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  • richardmitnick 7:01 am on July 24, 2017 Permalink | Reply
    Tags: ESO, ESO Messenger Issue 168   

    From ESO: Messenger Issue 168 Available in the ESOshop 

    ESO 50 Large

    European Southern Observatory

    ESO Messenger Issue 168 is available for purchase in the ESOshop

    1
    Price: € 1,99 in the ESOshop

    The latest edition of ESO’s quarterly journal, The Messenger, is now available online. Find out the latest news from ESO on topics ranging from new instruments to the latest science discoveries.

    Highlights of this edition include:

    A Long Expected Party — The First Stone Ceremony for the Extremely Large Telescope
    The Adaptive Optics Facility: Commissioning Progress and Results
    The Cherenkov Telescope Array: Exploring the Very-high-energy Sky from ESO’s Paranal Site
    Towards a Sharper Picture of R136 with SPHERE Extreme Adaptive Optics
    The VIMOS Public Extragalactic Redshift Survey (VIPERS): Science Highlights and Final Data Release

    Download The Messenger in PDF format or visit The Messenger website to subscribe and receive a free printed copy.

    See the full article here .

    Please help promote STEM in your local schools.
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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 LaSilla
    ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

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

    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.

    ALMA Array
    ALMA on the Chajnantor plateau at 5,000 metres.

    ESO E-ELT
    ESO/E-ELT to be built at Cerro Armazones at 3,060 m.

    ESO APEX
    APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert.

    Leiden MASCARA instrument, La Silla, located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    Leiden MASCARA cabinet at ESO Cerro la Silla located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

     
  • richardmitnick 8:56 pm on July 7, 2017 Permalink | Reply
    Tags: , , , , ESO, Sgr*   

    From ESO: “6. What is Sagittarius A*?” 

    ESO 50 Large

    European Southern Observatory

    27.6.2017

    The Event Horizon Telescope (EHT) and the Global mm-VLBI Array (GMVA) [see my previous post, https://sciencesprings.wordpress.com/2017/07/07/from-eso-5-how-to-build-an-earth-sized-radio-telescope/%5D have caused quite a stir with their recent observations of the supermassive black hole at the centre of the Milky Way, also known as Sagittarius A*. These observations are expected to lead to remarkable scientific results, enhancing our understanding of black holes and our theories of space and time. But just twenty years ago, astronomers didn’t know for sure that Sagittarius A* was the site of a black hole. Let’s step back in time and find out how we arrived at this point.

    In the same year, American radio astronomers Bruce Balick and Robert Brown at the National Radio Astronomy Observatory discovered a compact radio source at the very centre of the Milky Way. At radio wavelengths it’s the brightest feature in the Galactic Centre but it is fairly small.

    Back in 1974, British astronomer Sir Martin Rees proposed that supermassive black holes could live at the centres of some galaxies, such as those harbouring active galactic nuclei (AGN). Such galaxies shine incredibly brightly in many different wavelengths — as bright as 30 billion Suns or more — and they also spew out powerful jets of charged particles. Rees realised that black holes could be the cause of this energetic turmoil, a fact that is now confirmed.

    Balick and Brown thought it looked like a faint quasar, a type of AGN that was more common in the distant past. But this object was in our own cosmic backyard — just 26 000 light-years away. They dubbed it Sagittarius A*, or Sgr A* for short, because it is located in the direction of the constellation of Sagittarius. The asterisks arose because in atomic physics, excited states of atoms are denoted by asterisks — and Sgr A* is an incredibly exciting discovery.

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    Sagittarius A*, taken by NASA’s Chandra X-Ray Observatory. Ellipses indicate light echoes. Credit: NASA/CXC/Caltech/M.Muno et al.

    Over the next two decades, astronomers studied this bizarre object at different wavelengths and began to fit together the various pieces of the puzzle. As improving technology provided sharper and sharper views, they observed the commotion going on around the object. Gas and stars were whirling around it at incredible speeds — up to five million kilometres per hour — demonstrating that the object must be very small but very massive, with a staggering gravitational influence. Then, shortly after its launch in 1998, the Chandra X-ray Observatory spotted the first X-ray emission from Sgr A*. When matter is swallowed by a black hole, it emits a final “scream” of X-ray radiation before it crosses the event horizon. These X-rays can penetrate the thick clouds of gas and dust that veil the region, providing tell-tale evidence that a black hole lurks within.

