In this series of blog posts, we hear from some of the people working on the ELT, exploring the work they do to help us reach the stars.

    Roberto Tamai (ELT Programme Manager)

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    Roberto Tamai in his office at ESO Headquarters, sitting behind a 3D rendering of the ELT. Credit: ESO/P. Horálek.

    “I see my role as trying to keep the whole ELT team enthusiastic and motivated: we are constructing the biggest highway towards a better understanding of astronomy of our era, and we should all be proud of this, despite the immense difficulties we are overcoming together along the way.

    My workday typically starts at around 06:30, checking emails from colleagues in Chile. Then once in the office (or at my home PC whilst COVID-19 keeps us from the office!), I meet many different people, exchanging with them upon various matters until late in the evening so that I can meet people in ESO Headquarters in Germany, as well as in Chile. Either after that, or between meetings, I proceed with other tasks, such as reading documents, writing reports and preparing presentations.

    I feel so happy when people leave my office with a clear path forward having discussed some difficult situation. But my soul remains that of a mechanical engineer; I have the joy of a young boy when I see hardware working properly, and that of the ELT is gorgeous!

    Sleep is often interspersed with work thoughts and sometimes solutions or memories of unanswered emails! But one of the few situations where I can really unplug from the ELT is when sailing. I also enjoy walks with my wife, reading books, “fixing things at home” or anywhere else, helping my two daughters with their day-to-day tasks, cycling, riding my motorbike or doing sports like tennis, skiing, snorkelling or simply running.”

    Jutta Quentin (Technical Engineering Assistant)

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    Jutta Quentin on a sailing trip in Antarctica. Credit: ESO/Jutta Quentin.

    “Teenager-Jutta once reluctantly accompanied her father to the open house day of the company where he worked as a designer. Rulers, dividers, inkwells, technical pens… they were just as boring as the transparent sheets on large drawing boards. All these strange geometries, countless numbers and weird symbols were more than confusing, but surprisingly, all of this came to life seeing the hardware in the workshops and labs. At the end of the day, she was thrilled — this led to professional training as a Technical Product Designer some years later.

    After several years of experience in industry, most recently in aircraft construction, I literally entered a different world at ESO. Being part of the engineering team that developed the VLT from the very beginning, I learned a lot about the fascinating world of telescopes. Specifically, I was working on the laser guide star facility — sometime later it was incredibly touching to see them beaming into the sky for the first time!

    Now it is time for the ELT — the giant telescope of the future! Such a project consists of countless high-tech components built by different contractors. Assembling them is particularly challenging; after all, it takes place in the Chilean desert! To avoid spatial overlaps and ensure that all subunits fit perfectly it is essential to precisely define the different building volumes and their connection points, and it is my job to create 3D models and drawings of these “design volumes” and “interfaces”. Furthermore I am involved in designing the hardware that will be used at the “first light”. All of this is teamwork and right up to the perfect solution it requires daily discussion. I love it when my virtual components finally become reality and I can touch the hardware — and everything fits!

    Outside of ESO I frequently attend cultural events and with a curiosity to learn about other people, cultures and countries, I love to travel. Particularly impressive were bus tours on my own in Lebanon, Syria and Jordan, trekking tours in Morocco, Kamchatka and Mongolia and a breathtaking sailing trip to Antarctica.”

    Gerd Jakob (Cryogenics Expert)

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    Gerd Jakob with the Land Cruiser — affectionately named “Toyi” — that he uses to travel around Africa.
    Credit: ESO/Gerd Jakob.

    “I am fascinated by the challenges arising simply due to the size of the ELT. Each instrument is about a factor of ten larger than any instrument ESO has ever built before and most of them will be permanently cooled to below -200°C to achieve the best possible sensitivity. I am responsible for the technologies enabling this cryogenic cooling. It is part of my job to find prospective cryogenics and vacuum technologies which will work reliably over the next 20–30 years of ELT operation. This is definitely a new area and it is a great pleasure to be part of a trendsetting team developing something that has never existed before.

    I knew nothing about cryogenics until I had the privilege to work on a spectrometer for ESA’s Infrared Space Observatory, which was tested on the ground at -270°C. I progressed fast in learning by doing, and after a couple of years I was called the expert! I was then assigned as a cryogenics engineer for PACS, a far-infrared camera and spectrometer onboard ESA’s Herschel Space Observatory. The launch of Herschel in May 2009, including a fully functional and deeply cooled PACS at -270°C, was the most memorable moment in my career so far. Hardware built with my own hands, now sent to space, a really great achievement in my life. I believe another most memorable moment is still ahead, when the ELT first light instruments are deeply cooled down to cryogenic temperatures and fully operational at the ELT site.

    When I’m not working on the ELT, you’re likely to find me exploring Africa with my own vehicle. Over the past thirty years I have been there once or twice a year, visiting a total of forty countries. I started with long range trips to the Sahara and some years later I crossed the continent on a long way down to the Cape of Good Hope. The journey is not over yet; in recent years I have been travelling with my car in east Africa, and I am looking forward to the next episodes. Feel free to look up “les amis des girafes” to keep track of my adventures.”

    Juan Carlos González (Lead Systems Engineer)

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    Juan Carlos González at Cerro Armazones in March 2016, just after completing the preparation of the summit (the ELT site). Paranal Observatory — home to ESO’s Very Large Telescope — can be seen in the distant background.Credit: ESO/Juan Carlos González.

    “There have been so many memorable moments working on the ELT that I cannot pick one out as being the most memorable. The opportunity to contribute to the machine that will hopefully allow human beings to get the first clear evidence of life outside Earth, and the opportunity to contribute with my love of engineering, is just incredible.

    As a child, I always liked playing with technical systems, and I still enjoy hobbies related to electronics and controls, so my path has always been clear! As Lead Systems Engineer, I manage a team of 12 people to make sure that the ELT’s science needs are properly converted into engineering requirements at system level, and that these high-level requirements flow down to, and are met by, the subsystems. At the moment, most of the subsystems are in the detailed design phase or even being constructed, so the activity of the systems engineering team mostly focuses on analysing potential changes to the subsystem requirements, as well as defining details that were not covered by the requirements but still need to be discussed and agreed.

    My life isn’t all about engineering though. In my spare time I do some amateur astronomy; I recently bought a small but still powerful enough telescope and have started to explore the night sky. And I like to cycle in the Bavarian countryside when the weather is nice.”

    Christine Bachmaier (Programme Assistant)

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    Christine Bachmaier admiring ESO’s Very Large Telescope during her first visit to Paranal Observatory for the ELT’s first stone ceremony in 2017.Credit: ESO/Christine Bachmaier.

    “I really enjoy working with colleagues from all over the world. It fits with my love of travelling and getting to know other cultures and people; for example, I’ve been on the trail of “Dances with Wolves” in the national parks of North America, and travelled through Sri Lanka, the pearl of the Indian Ocean. My first time in Chile was when I co-organised the ELT’s first stone ceremony, marking the beginning of the construction of the telescope. It was amazing to see the Atacama Desert with its red landscape, watching how the shades and colours change during the day, the blue skies, and then the sunset in the evening. But the most memorable moment was seeing the Milky Way at night. It was such an incredibly fascinating moment. It seemed that I could touch the stars!

    I got in touch with science and engineering for the first time when I joined the ELT team after a year and a half as a human resources assistant at ESO. Working with astronomers and engineers in the ELT team, I am learning a lot, and I find it fascinating. My daily tasks range from organising meetings and trips and dealing with administrative processes, to preparing, following up and managing documents in the ESO data management system. Many unforeseen and short-term changes are the order of the day; I am the contact person for many people in the ELT team, which requires a lot of flexibility but also makes every day different. I am happy to work in this multicultural environment, support my colleagues in getting their daily tasks done, and feel responsible that the secretarial office is running smoothly.”

    Henri Bonnet (Wavefront Architect)

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    Henri Bonnet on his way to the Very Large Telescope’s third Unit Telescope — or Melipal — which means “The Southern Cross” in the indigenous Mapuche language. Credit: ESO/Henri Bonnet.

    “I have an odd job title, but fundamentally my work is to establish a strategy through which the optical performance of the ELT can be controlled and to establish a path to reaching that point. I provide some of the simulation tools used by the system engineering team to monitor the impact of changes in the design of the ELT. I’m also part of the team preparing for the commissioning of the telescope — the period after the telescope is up and running, when it is being tested and verified to ensure that everything works as it should and that any small last minute issues are resolved. My days are spent working on the system that will correct for the turbulence in Earth’s atmosphere that blurs light from the Universe. I simulate the system on a computer, experiment with elements of it using an optical test bench, discuss with colleagues, and document algorithms.

    When I was young, I liked physics but never felt that I had the curiosity to become a research physicist. Following a rather chaotic education and career path, I feel fortunate to have ended up in this discipline, which combines physics and maths in an experimental field

    I enjoy learning from the few of our senior colleagues who have already built an observatory. Our collective experience and expertise is a significant component of the knowledge base of the ELT team, and these colleagues help us prepare for the commissioning as well as we can. The true challenges will of course be discovered in the field, but I like the spirit of adventure that comes with that. It is difficult to admit that I may be too old to be part of the ELT commissioning, but I like the idea that I am working for the next generation.”

    Stefano Stanghellini (Dome and Telescope Structure Project Manager)

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    Stefano Stanghellini at Cerro Armazones site where the ELT is being constructed. The photo was taken on the occasion of the first stone ceremony in May 2017. Credit: ESO/Stefano Stanghellini.

    “I remember the first time that the primary mirror of the VLT was mounted in its mirror cell on Easter 1998. Everybody was very anxious because nobody had ever handled such a thin and delicate mirror. The mirror is attached to the mirror cell with more than 220 interface points, and all of these have to work precisely together without ever structurally stressing the mirror. There was a lot of trepidation, but thanks to the extensive studies performed and the tests done with a dummy mirror, all worked fine in the end, and the VLT became the breathtaking machine that we know today. As for the ELT, we are still in the construction phase — although the onsite excavation and the preparation of the foundations are just finishing — and the most visible achievements will be in the near future. However, the start of the procurement contract for the dome and main structure (DMS) to which I was assigned after the end of the construction of the ALMA antennas — which marked the official start of construction of the ELT — was a remarkable achievement that involved the efforts of so many.

    I am responsible for following this contract, which is the largest ever signed in ground-based astronomy and involves many technical disciplines and commercial aspects. I collaborate with a large group of ESO colleagues involved in following the procurement of the DMS and ensuring its success. Success means completing the contract whilst respecting the demanding technical specifications of the DMS, the scientific requirements of the ELT, and the allocated budget and schedule.

    Engineering can be found in almost everything. I actually started my career in nuclear plants and afterwards in the aircraft industry, but I got to know ESO and applied for an engineering position on the VLT, specifically in the delicate mechanics for its optical system. One may become very curious exploring new fields, and the work at ESO was accompanied by this curiosity. Today the thing I like most is to work in engineering of complex systems, where many contrasting requirements have to be combined to create the best possible final product.

    I really enjoy putting my efforts into realising a state-of-the-art telescope that will hopefully enable discoveries for generations. I am also happy to see that thanks to the efforts of many, including me, this telescope — or better, this observatory — is being built and is progressing. The construction in Chile, which started just over two years ago, is fascinating and it will be amazing to see the progress of the erection of this gigantic dome and telescope.”

    Jimmy Arancibia (Civil Engineer)

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    Jimmy Arancibia at the site of the ELT Armazones Top Platform, where the telescope dome and auxiliary buildings are currently being built. Credit: ESO/Jimmy Arancibia.

    “Construction has always been one of my interests; for me, it is about materialising somebody else’s dream. I was one of the first people to arrive at the site of the ALMA Observatory in 2001. We started with exploring the site and planning the roads, then began constructing the antenna foundations located more than 5000 metres above sea level. Afterwards, we constructed the technical buildings and the residence for astronomers. These were some of the most memorable moments of my career and allowed me to greatly expand my experience in the field of engineering and construction.

    Now being part of the construction of the largest telescope in the world is something that really excites me as I am passionate about astronomy. My role is to review the technical documents sent in by the construction contractor, verify that they comply with building regulations, then verify in the field that requirements are being fulfilled. One of my biggest personal achievements so far on the ELT was designing and building the Technical Facility, where the ELT’s many mirrors will be cleaned and coated.”

    See the full article here .


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    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo.

    Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT, a major asset of the Adaptive Optics system.

    ESO VLT 4 lasers on Yepun.

    Part of ESO’s Paranal Observatory, the VLT Survey Telescope (VISTA) observes the brilliantly clear skies above the Atacama Desert of Chile. It is the largest survey telescope in the world in visible light at an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO/Cerro LaSilla, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres.

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).

    ESO/MPIfR APEX high on the Chajnantor plateau in Chile’s Atacama region, at an altitude of over 4,800 m (15,700 ft).

    A novel gamma ray telescope under construction on Mount Hopkins, Arizona. a large project known as the Čerenkov Telescope Array, composed of hundreds of similar telescopes to be situated in the Canary Islands and Chile. The telescope on Mount Hopkins will be fitted with a prototype high-speed camera, assembled at the University of Wisconsin–Madison, and capable of taking pictures at a billion frames per second. Credit: Vladimir Vassiliev.

     
  • richardmitnick 5:05 pm on July 26, 2020 Permalink | Reply
    Tags: "How old are the stars?", Accurately measuring the ages of the stars is the missing piece in the puzzle of Galactic archaeology that would help us understand how the Milky Way formed and evolved., , , , Chemical clocks, , , , ESOblog, Giada Casali, HARPS instrument on the ESO 3.6-metre telescope, Isochrone fitting method, , Laura Magrini, , The Gaia-ESO survey is the largest public spectroscopic survey (it used the Very Large Telescope (VLT) for over 300 nights!) carried out on an eight-metre-diameter telescope.   

    From ESOblog: “How old are the stars?” 

    ESO 50 Large

    From ESOblog

    24 July 2020

    1
    Science Snapshots

    2
    Giada Casali and Laura Magrini

    It’s one of the biggest challenges in astrophysics: accurately measuring the ages of the stars is the missing piece in the puzzle of Galactic archaeology that would help us understand how the Milky Way formed and evolved. Scientists have started using the novel “chemical clocks” method to measure the ages of stars close to the Sun, but a team of astronomers recently used data from ESO telescopes to discover that the situation becomes much more complicated when we move outside our solar neighbourhood. We find out more from the scientists who led the research.

    Q. Firstly, what exactly do you mean when you talk about “chemical clocks”?

    Giada Casali (GC): When we talk about chemical clocks, we are referring to the ratios between particular pairs of elements — called chemical abundance ratios — in a star, that display a strong dependence on age. Every star is made up of lots of different elements that are produced in different processes and at different time scales, which is why we can use them as an innovative way to measure a star’s age.

    Laura Magrini (LM): For example, massive stars produce some elements quickly, whereas smaller stars produce them more slowly. So in theory, by looking at the spectrum of light from a star and measuring the abundance ratio between an element produced very quickly (when the Galaxy was very young) and an element produced much more slowly (and therefore only produced recently), we have a sort of track of when a star formed, and can therefore predict its age. Using stars located very close to the Sun, astronomers have discovered relations between age and some specific age-dependent abundance ratios. But we wanted to know: Are these relations universal? Can they be applied to all the stars in our Galaxy?

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    In April 2015 the HARPS laser frequency comb was installed on the HARPS planet-finding instrument on the ESO 3.6-metre telescope at the La Silla Observatory in Chile after completion of an intense first commissioning phase. The increase in accuracy made possible by this new installation should in future allow HARPS to be able to detect Earth-mass planets in Earth-like orbits around other stars for the first time. Credit ESO.

    ESO/HARPS at La Silla


    ESO 3.6m telescope & HARPS at Cerro LaSilla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    This picture shows a HARPS spectrum of the light from the two laser frequency combs that that were tested. Credit: ESO.

    Q. Could you summarise what you found in this research [Astronomy and Astrophysics] ?

    LM: Our idea, matured with Lorenzo Spina at Monash University in Australia, was to use archival data from the HARPS instrument on the ESO 3.6-metre telescope to measure specific chemical clocks in stars similar to the Sun, but with different abundances of elements heavier than helium and hydrogen. When we say “similar to the Sun”, we mean stars with very similar surface temperature and surface gravity and we call them solar-like stars; selecting such stars means that any variation in their spectrum of light is due to differences in chemical abundances, which we can presume are related only to their age.

    GC: We compared the ages of the solar-like stars, calculated due to their very well-known properties, with the ratios of specific elements, for example yttrium to magnesium, which is particularly strongly dependent on age. We were expecting to be able to apply our relation everywhere, but when we looked at the yttrium to magnesium ratio in stars further away from the Sun, in the direction of the Galactic centre, we found less yttrium than we would expect to find in stars of the same age close to the Sun. This means that this specific chemical clock relationship doesn’t apply in the same way everywhere in the Milky Way!

    Q. Were you surprised by this discovery?

    LM: Absolutely! Previous studies gave us hope that there may be a universal relationship between chemical clocks and age for solar-like stars throughout the Milky Way, but we found that this relationship can’t be applied everywhere. We think the difference arises because the stars didn’t all form at the same time, rather the Galaxy formed “inside out”, with the inner parts forming the quickest. This means that the star formation process varies throughout the Galaxy and the contribution of low and high mass stars with varying amounts of heavy elements is different in different places and at different epochs.

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    A Hertzsprung-Russell diagram for open clusters observed with the European Space Agency’s Gaia mission, plotted over an image of open cluster NGC 3293. Credit: Gaia data – ESA/Gaia/DPAC, Carine Babusiaux and co-authors of the paper Gaia Data Release 2: Observational Hertzsprung-Russell diagrams; Credit NGC 3293 – ESO/G. Beccari; Credit graphic design – R. Spiga (INAF)

    ESA/GAIA satellite

    The x axis shows the colour of stars in open clusters, and the y axis shows their apparent brightness as seen from Earth.

    Q. So why did you decide to carry out this research in the first place?

    GC: We wanted to investigate another method to date stars. Determining stellar ages is really important for astronomers to understand how the Milky Way formed and evolved, but it’s actually one of the most difficult parts of astrophysics. The most common technique used at the moment is called isochrone fitting; this technique compares the observed colours and brightnesses of stars with the expected ones from theoretical predictions, and from that comparison it infers the ages of the stars.

    The technique works very well for groups of stars all of the same age, for example members of star clusters. However, it is very difficult to use it to date individual stars, unless their properties are particularly well known. For solar-like stars, we do know their properties, so we can calibrate the new chemical clock method with the isochrone fitting method to find a new way to date stars with unknown properties.

    LM: Our idea was to find a universal relation, valid across the entire Milky Way, that would allow us to measure stellar ages simply by measuring their chemical composition…but life is always more complicated! In the past, we looked specifically at the abundance between carbon and nitrogen, which is a very effective method of figuring out the ages of giant stars. We found that since this abundance ratio essentially depends on stellar evolution, it is effectively valid across the entire Galactic disc, while it can vary, for instance, in the Galactic halo.

    Caterpillar Project A Milky-Way-size dark-matter halo and its subhalos circled, an enormous suite of simulations . Griffen et al. 2016

    Our ultimate aim is to collect different chemical relations for many stars that we know the ages of. The Gaia-ESO survey — which we used for both pieces of research — is the largest public spectroscopic survey (it used the Very Large Telescope (VLT) for over 300 nights!) carried out on an eight-metre-diameter telescope. It provides the most accurate database of detailed chemical abundances in stars across all the components of the Galaxy, and is also the only one focusing on star clusters, sampling all stars from young to old. The Gaia-ESO survey, therefore, is a fundamental tool for our research.

    Q. What are the implications of this discovery?

    LM: The result means that astronomers need to be more careful when they are trying to work out the ages of stars, as it is not as simple as we had previously assumed. We applied the relationships we found for different pairs of chemical elements in the HARPS data for nearby stars to open star clusters observed in the Gaia-ESO survey, and found that our relationship, built for the solar neighbourhood, does not correctly calculate the ages of stars in clusters in the Milky Way’s inner disc, where star formation and evolution happens much faster.

    We know that the Milky Way is made up of two discs of stars — one thin and one thick. Recent results from the European Space Agency’s Gaia satellite show that the thick disc probably formed through the interaction of the Milky Way with another galaxy several billion years ago, and that the stars in each disc have different ages. It is known that the stars in the thick disc contain much more magnesium than iron, for example, suggesting a different star formation history. Using our chemical clock relations, we were able to confirm the difference in ages of the two discs for stars located close to the Sun.

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    The anatomy of the Milky Way.
    Left: NASA/JPL Caltech, R Hurt; Right: ESA, Layout: ESA/ATG Medialab

    Q. Why do you think is it important to measure the ages of stars and understand the formation and the evolution of the Milky Way?

    LM: The only place that we can measure the ages of individual stars so precisely is the Milky Way. So by investigating these stars in more detail, we can better understand spiral galaxies, which are among the most common — and for me the most beautiful — type of galaxies in the Universe. As the luminous part of the Universe, galaxies are our “window” to understanding the Universe’s evolution; they are vital for understanding how it formed and evolved, and what its future could hold.

    Q. Do you plan to follow up this research in any way?

    GC: We want to dig deeper into the relationship between various chemical abundance ratios and distance from the centre of the Milky Way using open star clusters as a calibrator. In particular we will continue to use data from the Gaia-ESO survey and APOGEE.

    LM: In just a few years, the Extremely Large Telescope (ELT) will be up and running, and will allow us to resolve stars — and obtain their individual light spectra — in other galaxies with a similar detail to what we can now achieve only in the Milky Way. The ELT will be able to look at individual stars in other galaxies in our Local Group, and in the Virgo cluster of galaxies, so that we can measure their chemical composition and extend our studies to different environments.

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    Seen from the southern skies, the Large and Small Magellanic Clouds (the LMC and SMC, respectively) are bright patches in the sky. These two irregular dwarf galaxies, together with our Milky Way Galaxy, belong to the so-called Local Group of galaxies.

    Local Group. Andrew Z. Colvin 3 March 2011

    Astronomers once thought that the two Magellanic Clouds orbited the Milky Way, but recent research suggests this is not the case, and that they are in fact on their first pass by the Milky Way.

    The LMC, lying at a distance of 160 000 light-years, and its neighbour the SMC, some 200,000 light-years away, are among the largest distant objects we can observe with the unaided eye. Both galaxies have notable bar features across their central discs, although the very strong tidal forces exerted by the Milky Way have distorted the galaxies considerably. The mutual gravitational pull of the three interacting galaxies has drawn out long streams of neutral hydrogen that interlink the three galaxies.

    Magellanic Bridge ESA Gaia satellite. Image credit V. Belokurov D. Erkal A. Mellinger.

    On 23 February 1987 the LMC hosted a dramatic cosmic explosion when a supernova (SN 1987A) ignited near the Tarantula Nebula. SN 1987A ranks among the brightest and closest events of this kind ever observed in recorded history.

    SN 1987A remnant, imaged by ALMA. The inner region is contrasted with the outer shell, lacy white and blue circles, where the blast wave from the supernova is colliding with the envelope of gas ejected from the star prior to its powerful detonation. Image credit: ALMA / ESO / NAOJ / NRAO / Alexandra Angelich, NRAO / AUI / NSF.

    Al Sufi, the Persian astronomer, described the LMC for the first time in his Book of Fixed Stars in AD 964. He called it Al Bakr, describing it as the White Ox of southern Arabia. Referred to in some older books as Nubecula Major and Minor, the Clouds take their modern name from the explorer Ferdinand Magellan, who first recorded their existence on his voyage of circumnavigation in 1519–22, and brought news of them to Europe; although a letter written by Amerigo Vespucci during his third voyage about 1503–4 may refer to them indirectly. Credit: ESO/S. Brunier

    Biography Giada Casali and Laura Magrini

    Giada Casali is a PhD student in her final year at the University of Florence/INAF-Astrophysical Observatory of Arcetri (Italy). She obtained her bachelor’s and master’s degrees at the University of Pisa (Italy). Giada has been working in the field of galactic archaeology, combining data collected by the European Space Agency’s Gaia satellite and ground-based large spectroscopic surveys. Her expertise mainly focuses on stellar spectroscopy and the determination of stellar ages.