    Since the mid-1990s, research teams in Germany and the USA have been meticulously tracking the orbits of stars around Sgr A*. The US team, led by Andrea Ghez at the UCLA Galactic Center Group, has been using the W. M. Keck Observatory to measure the positions of thousands of stars in the vicinity of the Galactic Centre.

    Andrea Ghez, UCLA

    Andrea’s Favorite star SO-2


    Keck Observatory, Mauna Kea, Hawaii, USA

    The German team uses ESO’s Very Large Telescope to precisely measure the orbits of 28 stars frantically speeding around Sgr A*.

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

    These dedicated groups have produced the most detailed view ever of the region surrounding Sgr A*, and in 2008 confirmed once and for all that Sgr A* is the site of a supermassive black hole.

    “Undoubtedly the most spectacular aspect of our long term study is that it has delivered what is now considered to be the best empirical evidence that supermassive black holes do really exist,” commented Reinhard Genzel, leader of the German team from the Max Planck Institute for Extraterrestrial Physics. “The stellar orbits in the Galactic Centre show that the central mass concentration of four million solar masses must be a black hole, beyond any reasonable doubt.”


    Time-lapse sequence with VLT and NTT images
    Images collected over 16 years have been assembled into a time-lapse video. The real motion of the stars has been accelerated by a factor 32 million. Credit: ESO/ R.Genzel and S. Gillessen.

    We have learned a great deal about Sgr A* over the years, as constant research has slowly revealed more and more of its secrets. Today, we know it is more than 4 million times as massive as the Sun but is extremely small, only about 40 million kilometres across — approximately equivalent to the distance from Mercury to the Sun. It is also fairly quiet for a black hole — it doesn’t emit an enormous amount of radiation, indicating that it typically doesn’t consume a lot of material. Astronomers have, however, captured blinding flares of X-rays hundreds of times brighter than the usual emissions. These are thought to be caused by the breaking apart of an asteroid falling into the black hole, or the entanglement of magnetic fields lines within the inflowing gas. Astronomers have also tracked a dust gas cloud called G2 that is in orbit around Sgr A* and imaged its closest approach in 2014. These observations, along with many more, add to our knowledge of the behaviour of this black hole and its surrounding turbulent environment.

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    This annotated composite image shows the motion of the dusty cloud G2 as it closes in on, and then passes, the supermassive black hole at the centre of the Milky Way. These observations were made with ESO’s VLT and show that the cloud appears to have survived its close encounter with the black hole and remains a compact object. Credit: ESO/A. Eckart

    But mysteries still remain about this cosmic beast at the centre of our galaxy — and about black holes in general. Sgr A* has helped cement the idea that every large galaxy hosts a supermassive black hole at its core, but astronomers are still scratching their heads about how such supermassive black holes form, and how they affect their host galaxies.

    The GMVA and the EHT teams are using Very-Long-Baseline Interferometry to image Sagittarius A* in greater detail than ever before, linking up telescopes around the world. As well as probing the tumultuous regions around the black hole, the astronomers are also looking for one of the last pieces of the puzzle — observing the event horizon. This is the radius around a singularity beyond which matter and energy cannot escape a black hole’s gravitational pull; it is literally the point of no return.

    The EHT and GMVA teams aim to observe the event horizon’s shadow. Not only will that demonstrate its existence, but measuring its shape and size will provide an unprecedented way to verify Einstein’s theory of general relativity. But of course, this is no easy task…

    This is the sixth post of a blog series following the EHT and GMVA projects. Next time, we’ll talk about the challenges involved in imaging a supermassive black hole.

    See the full article here .

    Please help promote STEM in your local schools.
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    Stem Education Coalition
    Visit ESO in Social Media-

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

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

    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

    ALMA Array
    ALMA on the Chajnantor plateau at 5,000 metres

    ESO E-ELT
    ESO/E-ELT to be built at Cerro Armazones at 3,060 m

    ESO APEX
    APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert

     
  • richardmitnick 8:30 pm on July 7, 2017 Permalink | Reply
    Tags: , , , , , ESO, GMVA-Global mm-VLBI Array, SagA*   

    From ESO: “5. How to build an Earth-sized radio telescope” 

    ESO 50 Large

    European Southern Observatory

    A black hole is an extraordinary object with extremely strong gravity, but when observed from Earth it would look like a tiny dot. To capture an image of a black hole, a telescope with extraordinarily high resolution is required. But how can such a revolutionary telescope be created?