    Laura Magrini obtained her PhD in 2003 at the University of Florence (Italy), in collaboration with the Instituto de Astronomía de Canarias (Spain). After several postdoctoral positions in the field of galactic archaeology, since 2012 she has worked as a researcher at the INAF-Astrophysical Observatory of Arcetri. She works on galaxy formation and evolution, using spectroscopic data of stellar populations in the Milky Way and nearby galaxies.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Visit ESO in Social Media-

    Facebook

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    ESO Bloc Icon

    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

    Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT, a major asset of the Adaptive Optics system


    ESO LaSilla
    ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT 4 lasers on Yepun


    ESO Vista Telescope
    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO NTT
    ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT Survey telescope
    VLT Survey Telescope at Cerro Paranal with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


    ESO APEXESO/MPIfR APEX high on the Chajnantor plateau in Chile’s Atacama region, at an altitude of over 4,800 m (15,700 ft)at the Llano de Chajnantor Observatory in the Atacama desert.

    A novel gamma ray telescope under construction on Mount Hopkins, Arizona. a large project known as the Cherenkov Telescope Array, composed of hundreds of similar telescopes to be situated in the Canary Islands and Chile. The telescope on Mount Hopkins will be fitted with a prototype high-speed camera, assembled at the University of Wisconsin–Madison, and capable of taking pictures at a billion frames per second. Credit: Vladimir Vassiliev

     
  • richardmitnick 10:06 am on July 11, 2020 Permalink | Reply
    Tags: "The behemoth behind the brightness", , , , , Christopher Onken, , ESOblog, Fuyan Bian   

    From ESOblog: “The behemoth behind the brightness” 

    ESO 50 Large

    From ESOblog

    1
    Christopher Onken

    2
    Fuyan Bian

    3
    Finding one of the biggest black holes in the Universe powering the brightest quasar ever detected.

    10 July 2020
    Science@ESO

    Two years ago a team of astronomers used Australian telescopes to accurately image a distant quasar that was subsequently revealed to be the most luminous ever detected. A quasar is a bright object at the centre of a galaxy, in which a supermassive black hole is feeding on matter falling into it from a surrounding disk of gas. Revisiting the colossal quasar with ESO’s Very Large Telescope, the team has revealed another staggering feat: it is powered by the most massive black hole ever found in the early Universe. We speak to team members Christopher Onken and Fuyan Bian to find out more.

    Q. Your team expanded on research from nearly two years ago when you discovered the brightest quasar ever. What did you find this time?

    Fuyan Bian (FB): What we found two years ago was the most luminous quasar astronomers have discovered so far at over 10^14 (100 000 000 000 000!) times brighter than the Sun. For this follow-up research, we carried out extensive observations of the object using the VLT and Keck Observatory.

    This quasar lies at the centre of a galaxy, and hot gas from its host galaxy is actively falling onto this central supermassive black hole, forming a brightly shining accretion disc around the black hole that astronomers call a quasar. The purpose of our follow-up observations was to view this hot gas in much higher detail to measure the mass of the supermassive black hole.

    Christopher Onken (CO): We knew from our initial study that this quasar has a very high redshift, meaning it is very distant, and therefore the light left it long ago when the Universe was very young. In the latest research, we found that the quasar is powered by a black hole 34 billion times the mass of the Sun, making it the most massive black hole found in the early Universe and one of the biggest ever detected. This object has a mass of about half of all the stars in the Milky Way condensed into the space that doesn’t even stretch 1% of the distance between the Sun and the nearest star.


    Artist’s impression of the Black Hole at the heart of Messier 87. Credit: ESO/M. Kornmesser

    Messier 87*, The first image of a black hole. This is the supermassive black hole at the center of the galaxy Messier 87. Image via JPL/ Event Horizon Telescope Collaboration.

    Q. So what exactly is a supermassive black hole, and how is this one different from others found in the past?

    FB: There are many types of black holes with quite different evolutionary histories. Primordial black holes are very small and are still only predicted by theory; they’ve never been observed. Stellar black holes form from the last phase of a massive star exploding as a supernova.

    CO: Higher in mass still we see supermassive black holes. With around 20 years of experience studying these objects we have found that every reasonably large galaxy has a black hole at its centre, ranging from a hundred thousand to a few billion times the mass of the Sun. What’s interesting is that the black hole we found looks in all other aspects just like an ordinary black hole powering a quasar; it’s really only its extraordinary mass that sets it apart.

    Q. Do you know how something this big formed?

    CO: The basic answer is that we just don’t know definitively how these objects form.The growth of a black hole is a self-limiting process. They grow as surrounding matter in the accretion disc falls into them. However, the more they grow, the more light and radiation pressure the quasar produces, pushing away the feeding gas from around the black hole, slowing the progression of falling matter. So there is a limit to how fast black holes can grow.

    In the case of particularly massive black holes, we are unsure if they started off being large when they initially formed or if they grew in some other way that the unusual conditions of the early Universe could have allowed for. There are various theories and ideas but this is something that we just don’t have a good enough understanding of yet.

    FB: We tend to find these types of black holes at the early epoch of the Universe when the first galaxies were still forming. One theory for how they formed suggests that they started small, forming from black hole “seeds”’ during this early period, growing larger and larger to the point at which they are observable. The size of this black hole suggests the “seed” needed to be quite massive to let this black hole become so large in such a short period of time.

    Q: How did you both feel when you realised the extraordinary mass of this black hole?

    FB: I remember it really well. I remember putting the numbers from my measurements into my computer code and clicking the button and thinking, “oh wow this is actually very massive!” We had predicted that this black hole would be large, but we didn’t know exactly how large. We realised only later that it was one of the largest ever found when checking with one of our collaborators. It definitely felt as if all the hard work paid off.

    CO: Initially I was mostly worried about how reliable our estimate was. Once we had convinced ourselves that we did everything right and there weren’t any other strange explanations for our measurement it was quite amazing to think about.

    Q. Why do you think it is important to study bright quasars and massive black holes?

    FB: The largest black holes likely started to form around 100 million years after the Big Bang. The new data helps us understand the formation process for black holes as big as this one during this very early time period, and discover what the environment must have been like for something this big to have formed. It also tells us about how the first generation of stars formed in such an extreme environment, which is certainly very different from our Milky Way.

    CO: Most supermassive black holes we find are in the nearby Universe. This is one of just a few we have identified that is located far away, at a time where the Universe is only around 1.25 billion years old. In the nearby Universe we find that the mass of a quasar is mainly proportionate to the mass of its host galaxy, but we don’t have nearly enough data to conclude this relation in the early Universe.

    The hope is that by looking at these extreme early cases, even if our measurements have a bit of uncertainty in them, we can construct a clear enough picture to see if this relationship still holds true, that the galaxy is indeed also incredibly massive, growing at the same pace as the black hole.

    2
    SkyMapper Southern Sky Survey image of the brightest quasar ever detected (the faint red dot in the middle). This image is about five arcminutes on each side.

    In future research we plan to use ALMA [below] to measure the cold gas within quasar host galaxies to find their mass as well. Hopefully we can uncover some clues about the relationship and physical processes that link quasars with host galaxies, revealing the properties of early galaxies themselves.

    Q. You originally used data from survey telescopes to look at this object, then used spectroscopic instruments including X-shooter on the VLT [below]. Why were further observations with spectroscopic instruments needed?

    ESO X-shooter on VLT on UT2 at Cerro Paranal, Chile

    FB: The survey telescopes we used measure only the amount of total amount og light emitted by an object, so we used them to pick quasar candidates to observe in more detail, but their results are not actually very useful for detailed studies. For this, we have to use large, precise spectroscopic telescopes like the VLT.

    CO: Indeed; the data from the Australian survey telescopes that we used only allow us to distinguish the quasars from stars in our own galaxy. In order to conduct “spectroscopic analysis” and really nail down the mass of these objects, we needed specialised equipment like the X-shooter spectrograph that splits light up into a spectrum of wavelengths.

    Q. Can you explain in more detail how you used X-shooter to find the black hole’s mass?

    CO: There are two key things you need to measure to estimate a black hole’s mass in this way. You need to figure out how fast the gas orbiting the black hole is moving and how far away from the black hole the gas is sitting. We measured the velocity of the gas by analysing a specific emission line on the spectrum of light coming from the quasar — the MgII doublet emission line. This singled out the light emitted by ionised magnesium near the black hole. The width of this line on a spectrum directly tells us how fast the gas is spinning around the central black hole.

    FB: The X-shooter instrument has a wide enough coverage and resolution to give us an accurate measurement of both of these values — the velocity of the gas and its distance from the black hole — allowing us to weigh a black hole from billions of light years away.

    Q. Why did you choose to use the VLT for your extra research? What benefit did this bring over other spectroscopic telescopes in Australia?

    CO: Two main reasons. The first is that the VLT is much larger than any telescope in Australia. Secondly, the VLT’s X-shooter instrument is really unique in the world, and certainly unique in the facilities that Australia has access to. It is the best in the world for this particular kind of work, with very high wavelength coverage and high spectral resolution, making it perfect for our specific research where we wanted to clearly distinguish the magnesium lines we were after.

    Q. How was the strategic partnership between ESO and Australia beneficial to your research?

    FB: I moved to ESO in 2018, the same year that Australia became a strategic partner with ESO. Teaming up with researchers from Australia was an opportunity for my research where I can contribute my expertise, observation experience and project design with the Australian team. A good combination and opportunity for us both.

    CO: It’s great because it lets us do the science that we want to do. There’s really nothing local in Australia that can make the precise measurements that we wanted for this research. As a partner of ESO, we can use these world-leading instruments and facilities that also cover the southern sky. ESO instruments give us an opportunity to make fantastically detailed observations, including follow-ups to what we can observe using local telescopes. It’s more than what we could have asked for having access to these extra facilities.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Bloc Icon

    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

    Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT, a major asset of the Adaptive Optics system


    ESO LaSilla
    ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT 4 lasers on Yepun


    ESO Vista Telescope
    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO NTT
    ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT Survey telescope
    VLT Survey Telescope at Cerro Paranal with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


    ESO APEXESO/MPIfR APEX high on the Chajnantor plateau in Chile’s Atacama region, at an altitude of over 4,800 m (15,700 ft)at the Llano de Chajnantor Observatory in the Atacama desert.

    A novel gamma ray telescope under construction on Mount Hopkins, Arizona. a large project known as the Cherenkov Telescope Array, composed of hundreds of similar telescopes to be situated in the Canary Islands and Chile. The telescope on Mount Hopkins will be fitted with a prototype high-speed camera, assembled at the University of Wisconsin–Madison, and capable of taking pictures at a billion frames per second. Credit: Vladimir Vassiliev

     
  • richardmitnick 8:47 am on June 26, 2020 Permalink | Reply
    Tags: "How the VLT came to pass", , , , , ESOblog   

    From ESOblog: “How the VLT came to pass” 

    ESO 50 Large

    From ESOblog

    26 June 2020
    People@ESO

    Observing infrared light from the Universe reveals objects that are difficult or impossible to see in other types of light. In particular, infrared astronomy is useful for exploring cool, dusty places such as star-forming regions, as well as cold exoplanets, comets and asteroids. ESO’s Very Large Telescope (VLT) [below] is one of humanity’s major telescopes for observing in infrared, but because of the technical challenges linked to this relatively new area of astronomy, it initially faced a lot of unknowns and experimental difficulties. In this blog post, we speak to Pierre Léna, a French astrophysicist who was instrumental in the design of the VLT, ensuring its use as an infrared telescope to observe the Universe in unprecedented detail using adaptive optics and interferometry.

    4
    Pierre Léna

    2009 ESO VLTI Interferometer image, Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level, • ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).

    2
    A tour through the Atacama Desert in 1999. From left to right the photo shows retired ESO Director General Lodewijk Woltjer, incoming (from 1 September 1999) Director General Catherine Cesarsky, Michel Dennefeld, Pierre Léna, and Gustav Tammann. Credit: ESO/P. Lena.

    Q. You started studying astronomy in the late 1950s, when infrared astronomy was hardly conceivable. What first piqued your interest in astronomy, and how did you become a professional astronomer?

    A. My relationship with astronomy is probably similar to that of many of my colleagues. My curiosity began at a very young age, at six or seven. The mystery of the stars and the phases of the Moon attracted me enormously. I had an infinite curiosity for nature, for light, for the colours of butterflies and beetles. All this seemed mysterious, full of attraction, full of questions that I could not even formulate for myself, let alone for an adult.

    My father, a self-taught man, was very curious about science, and the construction of my first telescope, which followed the microscope he had given me, fascinated him. Then in high school, the discovery of physics and mathematics excited me. At the time, to pass the high school exams, the mathematics course taught cosmography, an elementary celestial mechanics, but also the basics of astrophysics. While still in high school, I discovered the Société Astronomique de France. Joining amateur astronomers in its small observatory, I observed the sky every Thursday night. At that time, the Paris night sky had fewer stray lights, but more aerosols than today, and terrible seeing.

    In high school, we created an astronomy club. We built small refractors with achromatic objective lenses recovered from German submarine periscopes and sold in Paris. But most of all, with my small refractor, I loved summer nights at our holiday home in Burgundy, far from the city lights. There, I would travel through the sky and its nebulae. Physics attracted me by its precision, the beauty of its experiments — which I willingly repeated at home — and the mathematical tools that made it so precise, so I devoted my higher education to it.

    I started my first research project at the Haute-Provence Observatory.

    Haute-Provence Observatory 1.93 meter telescope interior

    Haute-Provence Observatory, in the southeast of France, about 90 km east of Avignon and 100 km north of Marseille,Altitude 650 m (2,130 ft),

    There, during a whole summer, I was introduced to the mysteries of Fourier spectroscopy. In 1960, I obtained my Agrégation in physics, which qualified me to become a high school teacher, but also to begin preparing a doctorate. Passionate about teaching, I immediately obtained a position at the Sorbonne, in the new modern campus that was opening south of Paris (Orsay). I hesitated for a while, suffering from serious health problems, before really getting involved in research.

    Q. Then you became fascinated by infrared astronomy. Why did you become interested in this area of astronomy, and how have you seen it advance throughout your career?

    A. In 1958, de Gaulle, Head of the French government and soon to be President of the French Republic, asked two eminent scientists for a report on the future of space research. Regarding astronomy, this report focused on the two spectral domains that seemed accessible as soon as instruments could go into space: ultraviolet and infrared. I was one of the few young researchers who got involved in the second field, which was infinitely more difficult. Hardly any measurements or spectra existed of infrared radiation except from the Sun and Mars and the experimental difficulty was also considerable. The British military use of infrared detection during the war had led to some progress, but the detectors, operating at room temperature, were deplorably unsensitive and, moreover, consisted of only a single pixel. Obtaining an image was therefore a hazardous experimental venture.

    The four decades that followed were punctuated by successive advances on these limitations, which improved detection sensitivity by a factor of more than a billion and multiplied the number of pixels in the cameras by more than a million. These advances required instruments to work at increasingly lower temperatures, first cooled with liquid nitrogen, then with liquid helium, and even with helium-3. The difficulties did not stop there. A lot of near-infrared radiation is absorbed by Earth’s atmosphere. As for the far-infrared, the atmosphere is totally opaque to it. The need to place telescopes on high mountains, then on board aircraft, stratospheric balloon-borne nacelles, rockets and later in space added to the difficulties.

    Q. So how did you personally contribute to developing and implementing instruments that could carry out infrared astronomy?

    A. I have been an actor or user of each of these steps in the discovery of the immense and fertile field of infrared astronomy. Between 1966 and 1969, I began grappling with the determination, by observation, of the variation in brightness between the centre and edge of the solar disc in the near- and mid-infrared, to improve the model of the Sun’s atmosphere. The McMath-Pierce Solar Telescope at Kitt Peak Observatory, Arizona, was the only telescope with sufficient altitude and spatial resolution in the near-infrared.

    McMath-Pierce Solar Telescope at Kitt Peak National Observatory in Arizona, USA

    Kitt Peak National Observatory of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono O’odham Nation, 88 kilometers 55 mi west-southwest of Tucson, Arizona, Altitude 2,096 m (6,877 ft)

    When it appeared necessary to complete these measurements with photometry of the Sun in the far infrared I used NASA’s CV-990 Galileo-I aircraft. A stay of a few months at the High Altitude Observatory in Boulder, Colorado, allowed us to install a Fourier spectrometer on the aircraft and obtain the necessary measurements, made in the stratosphere. I then had all the material to defend my Doctorat d’Etat in 1969 when I returned to France.

    What to do next? I was very sceptical about using stratospheric balloons for infrared astronomy, which were unreliable without considerable resources. In the Paris Observatory, I formed a team to install an infrared telescope onboard a Caravelle aircraft — much more reliable indeed — that flew for several years in the northern and southern hemispheres and accumulated observations in the far infrared. We learned the trade, we could establish a fructuous cooperation over Europe, and make ‘infrared friends’ in the UK, Germany, the Netherlands and Sweden, who were building and flying with us. The young European Space Agency had us participate in Space Shuttle simulation missions with our telescope installed on a NASA aircraft. Infrared astronomy was beginning to be tamed.

    Q. This led to you playing a big part in the conception of ESO’s Very Large Telescope (VLT). How exactly were you involved?

    A. My relationship with ESO began in 1977 when I was appointed as a member of ESO’s Scientific Technical Committee (STC), and then as its president the following year. Faced with the financial difficulties of maintaining an airborne astronomical programme in the long term, I decided to change my research trajectory towards near-infrared interferometry, since with a large telescope the resolution achieved by beating the seeing would make it possible to resolve dim objects such as forming stars or the energetic active nuclei of galaxies. Using a novel revolutionary technique called “speckle interferometry”, a very simple instrument was installed first on the Mayall 4-meter telescope at Kitt Peak, then on the ESO 3.6-metre telescope at La Silla Observatory. It was quickly productive. Chairing the STC and observing at La Silla, I got to know and enjoy ESO, its then director Lo Woltjer, and its staff in Chile.

    NOAO Mayall 4 m telescope interior


    NOAO/Mayall 4 m telescope at Kitt Peak, Arizona, USA, Altitude 2,120 m (6,960 ft)

    ESO 3.6m telescope & HARPS at Cerro LaSilla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    The prospect of a European telescope with a surface area equivalent to that of an instrument with a diameter of 16 metres, to succeed the La Silla facilities was raised in 1977. In the following years, in addition to equipping the ESO 3.6-metre telescope with instruments and commissioning ESO’s New Technology Telescope [below], the STC naturally became involved in this new project, which eventually became the VLT. The operation of this telescope as an optical interferometer had not been taken very seriously by many astronomers, but Lo Woltjer, always attentive to new developments, accepted my proposal to organise a conference at ESO Headquarters in Germany in 1981 on the scientific importance of high angular resolution in infrared and visible wavelengths. Soon after, ESO set up a working group to explore the feasibility of an interferometric mode for this future telescope. Should this be really feasible and succeed, the scientific harvest we could forecast was already outstanding. Thirty years later, reality has taken it far beyond our most dreamy expectations! These were incredibly exciting years that culminated in December 1987, when the interferometric mode of the VLT, including adaptive optics, was approved as an integral part of the project. I have described the details of this at length in my book Une Histoire de flou.


    The VLT uses a technique called interferometry to combine light from two or more telescopes, allowing them to act as a single unit with a mirror diameter equivalent, as far as image resolution is concerned, to the distance between the telescopes.Credit: ESO.

    Q. You were then Scientific Representative of France to the ESO Council from 1986 to 1993. What exactly does this role involve and how did you continue to advocate for the VLT?

    A. I was appointed by France to the ESO Council shortly before the official approval of the VLT. For each of the eight states that were members of ESO at that time, two representatives sat on the Council, one a scientist and the other a diplomat. Being on the Council swung me over to scientific policy, financial issues and sometimes to politics in general. The dictatorship in Chile, for example, posed all kinds of challenges for the functioning of ESO until the country’s return to democracy in 1990.

    I was convinced that the future of research lay in a European organisation with minimal bureaucracy, and this was offered by the founding treaty of ESO, which I could observe working so well. I appreciated the complementarity of styles, characters and personalities within the Council between different nationalities and I admired the management style of the Director General Lo Woltjer. This period was critical for the approval of the VLT concept and budget. I was obviously identified by my Council colleagues as a stubborn advocate of the VLT interferometric mode. I must say that this required a great deal of trust on their part, because at the time we had very few very demonstrative results: we had to trust physics and engineering! But I should also add that our allies in the astronomical community, few but strong, and especially the team of engineers within ESO who were pursuing the detailed studies, played a big role so that after the approval of the VLT in 1987 and the choice of the Paranal site in 1989, interferometry could develop.

    2
    ESO Astronomical Observatory at Cerro Paranal

    During these years, I had not abandoned my scientific activity, which was focused on the experimental demonstration of adaptive optics, an absolutely essential step if we wanted interferometry to work with the 8-metre VLT Unit Telescopes. The remarkable support of ESO, the partnership with French Aerospace Lab, ONERA, a dedicated team and the understanding of the French authorities to use certain capacities developed for military purposes led to the first worldwide astronomical demonstration of adaptive optics in October 1989 at the Haute-Provence Observatory. A close double star was resolved, the seeing was defeated. Extraordinary prospects for high angular resolution with the new giant telescopes loomed on the horizon, while a generation of young doctoral and postdoctoral students joined us to prepare for the decade that was to follow.

    Q. You were involved in the VLT when it was still just a dream. How does it feel to now see it helping astronomers make incredible discoveries, including finding many exoplanets?

    A. At the end of the 1990s, when the NACO adaptive optics system was built for the VLT, I was not really surprised by the avalanche of observations and results that followed.

    ESO/NACO on Unit Telescope 1 (UT1)

    The first exoplanets had just been discovered and it seemed likely that NACO would be the first to directly image an exoplanet, which it did in 2003.

    However, the technical wager made on the VLTI interferometric mode was of a completely different nature. It almost collapsed in 1993 and it took several years of joint effort to get it back on track. It is quite extraordinary that as early as 2001, two of the four 8-metre VLT Unit Telescopes could be successfully coupled and that the coupling of the whole four-telescope system was successful in 2011. By then I had retired and reduced my scientific activity. However, in 2005, joining Reinhard Genzel’s vision, I contributed with some colleagues to drawing up a plan for a seemingly utopian new VLT instrument, GRAVITY, which has made incredible observations of the black hole at the centre of the Milky Way, SgrA*.

    ESO GRAVITY in the VLTI

    Needless to say, I am delighted to see that the VLTI, which is certainly unique in the world, is now capable of differential astrometric precision of the order of a few micro-arcseconds and has reached such a level of sensitivity that it is open to the ultrafine study of the orbits of exoplanets. I see in these successes the confirmation of my firm beliefs: confidence in young people, teamwork, and the strength of European cooperation, especially between research institutions and industry. The requirements of astronomers can push industry to its limit capabilities, or a bit beyond. Then, the immensity of the Universe becomes an endless source of discoveries.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Visit ESO in Social Media-

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    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

    Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT, a major asset of the Adaptive Optics system


    ESO LaSilla
    ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT 4 lasers on Yepun


    ESO Vista Telescope
    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO NTT
    ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT Survey telescope
    VLT Survey Telescope at Cerro Paranal with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


    ESO APEXESO/MPIfR APEX high on the Chajnantor plateau in Chile’s Atacama region, at an altitude of over 4,800 m (15,700 ft)at the Llano de Chajnantor Observatory in the Atacama desert.