    As we discovered in the previous post, the larger the diameter of the telescope, the better the resolution. This is true both for optical and radio telescopes, which means that a tremendously large telescope is needed to observe a small object that can barely be seen from Earth — like a black hole.

    The Atacama Large Millimeter/submillimeter Array (ALMA), which is operated in Chile by a global partnership, combines multiple antennas spread over distances from 150 metres to 16 kilometres. This allows it to simulate a single giant telescope much larger than any individual dish that could be built, achieving a resolution equivalent to up to a 16-km diameter telescope. ALMA’s resolution reaches 1/100 of 1/3600 of a degree angle — 5000 times better than the human eye!

    And yet even with such an exceptionally good “eyesight”, ALMA would need to improve its resolution 100 fold in order to capture a black hole at the centre of the Milky Way galaxy.

    To simulate a telescope with 100 times the resolution of ALMA, telescopes must be spread over a much larger area — far beyond the Chilean Andes, beyond even South America and extending to North America and Europe. Using the Very-Long-Baseline Interferometry (VLBI) technique, telescopes of several thousand kilometres in diameter can be simulated. The Event Horizon Telescope (EHT) and Global mm-VLBI Array (GMVA) both form Earth-sized telescopes that combine the observing power and the data collected by a range of telescopes across the world, including ALMA. The participating telescopes are listed below.

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    Telescopes contributing to the EHT and GMVA observations of Sagittarius A*. The connected telescopes simulate a telescope equivalent to the dimensions of the whole western hemisphere of the Earth. Credit: ESO/O. Furtak

    Event Horizon Telescope Array

    Event Horizon Telescope map

    The locations of the radio dishes that will be part of the Event Horizon Telescope array. Image credit: Event Horizon Telescope sites, via University of Arizona at https://www.as.arizona.edu/event-horizon-telescope.

    Arizona Radio Observatory
    Arizona Radio Observatory/Submillimeter-wave Astronomy (ARO/SMT)

    ESO/APEX
    Atacama Pathfinder EXperiment (APEX)

    CARMA Array no longer in service
    Combined Array for Research in Millimeter-wave Astronomy (CARMA)

    Atacama Submillimeter Telescope Experiment (ASTE)
    Atacama Submillimeter Telescope Experiment (ASTE)

    Caltech Submillimeter Observatory
    Caltech Submillimeter Observatory (CSO)

    IRAM NOEMA interferometer
    Institut de Radioastronomie Millimetrique (IRAM) 30m

    James Clerk Maxwell Telescope interior, Mauna Kea, Hawaii, USA
    James Clerk Maxwell Telescope interior, Mauna Kea, Hawaii, USA

    Large Millimeter Telescope Alfonso Serrano
    Large Millimeter Telescope Alfonso Serrano

    CfA Submillimeter Array Hawaii SAO
    Submillimeter Array Hawaii SAO

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array, Chile

    Future Array/Telescopes

    Plateau de Bure interferometer
    Plateau de Bure interferometer

    South Pole Telescope SPTPOL
    South Pole Telescope SPTPOL

    Global mm-VLBI Array


    GMVA ALMA, VLBA (eight locations in U.S.), GBT 100m (West Virginia, U.S.), IRAM 30m (Spain), OAN 40m (Spain), Max Planck Institute for Radio Astronomy 100m (Germany)

    But how does VLBI work? With ALMA, it’s relatively straightforward: each antenna receives signals from a target object and then sends them via optical fibres to a central location on site, where they are processed and combined by a dedicated supercomputer. However, when telescopes are located thousands of kilometres apart — halfway across the world from each other — it’s impossible to connect them via optical fibres to a central location and transmit such enormous volumes of data. VLBI therefore uses a different technique: the data are first recorded at each individual telescope and stored on recording devices on site. These devices are then shipped or flown back to one place and played back all together in a computer for data synthesis.

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    A schematic diagram of the VLBI mechanism. Each antenna, spread out over vast distances, has an extremely precise atomic clock. Analogue signals collected by the antenna are converted to digital signals and stored on hard drives together with the time signals provided by the atomic clock. The hard drives are then shipped to a central location to be synchronised. An astronomical observation image is obtained by processing the data gathered from multiple locations. Credit: ALMA (ESO/NAOJ/NRAO), J.Pinto & N.Lira.