    A novel gamma ray telescope under construction on Mount Hopkins, Arizona. a large project known as the Cherenkov Telescope Array, composed of hundreds of similar telescopes to be situated in the Canary Islands and Chile. The telescope on Mount Hopkins will be fitted with a prototype high-speed camera, assembled at the University of Wisconsin–Madison, and capable of taking pictures at a billion frames per second. Credit: Vladimir Vassiliev

     
  • richardmitnick 12:42 pm on June 12, 2020 Permalink | Reply
    Tags: "Twinkle twinkle little star but not on our watch", ESO’s Adaptive Optics Facility (AOF) beams out four laser guide stars to create an artificial laser guide star 80 km up in the atmosphere., ESOblog, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT a major asset of the Adaptive Optics system, Johann Kolb is an expert in adaptive optics.   

    From ESOblog: “Twinkle, twinkle little star, but not on our watch” 

    ESO 50 Large

    From ESOblog

    12 June 2020
    HighTech ESO

    1
    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo

    2
    Johann Kolb

    Johann Kolb is an expert in adaptive optics — the correction of the distortion of light caused by turbulence in Earth’s atmosphere. Involving advanced technologies like deformable mirrors and powerful lasers, adaptive optics can make images obtained by ESO’s telescopes almost as sharp as those taken in space. After spending 14 years at ESO Headquarters developing and testing new adaptive optics systems, Johann Kolb has spent the last four years at ESO’s Paranal Observatory in Chile installing adaptive optics systems on the telescopes and making sure that these systems perform well for twenty years or more.

    3
    Neptune imaged by the Very Large Telescope (VLT) with and without adaptive optics.
    Credit: ESO/P. Weilbacher (AIP)

    Q. First of all, could you tell us a bit about your role at ESO and what your day to day work looks like?

    A. My role is fundamentally to keep an overview of the adaptive optics systems at ESO’s observatories. Turbulence in Earth’s atmosphere reduces the quality of astronomical images and we use adaptive optics on our telescopes to correct for this. The technology has been around for 30 years and we’re now starting to see it everywhere — for example, we currently use 15 adaptive optics systems at Paranal Observatory; there are some differences between them but they all have similar components.

    This Adaptive Optics Paranal System Engineer role was created seven years ago because of the increasing number of adaptive optics systems at ESO. It’s mostly about knowledge management — gathering information, considering what problems might arise in the future, and making sure that we learn from current problems. I would say that about half my job is fixing problems, and the other half is planning for the future.

    Q. You now work at Paranal Observatory but you spent 14 years developing adaptive optics systems at ESO Headquarters in Germany. How does your current work compare to the work you did at ESO HQ?

    A. Indeed, I used to design, align and test adaptive optics systems that were then shipped off to Paranal. Now on the other side I’m involved once each system arrives at the telescope. The first step is to install it in the telescope and make sure it works. The team from HQ sets it up and reproduces the behaviour that it had when being tested in Europe, whilst the Paranal team watches and learns how to make it work best on the sky here in Chile. At these times, I work partly during the night to see how the instrument is working and partly during the day doing data analysis.

    In HQ I worked on three or four different adaptive optics systems so I think that experience was essential to allow me to do my job in Paranal well. Although lots of adaptive optics instruments have arrived since I came to Paranal four years ago, there were of course many that arrived before I did. I have spent time learning about how these work, including the commonalities and tools that allow us to analyse them in the same way.

    Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT, a major asset of the Adaptive Optics system


    ESOcast 119: AOF First Light
    ESO’s Adaptive Optics Facility (AOF) beams out four laser guide stars to create an artificial laser guide star 80 km up in the atmosphere.
    Credit: ESO

    Q. So how exactly does adaptive optics work and why is it so important?

    A. The key components are a reference star or a laser that excites sodium atoms around 80 kilometres above Earth’s surface, a wavefront sensor that observes how much the light from the sodium atoms or reference star is being distorted by the motion of air in Earth’s atmosphere, a deformable mirror that changes its shape to correct for the effects of the atmosphere, and a real-time computer that gets information from the wavefront sensor and sends information to the deformable mirror. The ultimate result of adaptive optics is that we better concentrate the photons from whatever scientific target we are observing, so that we can do better science in less observing time.

    4
    This image shows the construction of the deformable secondary mirror (DSM), one of the key systems of the VLT Adaptive Optics Facility (AOF) in Paranal, Chile. The thin shell being dismounted and the magnets glued to the back face are visible. To learn more about the mirror’s construction and testing read issue 151 of the Messenger. Credit: ESO

    One of ESO’s most complex adaptive optics systems is the Adaptive Optics Facility (AOF) on the fourth Unit Telescope of the Very Large Telescope (VLT). This is the famous one that people love to photograph, with the four laser guide stars shooting out. The deformable mirror is 112 centimetres in diameter but just two millimetres thick, and over 1100 little magnets change its shape 1000 times per second to correct for the constantly changing atmospheric turbulence.

    Q. You’ve been working at ESO for 18 years. What was adaptive optics technology like when you joined ESO and how have you seen it evolve during that time?

    A. The systems that were being installed 18 years ago are still there and we want to make them last ten more years. To be honest there are no major conceptual differences between those systems and the systems we are developing for the upcoming Extremely Large Telescope (ELT) — all the parts talk to each other in much the same way — but there have been some huge improvements in how the different parts work individually and everything has been scaled up a lot.

    For example, in the past we could only use reference stars to measure turbulence; knowing that these stars should be points of light, and knowing where their position should be, we can see how much the atmosphere distorts their light and correct for this distortion. The first generation of lasers arrived only around 2006, and they are particularly useful when there are no reference stars near the astronomical target that the telescope is pointing at (we want to find something as close as possible because atmospheric turbulence varies a lot across the sky). The second generation of lasers arrived in 2016, and these are the same as the ones we will use in the ELT.

    The computers have also of course become much more powerful in that time, meaning that the whole system can work quicker or handle more lasers and more motors to move the deformable mirror at the same time.

    One big improvement is that the latest systems use magnets — or magnetic actuators — to deform the mirror, rather than motors that physically puh and pull on the mirror. These magnets keep the thin mirror floating in the air — a bit like those desk globes that float due to a magnet above and below. And the same magnets can be used to pull the mirror in case of an earthquake, to ensure that the mirror doesn’t fall and get broken. Furthermore, twenty years ago deformable mirrors had around 60 of these actuators, whereas we now have 1170 on the AOF.

    Q. What will adaptive optics systems for the ELT look like?

    A. These will actually look very similar to the AOF. There will be 4–8 lasers, a wavefront sensor and the telescope’s fourth (of five!) mirror will be deformable. But relative to the size of the telescope, the systems will actually be smaller than the AOF. As I mentioned, we have over 1000 actuators for the 8-metre-wide VLT, but we will have over 5000 for the 39-metre wide ELT, which has a surface area more than 20 times that of the VLT. Some of the big challenges will be keeping the system stable and getting everything to work together.

    Q. Tell us about something interesting that you’ve been working on recently?

    A. To be honest (don’t tell my astronomer colleagues this!), for my professional needs, stars are just points of light; I don’t care what they’re doing, I just use them as a means to an end. But one of the latest adaptive optics systems is so powerful that it has been possible to analyse turbulence looking at not only reference stars but also the cores of galaxies, planets or moons, for example. This can be particularly useful when astronomers want to look at planets, moons, other galaxies or even quasars distorted by gravitational lenses, because there may be no nearby guide stars.

    Another important thing that the adaptive optics development team is working on with ESO’s detector team and European industry is reducing the noise in our detectors. Noise is an unwanted signal — it’s what makes photographs look grainy or blotchy, and we can have the same problem in our adaptive optics systems. So if we reduce the noise we can use fainter and fainter objects to analyse atmospheric turbulence, and we will soon have systems with ten times less noise than their predecessors.

    Q. What would you say is your biggest achievement personally whilst at ESO?

    A. One of my favourite projects was working on the Multi-Conjugate Adaptive Optics Demonstrator (MAD) where I was part of a great team working on a very sophisticated prototype that was the first to use several guide stars and several deformable mirrors at the same time. This project actually led to my first ever visit to Paranal when we installed MAD on the VLT in 2007; we spent a couple of months there working on the instrument and it was a fantastic experience.

    I then worked on the AOF for ten years, and I feel very proud that now, when an operator goes to use AOF they just press a button and everything — all the adaptive optics and science collection — happens automatically. In the previous generation of adaptive optics instruments, getting an instrument up and running could be twenty minutes of painstaking work!

    5
    A detailed view of the the Multi-Conjugate Adaptive Optics Demonstrator (MAD). It is a prototype MCAO system which aims to demonstrate in the laboratory and on sky the feasibility of different MCAO reconstruction techniques in the framework of the ELT concept and the 2nd Generation VLT Instruments. This photograph was obtained in May 2005. Credit: ESO

    Q. What route did you take to become an adaptive optics engineer?

    A. I always knew I would work in science, I just didn’t know which field. I’ve always been an amateur astronomer and at some point I converged to particle physics or astrophysics. I started learning a lot about scientific research which led me in the direction of instrumentation and so I studied for a master’s degree specifically in astronomical instrumentation. I was lucky enough to get offered an internship at ESO where I discovered a fascination for adaptive optics. And here I still am today!

    Q. ESO’s observatories have now stopped carrying out observations due to the coronavirus pandemic. Does this pause give you the opportunity to step back and evaluate what you’re doing and what you want to do next?

    A. At the moment I am focusing on completing tasks that don’t require being at the observatory, like developing algorithms, reviewing documents, documenting procedures and making plans for the future. As part of this, some questions are arising that I need to use the telescopes to answer, so I will make the most of them when the observatory re-opens again! At that time I will also focus more on the day-to-day challenges that come up.

    We had planned to install a couple of new instruments on the VLT over the next months, for example CRIRES+ and NIRPS. When we get back to the observatory we will be busy preparing for and installing them as soon as we can.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Bloc Icon

    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

    Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT, a major asset of the Adaptive Optics system


    ESO LaSilla
    ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT 4 lasers on Yepun


    ESO Vista Telescope
    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO NTT
    ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT Survey telescope
    VLT Survey Telescope at Cerro Paranal with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


    ESO APEXESO/MPIfR APEX high on the Chajnantor plateau in Chile’s Atacama region, at an altitude of over 4,800 m (15,700 ft)at the Llano de Chajnantor Observatory in the Atacama desert.

    A novel gamma ray telescope under construction on Mount Hopkins, Arizona. a large project known as the Cherenkov Telescope Array, composed of hundreds of similar telescopes to be situated in the Canary Islands and Chile. The telescope on Mount Hopkins will be fitted with a prototype high-speed camera, assembled at the University of Wisconsin–Madison, and capable of taking pictures at a billion frames per second. Credit: Vladimir Vassiliev

     
  • richardmitnick 11:20 am on May 30, 2020 Permalink | Reply
    Tags: "Who’s who on the ELT: part I", , , , , ESOblog   

    From ESOblog: “Who’s who on the ELT: part I” 

    ESO 50 Large

    From ESOblog

    The faces behind the world’s biggest eye on the sky

    29 May 2020
    People@ESO

    1

    Bigger than all existing optical research telescopes combined, ESO’s Extremely Large Telescope (ELT) will drive astronomy into the future, tackling the biggest scientific challenges of our time. But to construct such an innovative and powerful telescope, it takes many different people working in an enormous variety of roles. In this series of blog posts, we hear from some of the people working on the ELT, exploring the work they do to help us reach the stars.

    Suzanne Ramsay (Instrumentation Manager)
    Claudio Cabrera (Civil Engineering Project Manager)
    Jason Spyromilio (Telescope Scientist)
    Miska Le Louarn (Adaptive Optics Physicist)
    Elizabeth George (Detector Engineer)
    Dominik Schneller (Systems Engineer)
    Ulrich Lampater (Control Engineer)
    Dimitris Kalaitzoglou (Retired Power Engineer)

    Suzanne Ramsay (Instrumentation Manager)

    2
    Suzanne Ramsay at the SPIE instrumentation conference in 2018, next to a 1:1 scale print out of the ELT’s METIS instrument without its support structure.
    Credit: ESO/Suzanne Ramsay

    “I am responsible for delivering the first instruments to the ELT. All of these are built outside ESO by large consortia of universities and institutes mostly in the ESO Member States. So maybe you can guess that much of my working day is spent in meetings of varying sizes, from internal discussions with a few ESO colleagues to consortium progress meetings with 100 people.

    My work in astronomical instrumentation started with my PhD at the University of Edinburgh in the UK. A chance remark by one of my undergraduate professors made me think about doing something that combined practical work with astronomical research and I have always been grateful for this comment; there is something satisfyingly tangible about an instrument project — a different satisfaction from producing a research paper. Every astronomical instrument is a one-off; the ELT’s instruments are incredibly challenging thanks to the colossal size of the telescope.

    I have worked on many instruments and every one’s “first light” — the first time you get a star on the detector — is burned into my memory. This moment is the culmination of years of work by the instrument team and is a real cause for celebration. The on-sky commissioning periods that follow are very intense — not always easy but there is a great focus by the team on what needs to be done. In the ideal cases, everyone is working and working together at their best. Many colleagues will probably laugh at this — it’s also a good time for stress and lack of sleep to cause arguments!

    Aside from the instruments, I am fascinated by the breadth of topics that have to be considered for this telescope — from the geological details of the new mountain top to the incredible precision with which the 798 mirror segments have to be controlled to deliver the quality of images that astronomers expect. The most memorable moment on the ELT project for me was the first (and so far only) trip to the new telescope site on Cerro Armazones. Simply breathtaking.”

    Claudio Cabrera (Civil Engineering Project Manager)

    3

    Claudio Cabrera building a small plane, one of his hobbies.
    Credit: ESO/Claudio Cabrera

    “I grew up in a small city named Ovalle, which is close to a city where the first observatories were built in Chile back in the ‘60s. I have always felt some fascination for those places sitting at the summit of a big mountain. So, when I saw ESO was looking for a Civil Engineer back in 2008, I didn’t think twice and I was lucky enough to be selected to lead the ESO ALMA site team. One of the nice moments I’ll always remember at ALMA was the telescope’s inauguration and the good times we had during the construction period when I was head of the site development group.

    My role within the ELT is Civil and Infrastructure Project Manager and is all related to roads, earth works, some logistics aspects, buildings, and more. In construction, there is no fixed schedule; sometimes you start the day with something in mind and, after some hours, you end up doing something completely different — that variety of each day is what I enjoy most about my job.

    One particularly interesting moment was the first blasting made at the Armazones top platform in June 2014. It was the start of the removal of three-quarters of a million tonnes of rock. When I’m not working, I like to be at home with my wife and three adult daughters; I live close to a mountain and go on walks there with my family and friends. And recently, I restarted a hobby I had when I was a kid: building little aeroplanes that fly using electric or combustion engines.”

    Jason Spyromilio (Telescope Scientist)

    4
    Jason Sypromilio presenting.
    Credit: ESO/Jason Spyromilio

    “As the Telescope Scientist my job is to commission the ELT and deliver a working telescope to its users. To prepare for this, I work with some very talented people in ESO to develop the baseline operation and calibration strategy for the telescope while keeping an eye on the evolution of the hardware and software systems as they are being implemented. A typical day involves reading and writing documentation, coding simulations, and having many discussions with colleagues about solutions to real and imaginary problems. I have had the privilege of being involved with the ELT project in various roles from its inception and I enjoy learning about, and understanding, the physics of telescopes.

    I was fortunate, soon after I joined ESO in 1994, to be given the opportunity to head up the New Technology Telescope upgrade project and after that to lead the commissioning effort at the Very Large Telescope (VLT). One of the challenges of enormous telescopes is that you don’t get to test them in the lab before going to the mountain so I guess much will be revealed when we go to Armazones and I look forward to finding out what I got right and what not. Certainly the scientific highlight of my career has been my participation in the discovery of the accelerating expansion of the Universe together with Bruno Leibundgut here at ESO and many colleagues around the world. On the technical side, I have great recollections of the first stars of each of the telescopes and later seeing the happiness of instrument teams after they successfully attach to the telescope.

    When I’m not working, I run and ride my bike and, when I can, I go to where the waters are warm, the winds favourable and, depending on the company one keeps, the dolphins plentiful. I was born in Athens and love the Aegean, but unfortunately Munich is far from it and Chile even farther.”

    Miska Le Louarn (Adaptive Optics Physicist)

    5
    Miska Le Louarn.
    Credit: ESO/Miska Le Louarn

    “I have been doing astronomy since I was a kid. During an internship at NASA, I used one of the first adaptive optics systems with a laser guide star system to observe a comet crash on Jupiter. This event steered me towards adaptive optics — using mirrors to correct for how turbulence in Earth’s atmosphere distorts light from the Universe. Years later, seeing the four laser guide stars of the Adaptive Optics Facility working together on the VLT was the conclusion of many years of studies and simulations that I had started doing during my PhD thesis. This was the proof that almost 20 years of work was not done in vain. Now my work consists of doing adaptive optics simulations for the ELT and its instrumentation. I simulate how light propagates through Earth’s turbulent atmosphere, the telescope and its deformable mirror and finally reaches the scientific instruments. This allows me to model how images taken by the ELT will look, depending on the characteristics of the adaptive optics system that we use.

    One of my favourite things about working on the ELT is being in an international environment, with people from many nationalities coming together to work on common projects. I also like the mixture of high-tech and scientific research that I am able to work on. Since a telescope this large has never been built before, we have to explore many different aspects and that is what makes it so interesting. When I’m not sitting in front of a computer working on simulations, I love to cycle and run. I’ve even done a few ultra-marathons!”

    Elizabeth George (Detector Engineer)

    6
    Elizabeth George leading an ESO social day trip to Alspitz.
    Credit: ESO/Elizabeth George

    “I’ve always been one of those people who asks “why” when presented with a new piece of information. This made me an especially annoying child, but an excellent scientist. I started studying physics because I wanted to understand how the Universe works. But it turns out we don’t understand everything yet, so I got into engineering instruments for astronomy because I wanted to build the equipment we need to find out more about the Universe. My main role in the ELT is that I am the lead engineer and project manager for scientific detector systems for HARMONI, the first-light spectrograph for the ELT. No two days are the same for me! One day, I may spend a lot of time interacting with scientists and engineers from all over Europe to make sure that when we go to put the detectors into HARMONI they work the way they should. On another day you might find me in the lab integrating a detector into a cryostat to keep it at a very low temperature. A few days later, you would find me at a computer operating the detector system and analysing the data we get back.

    The most memorable moments in my career so far have always been “first light” moments: The first time a detector is working in the lab, the first time a detector is working inside of its instrument, and, the best, first light on the telescope when you see the first bit of light from a star or galaxy. I am willing to try my hand at almost anything, both at work and outside of it. I’ve participated in so many different sports from the more obscure like pole vaulting, kayak polo and caving, to the mainstream like biking and running. I have also tried to fix nearly everything around the house from sewing clothes to welding pipes. I figure you can learn something new from every experience in life, so why not try lots of new things?”

    Dominik Schneller (Systems Engineer)

    7
    Dominik Schneller at Cerro Armazones in front of the ELT construction grounds.
    Credit: ESO/Dominik Schneller

    “Early on, I had a strong curiosity for understanding how things work. This started with playing with LEGO and developed into disassembling old household equipment, such as phones and radios. My curiosity ultimately led to an interest in the field of computer technology including my first experience in coding. Today, I am a member of the ELT Systems Engineering group and some of the things I am responsible for include writing technical requirement specifications for the procurement of ELT subsystems and overseeing changes to, and interfaces between, the contracts we have with external partners to develop parts of the ELT. The daily work is technically challenging but extremely interesting, and it is a real pleasure because we have a lot of great colleagues on our team.

    The ELT is a machine at the edge of technology, providing lots of interesting work and insights to the latest high tech in many fields. It is a once-in-a-lifetime opportunity for people who are interested in astronomy and will contribute significantly to the advancement of humankind. Outside of work, I have several outdoor hobbies like sailing, swimming, paragliding, motorbiking. More recently, my passion for flight simulators has been reactivated. I also like to travel, but in rather unusual ways. I have already done various long distance motorcycle trips including to Istanbul and St. Petersburg, but my most interesting trips were to North Korea and Iran. The visit to Paranal Observatory and the Very Large Telescope was also a mind-blowing experience; its uniqueness and beauty is just breathtaking!”

    Ulrich Lampater (Control Engineer)

    8
    Ulrich Lampater characterising a cryocooler that cools parts of a telescope and its instruments to extremely low temperatures.
    Credit: ESO/Babak Sedghi

    “I have always been fascinated by aeroplanes and space exploration, so I studied aerospace engineering and got especially hooked on control engineering. To me, it is a bit like magic powder that makes all the individual parts of a system work together. You push a button and it moves! At the end of my studies, I got the offer to work on a telescope called SOFIA that is installed on an aeroplane. This is how I got into astronomy, and now I find telescopes even cooler than aeroplanes. As a Control Engineer for the ELT, I help make sure that active devices of the telescope are designed and implemented such that they fulfil their — usually quite challenging — performance requirements. Control engineering requires close interaction with various disciplines, so our work depends on input from many experts. Fortunately ESO has highly skilled and very motivated staff, making it easy to find experts for in-depth discussions, who will challenge my conclusions.

    To me, a good day at work is one where I learn something new or get a new perspective. One of the most memorable moments of my career was being part of the team that acquired the first guide star on the SOFIA telescope while being airborne, and then the first airborne light on a science detector only a few nights later. This is the moment when all the hard work of so many people paid off. For the ELT this moment is of course still far away. But in the end it is probably not about the moment itself, but the common journey of all those involved that leads up to it. I am happy to contribute my small part to this journey.

    Dimitris Kalaitzoglou (Retired Power Engineer)

    8
    Dimitris Kalaitzoglou in front of a transformer.
    Credit: ESO/Dimitris Kalaitzoglou

    “Before retiring, my role was to help the ELT Programme Manager realise the Chilean President’s commitments to provide electricity to the ELT from the Chilean grid, and cooperating with both partners was what I enjoyed most about my work for the ELT. One of the most memorable moments of my career was the December 2013 visit of SAESA (a Chilean electricity company) Directors to Paranal Observatory, when it was initially confirmed that SAESA would work in cooperation with ESO for an ELT grid connection. The inauguration of Cerro Armazones in July 2017 was also an amazing moment and reminded me of my past experiences in Greece visiting high voltage substations. Now that I am retiring, I am happy to return permanently to the sun in Greece.”

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Visit ESO in Social Media-

    Facebook

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    ESO Bloc Icon

    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

    Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT, a major asset of the Adaptive Optics system


    ESO LaSilla
    ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT 4 lasers on Yepun


    ESO Vista Telescope
    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO NTT
    ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT Survey telescope
    VLT Survey Telescope at Cerro Paranal with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


    ESO APEXESO/MPIfR APEX high on the Chajnantor plateau in Chile’s Atacama region, at an altitude of over 4,800 m (15,700 ft)at the Llano de Chajnantor Observatory in the Atacama desert.

    A novel gamma ray telescope under construction on Mount Hopkins, Arizona. a large project known as the Cherenkov Telescope Array, composed of hundreds of similar telescopes to be situated in the Canary Islands and Chile. The telescope on Mount Hopkins will be fitted with a prototype high-speed camera, assembled at the University of Wisconsin–Madison, and capable of taking pictures at a billion frames per second. Credit: Vladimir Vassiliev

     
  • richardmitnick 1:28 pm on May 15, 2020 Permalink | Reply
    Tags: , , , Carole Haswell, , , ESOblog,   

    From ESOblog: “Hunting hot exoplanets” 

    ESO 50 Large

    From ESOblog

    15 May 2020
    Science Snapshots

    1
    Carole Haswell

    In December 2019, astronomers announced that they had efficiently discovered and characterised planets outside the Solar System using an innovative technique. So far, the researchers have used the technique with ESO’s HARPS instrument to find six exoplanets, some of which hold the key to unlocking the geology of rocky planets. We spoke to lead researcher Carole Haswell from the Open University in the UK to find out more about the project and the implications of these discoveries.