    A key component of the VLBI technique are the clocks — and these are no ordinary clocks. To synthesise the data gathered simultaneously by contributing telescopes around the world, each telescope requires a clock set to the accurate time with astonishing precision. These clocks measure small differences in the arrival time of the radio waves coming from the target object to each antenna of the array. Every telescope taking part in VLBI is equipped with an extremely precise, specially-developed atomic clock — so accurate that over a period of 100 million years, each clock would be off by less than 1 second!

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    Hydrogen maser atomic clock installed at the ALMA Array Operations Site (AOS), along with the technicians who installed it. Credit: ALMA (ESO/NAOJ/NRAO), C. Padilla.

    Another key element in VLBI is the device used to record the data. The first VLBI experiments were carried out in the 1960s and used magnetic tapes to record observations, but since entering the 21st century, more and more VLBI observations have been recorded on hard drives because of their larger storage capacity and lower prices. The hard drives used in the EHT and GMVA observations are based on magnetic-disk technology and incorporate primarily low-cost PC components.

    One important aspect of such a recording device is the speed with which it records data. The faster the data recording speed, the more extensive the range of frequency signals that can be recorded, which improves the overall sensitivity of the observations. Some of the hard drives used in the EHT observations can record data at up to a total rate of 16 gigabits per second! Of course, the storage capacity of the hard drives is also important. The capacity of the hard drives ALMA used for the EHT/GMVA observations exceeds 1 petabyte (1 million gigabytes) in total.

    The dedicated supercomputer to process the recorded data is called a “correlator”. The EHT correlator was developed by the Massachusetts Institute of Technology in the US, while the GMVA correlator was developed by the Max Planck Institute for Radio Astronomy located in Bonn, Germany. The enormous amount of data obtained is firstly recorded at the telescopes around the world, and then sent to these two locations where it is read from each disk to the correlator at up to 4096 MB per second. The data is then processed by the correlator to form an astronomical image.

    The VLBI technique can use these cutting-edge technologies to form an Earth-sized telescope capable of achieving extremely high resolution. This raises the question: Can any type of celestial object be revealed in detail by VLBI observations? Unfortunately, the answer is no. Some objects will be a good target of the VLBI observations, while others will not.

    If you’ve ever used a microscope to observe a small object, you might be familiar with the experience of raising the magnification — only to see a dimmer view. The same thing happens with telescopes. Increasing the resolution means seeing an object in a view that is divided into many smaller parts. This inevitably results in decreasing the amount of light received from each part of the target object. Eventually, as the resolution increases, fainter objects becomes invisible.

    For this reason, the extraordinarily high resolution of VLBI is mainly suitable for observing bright objects. VLBI is often used to observe objects that emit intense radio waves, such as astrophysical masers (similar to the kind of lasers that we are familiar with, but at microwave wavelengths) occurring around young and old stars, and high-speed jets of gas ejected from supermassive black holes. Since a high-temperature gas disk around a supermassive black hole is thought to emit strong radio waves, the EHT and GMVA observations aim to use the VLBI technique to capture the elusive black hole at the centre of the galaxy.

    This is the fifth post of a blog series following the Event Horizon Telescope and the Global mm-VLBI Array projects. The next topic will focus on the supermassive black hole Sagittarius A* located at the centre of the Milky Way, a high-priority target object of the EHT/GMVA observations.

    See the full article here .

    Please help promote STEM in your local schools.
    STEM Icon

    Stem Education Coalition
    Visit ESO in Social Media-

    Facebook

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

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

    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

    ALMA Array
    ALMA on the Chajnantor plateau at 5,000 metres

    ESO E-ELT
    ESO/E-ELT to be built at Cerro Armazones at 3,060 m

    ESO APEX
    APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert

     
  • richardmitnick 3:54 pm on July 7, 2017 Permalink | Reply
    Tags: , ESO, Test-Bed Telescope at ESO’s La Silla Observatory in northern Chile   

    “ESO and ESA Reach Agreement to Site Test-Bed Telescope at La Silla” 

    ESO 50 Large

    European Southern Observatory

    ESA Space For Europe Banner

    European Space Agency

    7 July 2017
    Ivo Saviane
    ESO, Paranal
    Tel: +56 55243 4159
    Email: isaviane@eso.org

    Günther Sessler
    European Space Agency
    Robert-Bosch-Str. 5
    64293 Darmstadt, Germany
    Tel.: +49-6151-902432
    Fax: +49-6151-903046
    Email: gunther.sessler@esa.int

    Richard Hook
    ESO Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    1
    2
    In August 2015, ESO and the European Space Agency (ESA) signed a cooperation agreement setting the terms and conditions for mutual cooperation and the exchange of scientific research information between the two organisations. The first project to be implemented under this cooperation agreement is the deployment of a Test-Bed Telescope at ESO’s La Silla Observatory in northern Chile.

    Operating alongside a similar project in the northern hemisphere, the 56-cm Test-Bed Telescope (TBT) will act as a precursor to a full autonomous optical sensor network which will detect and track an extensive list of near-Earth objects, such as asteroids. The TBT will demonstrate the instrument’s hardware and software capabilities, such as automatic scheduling, remote real-time control, and autonomous data processing.

    See the full article here .

    Please help promote STEM in your local schools.
    STEM Icon

    Stem Education Coalition
    Visit ESO in Social Media-

    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

    ESA50 Logo large

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

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

    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

    ALMA Array
    ALMA on the Chajnantor plateau at 5,000 metres

    ESO E-ELT
    ESO/E-ELT to be built at Cerro Armazones at 3,060 m

    ESO APEX
    APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert

     
  • richardmitnick 5:12 am on June 14, 2017 Permalink | Reply
    Tags: , , , , ESO, VST Captures Three-In-One   

    From ESO: “VST Captures Three-In-One” 

    ESO 50 Large

    European Southern Observatory

    14 June 2017
    Richard Hook
    ESO Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    rhook@eso.org

    1
    Two of the sky’s more famous residents share the stage with a lesser-known neighbour in this enormous new three gigapixel image from ESO’s VLT Survey Telescope (VST). On the right lies the faint, glowing cloud of gas called Sharpless 2-54, the iconic Eagle Nebula is in the centre, and the Omega Nebula to the left. This cosmic trio makes up just a portion of a vast complex of gas and dust within which new stars are springing to life and illuminating their surroundings.

    Sharpless 2-54 and the Eagle and Omega Nebulae are located roughly 7000 light-years away — the first two fall within the constellation of Serpens (The Serpent), while the latter lies within Sagittarius (The Archer). This region of the Milky Way houses a huge cloud of star-making material. The three nebulae indicate where regions of this cloud have clumped together and collapsed to form new stars; the energetic light from these stellar newborns has caused ambient gas to emit light of its own, which takes on the pinkish hue characteristic of areas rich in hydrogen.

    Two of the objects in this image were discovered in a similar way. Astronomers first spotted bright star clusters in both Sharpless 2-54 and the Eagle Nebula, later identifying the vast, comparatively faint gas clouds swaddling the clusters. In the case of Sharpless 2-54, British astronomer William Herschel initially noticed its beaming star cluster in 1784. That cluster, catalogued as NGC 6604 (eso1218), appears in this image on the object’s left side. The associated very dim gas cloud remained unknown until the 1950s, when American astronomer Stewart Sharpless spotted it on photographs from the National Geographic–Palomar Sky Atlas.

    The Eagle Nebula did not have to wait so long for its full glory to be appreciated. Swiss astronomer Philippe Loys de Chéseaux first discovered its bright star cluster, NGC 6611, in 1745 or 1746 (eso0142). A couple of decades later, French astronomer Charles Messier observed this patch of sky and also documented the nebulosity present there, recording the object as Messier 16 in his influential catalogue (eso0926).

    As for the Omega Nebula, de Chéseaux did manage to observe its more prominent glow and duly noted it as a nebula in 1745. However, because the Swiss astronomer’s catalogue never achieved wider renown, Messier’s re-discovery of the Omega Nebula in 1764 led to its becoming Messier 17, the seventeenth object in the Frenchman’s popular compendium (eso0925).

    The observations from which this image was created were taken with ESO’s VLT Survey Telescope (VST), located at ESO’s Paranal Observatory in Chile. The huge final colour image was created by mosaicing dozens of pictures — each of 256 megapixels — from the telescope’s large-format OmegaCAM camera.

    ESO Omegacam on VST


    ESO Omegacam on VST at ESO’s Cerro Paranal observatory

    The final result, which needed lengthy processing, totals 3.3 gigapixels, one of the largest images ever released by ESO.