    ESO 3.6m telescope & HARPS at Cerro LaSilla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    2
    Artist’s impression of the mass-losing giant planet DMPP-2b, which orbits the pulsating star DMPP-2 every five days. The star is viewed through a cloud of gas lost from the hot planet.
    Credit: Mark A. Garlick / markgarlick.com. Science credit: Haswell / Barnes / Staab

    Q. The Dispersed Matter Planet Project (DMPP) aims to find lots of new exoplanets. What motivated you to start this project?

    A. The project actually grew out of some research we did a decade ago using the Hubble Space Telescope. We were looking at giant exoplanets, and found that the chromosphere of one of the host stars was missing. It seemed extremely unlikely that this star would be structured differently to every other star we know of, so we had another idea: when planets orbit close to their host star, they are heated very vigorously which makes them lose mass. We figured that some of this mass could form a gas shroud that envelops the entire planetary system and absorbs the light from the star’s chromosphere, preventing us from seeing it.

    So, we had the idea that if we see a star with missing chromospheric emission, we know that there is a hot mass-losing planet present, and could actually deduce a lot of information about such a planet. In this way, we came up with a new and efficient technique to discover new low-mass planets orbiting close to their parent star.

    What makes the project really special is our target star selection. Astronomers are beginning to suspect that most stars have planets orbiting them, but when we know what kind of planet a star might host, we can tailor the observations to find out about the planet much more quickly. And this is exactly what we’ve been doing here.

    Q. Could you tell us a bit about how this new planet-searching technique works?

    A. We searched through existing data on 6000 stars to find any that were structured like the Sun but with missing emission from their chromospheres. Of these 6000, we found about 40 that we thought could host very hot mass-losing planets. As these were all nearby stars, we guessed that these planets would have been found already if they were large and massive, so we thought they must be small, light planets. Therefore we designed observations to find them using the very sensitive HARPS instrument on the ESO 3.6-metre telescope [below and above].

    Because we were expecting low-mass planets orbiting close to their host stars — and therefore orbiting very quickly — we needed to get frequent measurements of the same star to see the differences during the planet’s orbit. So we looked at each star several times a night, which is much more often than observations are usually designed.

    Visiting La Silla Observatory to use the ESO 3.6-metre telescope was one of the most amazing experiences of my life. I’d used the New Technology Telescope [below] some years ago, but because I believe that this research is the best idea I’ve had in my whole career, it was especially exciting to go this time round.

    Q. What makes HARPS so good at finding new planetary systems?

    A. For this project, we are using the radial velocity method to detect planets, which means we measure how quickly the star moves towards and away from us. When a planet orbits a star, it pulls the star towards itself slightly. This means that when the planet orbits the star, the star is also executing a much smaller orbit in response. The star moves towards us while the planet moves away from us and vice versa. We can detect these changes in the star’s velocity from Earth.


    The radial velocity method for finding exoplanets. Credit: ESO/L. Calçada.

    We chose to use HARPS because it is by far the best general user radial velocity instrument that we were allowed to propose for — it can measure the velocity of a star with a precision of less than one metre per second! It’s fantastic to be in an ESO Member State with the opportunity to use such an instrument.

    Q. So why do you think it is important for us to search for new exoplanets?

    A. One of the biggest human questions is about our place in the Universe; how special the Solar System is and how special Earth is. And one of the big pushes in exoplanet science is to extend discovery methods to be able to see planets like Earth orbiting their host stars at the same distance that Earth orbits the Sun. The idea is that these Earth-like planets could be good candidates for hosting life.

    But it’s also important to find a whole range of planetary systems to see how planets form and evolve and to determine how typical the Solar System is. The planets we are studying through this project aren’t similar to our neighbours in the Solar System, but it is nonetheless important to study them because it gives us the opportunity to better understand a different type of planet, which is important to generally understand the geology and geochemistry of planetary systems.

    With further study of the systems we’ve found to host exoplanets, we could work out the chemical composition of the gas shroud, which would reveal what type of rock the surfaces of these planets are made of. This will help us pin down how planets are built, and whether the Earth is normal.

    Q. How has the DMPP been going so far? Have you had any surprising discoveries?

    A. We started making observations in 2015, and we’ve already discovered six exoplanets using relatively little telescope time compared to more traditional methods. One of the most interesting stars we looked at so far actually turned out to be two stars! The tiny second star in the binary system is right at the lower limit of hydrogen burning, meaning it is just massive enough to be a proper star like the Sun. If it had slightly less material, it would be a brown dwarf. This star is faint and had therefore never been detected before. Finding this extremely low mass star was interesting in its own right, but we also found a planet in this system that is 2–3 times the mass of Earth and orbits the larger star in just seven days, which is unusually quick. The planet doesn’t fit with our theories of planet formation because the smaller star’s presence means there wouldn’t have been enough rocky material to form the planet where we see it. The second star must have affected the planet’s orbit, somehow pushing it closer to the larger star.

    We would really like to study this system in more detail; if we can get more radial velocity data, we could see if there are any other planets, pin down the properties of the planet we’ve already discovered, and look at the atmosphere of the smaller star to see how it changes as it gets close to the larger star.

    Q. Are there any challenges that you’ve had to overcome?

    A. For many of our target stars we have detected more than one orbiting planet, so it took us a while to disentangle the signals from each other to figure out the exact number of planets and their orbital periods. This meant it was longer than expected before we could publish our results, so the committee that allocates telescope time started becoming sceptical and we had to persuade them that our research really is worthwhile. We’ve now published several papers on our discoveries, and we were allocated more time to continue the project — both to look at more systems and to investigate the most interesting ones in more detail. Unfortunately these observations couldn’t take place because of the closure of the observatory due to COVID-19, but we are really keen to continue as soon as it is safe to do so!

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Bloc Icon

    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

    Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT, a major asset of the Adaptive Optics system


    ESO LaSilla
    ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT 4 lasers on Yepun


    ESO Vista Telescope
    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO NTT
    ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT Survey telescope
    VLT Survey Telescope at Cerro Paranal with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


    ESO APEXESO/MPIfR APEX high on the Chajnantor plateau in Chile’s Atacama region, at an altitude of over 4,800 m (15,700 ft)at the Llano de Chajnantor Observatory in the Atacama desert.

    A novel gamma ray telescope under construction on Mount Hopkins, Arizona. a large project known as the Cherenkov Telescope Array, composed of hundreds of similar telescopes to be situated in the Canary Islands and Chile. The telescope on Mount Hopkins will be fitted with a prototype high-speed camera, assembled at the University of Wisconsin–Madison, and capable of taking pictures at a billion frames per second. Credit: Vladimir Vassiliev

     
  • richardmitnick 10:45 am on April 13, 2020 Permalink | Reply
    Tags: "A spotlight on Claudia Cid", , , , , ESOblog   

    From ESOblog: “A spotlight on Claudia Cid” 

    ESO 50 Large

    From ESOblog

    10 April 2020
    People@ESO

    1
    Interview with Claudia Cid

    A telescope operator on fixing banana stars, searching for lasers and enjoying Paranal sunrises.

    2

    ESO’s telescopes collect lots of incredible information about the Universe, but who tells them where to point and what data to collect? Claudia Cid is a Telescope Instrument Operator and Operations Specialist at ESO’s Paranal Observatory. Her job is to make sure the telescopes and instruments collect the best data that they can to help astronomers find out more about the Universe.

    Q. What does your day to day work look like?

    A. Well, it’s night to night work actually! On any given night, I operate one of the telescopes at Paranal Observatory to make sure that we get the best possible scientific data given the meteorological conditions at that time, whilst ensuring that people and telescopes remain safe. Recently, for example, I’ve been working with the Very Large Telescope (VLT) UT4, Yepun, which means I’ve been handling the lasers!

    What my role actually involves is typically working with an astronomer for the first half of the night and alone for the second half of the night. Everything is computerised, so we sit down in front of lots of screens in the control room and start up the telescope remotely. We have a bank of observing programmes submitted by astronomers around the world, and we use a tool to select which programme we should observe depending on the current conditions — we account for wind, turbulence in the air, cloud cover, humidity, etc. When astronomers submit a programme they provide information about what conditions their observations require.

    3
    Operators and astronomers at work in the VLT control room. Credit: ESO/L. Honnorat

    Once a programme has been selected, the telescope moves to point at the right coordinates on the sky. When a telescope has pointed to a new object, the object tends to look out of focus like a banana or a donut, so I adjust the telescope’s mirror until the object is in focus. Then the telescope starts tracking the sky and I constantly monitor all the systems; this includes the enclosure, the hydraulics, the electronics and the light that’s coming in.

    4
    Data coming in from the HELIOS instrument on the ESO 3.6-metre telescope.Credit: ESO/X. Dumusque

    At this point, if the astronomer is present they take care of operating the instrument that detects the light collected by the telescope. We keep an eye on the data to check its quality; if it’s not good enough, the observations have to be repeated with better conditions. I work on different programmes like this, moving from one target to another, until the Sun begins to rise, at which point I put the telescope in a parking position, with the mirror looking up, close the dome and make sure everything is left in a safe state.

    Q You were on the team in charge of collecting the last photons from the VLT before science operations were paused for the first time in Paranal’s history. How did this feel?

    A. Being on the mountain for the last shift before the observatory was closed down due to the coronavirus outbreak was scary and exciting. Before leaving home, we didn’t know what would happen and then on the mountain we were witnessing the number of people reducing everyday. But being responsible for operating UT4 during that last shift was a real life challenge — operating under reduced conditions and having no backup on the mountain in case things went wrong made for a very satisfying shift. The control room was so empty but the group pulled it off; I have to thank my remote astronomer for his help, as well as the rest of the “last photons” team.

    Q. What do you enjoy most about your job when the telescopes are operating as normal?

    A. The mornings! After I close up the telescope system, the Sun is starting to come up over the horizon, the air is cold, the mountains look beautiful, I feel satisfaction about having got my job done, and I know it’s time to go to bed.

    I also like that every night is different. Although we use the same telescopes and instruments, we could be looking at comets, star clusters, distant galaxies, or something else entirely.

    Q. Do you find night shifts tough?

    A. I did exclusively night shifts for 15 years! I’m definitely not a morning person. As an operator I always work one week of long shifts — sleeping at the Residencia during the on-shift week — then one week off the mountain at home, and I don’t get up early when I’m off to maintain the shifted schedule. I don’t feel ashamed about this at all!

    Q. You’ve worked at ESO for 17 years; how have you seen operations at Paranal change during that time?

    A. I’ve seen many changes, many instruments have been commissioned, and many have been decommissioned. My work is of course “easier” now than it was 17 years ago because we have many more tools to help us operate the telescopes and instruments. These allow us to better understand what we’re observing, the problems we’re facing, and whether the science we’re collecting is good or bad. I didn’t study astronomy, so that was actually something tricky for me when I first joined ESO.

    I’ve always worked in the control room, but in the beginning operators were just telescope operators. Now we have tools to better understand the science as it comes in, so we also operate instruments without an astronomer present.

    Q. And having worked at ESO for so long, what inspires you to continue going to work every day?

    A. To put it simply, I like the job! I always go to work happy because I find it fun and I feel like I can make a difference. This year I’m spending a lot of time training new operators, as well as training astronomers to do operations. It feels great when they trust my knowledge and experience. Besides, I think you have to be kind of special to do this job. It involves working alone a lot, so you have to be comfortable with your own company.

    Q. What are the biggest challenges that you’ve faced, and how have you overcome them?

    A. Oh, we often face minor technical problems but rarely anything out of the ordinary. For example, UT4 (Yepun) uses Laser Guide Stars. These help us reduce the turbulent effect of Earth’s atmosphere on the light we receive. It takes a lot of experience to perform observations with the aid of lasers, so it takes longer than usual to propagate their light, ensure they are correctly aligned and centred in our laser cameras and then operate them when observing a science target. But some things happen automatically, for example if an aircraft is detected nearby the lasers turn off immediately for safety reasons. A dedicated tool also allows us to see where other telescopes are pointing to make sure the lasers don’t interfere with our observations.

    Challenges are always overcome by just paying attention and not getting distracted so that we don’t make mistakes. If mistakes are carried into the science, this could lead to poor quality scientific data, meaning we’d have to retake the data and therefore lose precious and expensive telescope time.

    The number one rule is to always know where the telescope is pointing. If I get up to grab a coffee or stretch my legs, I always check what the telescope is doing and how much remaining time there is on the current target. You always have to be aware of what’s going on.

    4
    VLT Control Room. On the left is Claudia Cid (TIO; Telescope Instrument Operator), and on the right is Celia Cerón (DHA; Data Handling Administrator). Credit: ESO/Max Alexander

    Q. How did you get to where you are today? What inspired you to become an operator?

    A. We joke about the Telescope Instrument Operators wanting to be operators, because (although I love the job) nobody really grows up dreaming of being an operator! I actually stumbled across an advertisement for the job in a newspaper around the time I was graduating from university. I felt like they were talking to me with the list of experience and skills that the job required. I have a degree in engineering and feel that my personality is very well-suited to this job.

    So I applied but I actually didn’t make it! I was the second choice candidate and I was told that a new operator position might open in the next few months, and if so, I’d get a call. Well, no call came so I became an electronics teacher. A year later, the call came! Now that I am training others to operate telescopes I feel like I am combining my two loves — operations and teaching others.

    Q. And finally, what do you do when you’re not operating telescopes?

    A. I let myself be pampered! I’m a family person, so during my weeks at home, I often visit my sister and generally enjoy spending relaxed time with my family without worrying that I’ll be back at work the next day. I’m also currently working on digitalising some old films from my childhood, which is a really cool project.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Bloc Icon

    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

    Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT, a major asset of the Adaptive Optics system


    ESO LaSilla
    ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT 4 lasers on Yepun


    ESO Vista Telescope
    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO NTT
    ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT Survey telescope
    VLT Survey Telescope at Cerro Paranal with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


    ESO APEXESO/MPIfR APEX high on the Chajnantor plateau in Chile’s Atacama region, at an altitude of over 4,800 m (15,700 ft)at the Llano de Chajnantor Observatory in the Atacama desert.

    A novel gamma ray telescope under construction on Mount Hopkins, Arizona. a large project known as the Cherenkov Telescope Array, composed of hundreds of similar telescopes to be situated in the Canary Islands and Chile. The telescope on Mount Hopkins will be fitted with a prototype high-speed camera, assembled at the University of Wisconsin–Madison, and capable of taking pictures at a billion frames per second. Credit: Vladimir Vassiliev

     
  • richardmitnick 11:51 am on March 28, 2020 Permalink | Reply
    Tags: , , , , , ESOblog, María Díaz Trigo, X-ray binary systems, XRISM is a JAXA/NASA collaborative mission with participation from the European Space Agency (ESA).   

    From ESOblog: “From the ground to the sky” 

    ESO 50 Large

    From ESOblog

    1
    27 March 2020. People@ESO.

    As well as being an Operations Astronomer at the ESO ALMA Regional Centre, María Díaz Trigo is a world-renowned expert in high-energy astrophysics and lends her expertise to X-ray space missions. In this week’s blog post, we find out what Maria does on a daily basis, how she fits everything in, and why she thinks it’s important that ground- and space-based astronomy evolve in parallel.

    2
    María Díaz Trigo

    3
    Artist”s impression of the black holes studied by the astronomers, using ULTRACAM attached to ESO’s Very Large Telescope [below]. The systems — designated Swift J1753.5-0127 and GX 339-4 — each contain a black hole and a normal star separated by a few million kilometres. That’s less than 10 percent of the distance between Mercury and our Sun. Because the two objects are so close to each other, a stream of matter spills from the normal star toward the black hole and forms a disc of hot gas around it. As matter collides in this so-called accretion disc, it heats up to millions of degrees. Near the black hole, intense magnetic fields in the disc accelerate some of this hot gas into tight jets that flow in opposite directions away from the black hole. The orbital period of Swift J1753.5-0127 — just 3.2 hours — is the fastest found for a black hole. The orbital period of GX 339-4, by contrast, is about 1.7 days. Credit: ESO/L. Calçada.

    Q. Firstly, could you tell us a bit about your role at ESO? What do you do on a daily basis?

    A. I’m an ALMA astronomer, meaning half of my time is dedicated to ALMA Observatory duties.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    This spans a range of activities, including scheduling different projects to happen at the right time, under the right conditions.

    The other half of my time is spent on my own research, where I am really free to work on whatever I want. So I focus on X-ray binary systems, which consist of either a small black hole (by which I mean around ten times the mass of the Sun!) or a neutron star, as well as a normal star. The black hole or neutron star pulls matter from the normal star. This process, called accretion, powers the most energetic phenomena in the Universe and releases a lot of X-rays. These X-rays can be observed using dedicated space telescopes, and I look at these X-ray observations together with observations of the same systems in other wavelengths of light made by telescopes on the ground. This gives me a lot of information about what’s going on in different parts of the system.

    Q. What first got you interested in astronomy?

    A. At university I specialised in particle physics, but after my master’s degree, particle physics seemed to be at the stage where the most exciting science had already been done. It is also difficult to work on your own research in particle physics; everything needs big expensive particle accelerators and extensive collaborations. So I switched to astronomy because of the amazing number of things that can be done with telescopes — both by collecting new data and by analysing data that already exist.

    4
    This artist’s impression shows the surroundings of a supermassive black hole, typical of that found at the heart of many galaxies. The black hole itself is surrounded by a brilliant accretion disc of very hot, infalling material and, further out, a dusty torus. There are also often high-speed jets of material ejected at the black hole’s poles that can extend huge distances into space. Observations with ALMA have detected a very strong magnetic field close to the black hole at the base of the jets and this is probably involved in jet production and collimation. Credit: ESO/L. Calçada.

    Q. And you are now an expert in high-energy astrophysics. Could you tell us a bit more about your research and why it inspires you?

    A. When a black hole or neutron star in a binary system pulls matter from a companion star, a disc forms around the black hole or neutron star, consisting of matter dragged off of the companion star, and this is what feeds the heavier object. At some point this disc is heated so much that the upper layers evaporate and matter flies away from the system in the form of winds. These winds have speeds of the order of 1000 km/s and are detected predominantly in X-rays and sometimes with telescopes that observe optical light. However, these winds are “slow” compared to the very narrow, collimated, extremely high-speed jets that are also expelled from the system and detected from radio to infrared wavelengths.

    I study these winds and jets and try to figure out how they fit in with the rest of the system. One of the biggest mysteries is how to feed black holes so that they get as big as those found at the centres of galaxies, which weigh as much as millions of Suns. Even if black holes are attracting matter from gas and stars, it seems as if a significant part of that matter is ejected in winds and possibly jets before it even gets to the black hole, so we’re still wondering how matter actually reaches the black hole so it can grow.

    Q. How does this research fit in with being a European Participating Scientist for JAXA’s X-ray Imaging and Spectroscopy Mission (XRISM)? Why did you choose to take on this role?

    3
    Artist’s impression of the JAXA/NASA X-ray Imaging and Spectroscopy Mission (XRISM).
    Credit: JAXA

    A. Well, I wanted to contribute to making the mission a success in getting us to the next stage of X-ray instrumentation! XRISM is a JAXA/NASA collaborative mission, with participation from the European Space Agency (ESA). It will carry a revolutionary micro-calorimeter providing a spectral resolution higher than conventional X-ray imaging spectrometers by a factor of 30. A micro-calorimeter will also be flown on ESA’s next large X-ray space mission Athena and we hope to learn lots of lessons from XRISM!

    I was selected by ESA around two years ago to represent the European scientific community on XRISM, and I mostly contribute scientific expertise in the area of X-ray binaries. I meet with a whole group of participating scientists every six months in person and monthly remotely, and we form part of the mission’s science team. We are currently considering which X-ray-emitting objects we should observe during the first six months after XRISM is launched in 2022, which will be the performance verification phase. During this period we will use the telescope to observe lots of different sources to check how the instrument fares — where it works well and where it works less well — so that the science community can prepare their own observations for the operational phase.

    Q. Do you think it’s important that ground-based astronomy and space-based astronomy evolve in parallel, with astronomers from both areas working together? If so, why?

    A. Absolutely! Astronomy is a complex science and one telescope observing one wavelength of light is not enough to have a full picture of what’s going on out there in the Universe. For example, one mystery surrounding black holes is that the supermassive black holes at the centre of galaxies emit X-rays, and so do the little black holes that I observe in binary systems, but medium-sized black holes don’t emit any X-rays! We didn’t even know whether these medium-sized black holes existed until gravitational waves allowed us to detect them for the first time. Now we can find out more about them and figure out why we don’t see any X-rays from them.

    Q. And what about collaboration between different scientific organisations? Why is this important?

    A. Knowledge sharing is always important. ESO and ESA have an ongoing collaboration to share knowledge and experience in the areas of science, technology and operations. This is mostly done through a working group for each of the three areas. I am part of the science working group in which we try to see where we can collaborate to advance scientific projects. For example, for some ESA space missions to achieve their full science goals, their observations are followed up by ESO’s ground-based telescopes.

    ALMA itself is a partnership between ESO, the US National Science Foundation, and Japan’s National Institute of Natural Sciences in cooperation with the Republic of Chile. So representatives from most continents are involved and the telescope is showing what can be achieved through a global collaboration. It’s hard work but very, very rewarding.

    Space missions are also becoming more complex and expensive, making it difficult for one agency alone to build and fund them. Costs and expertise have to be shared; this is demonstrated in XRISM where expertise comes from scientists around the world.

    Q. It sounds like you’ve got a lot on your plate! How do you fit everything in?

    A. (María laughs) I do what I can! It is a lot, but it’s one of the challenges that comes with working in science. The 50% of time many scientists have available to spend on “‘science” is not really all “own research time” in the end. We have to do a lot of work for the community otherwise the community can’t move forward. Being involved in advisory committees or selecting proposals from other scientists for observations with a given telescope indeed leaves less time for research, but it means that we extend and share our expertise.

    For example, for XRISM I contribute my knowledge about X-ray binaries, but there are so many other objects out there that emit X-rays. I’ve recently been learning from cosmological experts who work on very, very distant X-ray-emitting clusters of galaxies.

    Q. Finally, you’ve also got a degree in philosophy. How does that fit in with your interests in physics and understanding the Universe?

    A. Aside from being influenced by a fantastic teacher, I was always very attracted by philosophy because it’s at the core of thinking. Centuries ago, philosophers were the physicists of their times – their aim was to understand the Universe. Nowadays unfortunately we’re locked into small areas of expertise making it difficult to see the bigger picture. I found this very unsatisfactory; I can do many things to better understand my little black holes but in the end our aim is to discover why we are here and where we go now. I can’t answer these questions with my data alone.

    Seeing the bigger picture gives us a direction, something to aim for. Fortunately, we are now moving in the direction of multidisciplinary work; people from different areas are working together and combining their knowledge to solve bigger problems.

    See the full article here .


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    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

    Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT, a major asset of the Adaptive Optics system


    ESO LaSilla
    ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT 4 lasers on Yepun


    ESO Vista Telescope
    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO NTT
    ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT Survey telescope
    VLT Survey Telescope at Cerro Paranal with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).


    ESO APEXESO/MPIfR APEX high on the Chajnantor plateau in Chile’s Atacama region, at an altitude of over 4,800 m (15,700 ft)at the Llano de Chajnantor Observatory in the Atacama desert.

    A novel gamma ray telescope under construction on Mount Hopkins, Arizona. a large project known as the Cherenkov Telescope Array, composed of hundreds of similar telescopes to be situated in the Canary Islands and Chile. The telescope on Mount Hopkins will be fitted with a prototype high-speed camera, assembled at the University of Wisconsin–Madison, and capable of taking pictures at a billion frames per second. Credit: Vladimir Vassiliev

     
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