    3
    Highlights from huge VST nebula image


    ESOcast 111 Light: VST captures glowing celestial triplet


    Zooming in on a rich region of star formation


    Highlights from huge VST nebula image


    The Omega Nebula region seen with the VST


    The region of the Eagle Nebula seen with the VST


    The Sharpless 2-54 region seen with ESO’s VST

    See the full article here .

    Please help promote STEM in your local schools.
    STEM Icon

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

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

    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

    ALMA Array
    ALMA on the Chajnantor plateau at 5,000 metres

    ESO E-ELT
    ESO/E-ELT to be built at Cerro Armazones at 3,060 m

    ESO APEX
    APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert

     
  • richardmitnick 3:36 pm on June 13, 2017 Permalink | Reply
    Tags: 2016 Annual Report, ESO   

    From ESO: 2016 Annual Report will be available in the ESOShop 

    ESO 50 Large

    European Southern Observatory

    1
    The contents include:

    Research highlights from ESO facilities, with the latest results across many fields of astronomy stretching from high-redshift galaxies to the discovery of an Earth-mass planet in the habitable zone around Proxima Centauri, the nearest star.
    A summary of operations at ESO’s observatories in Chile.
    The latest news from the Extremely Large Telescope (ELT) and Atacama Large Millimeter/submillimeter Array (ALMA) projects.
    News about ESO staff and buildings — including the ALMA Residencia and the ESO Supernova Planetarium & Visitor Centre.

    This product will soon be available for sale in the ESOshop €4.99

    See the full article here .

    Please help promote STEM in your local schools.
    STEM Icon

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

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

    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

    ALMA Array
    ALMA on the Chajnantor plateau at 5,000 metres

    ESO E-ELT
    ESO/E-ELT to be built at Cerro Armazones at 3,060 m

    ESO APEX
    APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert

     
  • richardmitnick 2:31 pm on June 2, 2017 Permalink | Reply
    Tags: , , ESO,   

    From ESO: “Taking the First Picture of a Black Hole” 

    ESO 50 Large

    European Southern Observatory

    6.2.17
    No writer credit

    [These blog posts are in reverse order because that is how I found them. I still have not found the link to the blog itself to do a proper job.]

    4. How do Radio Telescopes work?
    23.5.2017

    Can you imagine yourself hearing only the bass of a music recording? Or only seeing objects of a particular colour? Well, in a way, you experience this every day. The human eye can only detect a narrow part of the electromagnetic spectrum: a section we call visible light. But a broad range of electromagnetic waves exist with the same nature — for example radio waves, which have much longer wavelengths than the light we can detect with our eyes. Radio wavelengths range from 1 millimetre to over 10 metres, while visible light wavelengths are only a few hundred nanometres — one nanometre is 1/10 000th the thickness of a piece of paper!

    Radio waves are not visible to us directly, but in 1867 their existence was predicted by James Clerk Maxwell. By the end of the 19th century, scientists had developed instruments that could transmit and detect electromagnetic waves at the radio end of the spectrum. A few decades later, it was discovered that these instruments could not only be used for communication, but could also be directed towards space — hidden parts of the Universe were suddenly revealed!

    The first detection of radio waves from an astronomical object was in 1932, when Karl Jansky observed radiation coming from the Milky Way.

    NRAO/Karl V Jansky VLA, on the Plains of San Agustin fifty miles west of Socorro, NM, USA

    Then came the phenomenal discovery of the cosmic microwave background [CMB] in 1964, worthy of a Nobel Prize in Physics.

    CMB per ESA/Planck

    ESA/Planck

    Soon afterwards, Jocelyn Bell Burnell observed the first pulsar with an array of radio aerials in 1967, which led to another Nobel Prize. And this was only the beginning — a dazzling array of discoveries have been made since.

    2
    This panoramic view of the Chajnantor plateau shows some of the 66 antennas of the Atacama Large Millimeter/submillimeter Array (ALMA). Credit: ESO/B. Tafreshi (twanight.org)

    But how do radio telescopes work?

    In order to detect signals from astronomical objects, every radio telescope requires an antenna and at least one receiver. They come in a variety of shapes and sizes, reflecting the need to be able to detect a great breadth of radio waves across many wavelengths.

    The antennas of most radio telescopes working at wavelengths shorter than 1 metre are paraboloidal dishes. The curved reflector concentrates incoming radio waves at a focal point. For shorter wavelengths, such as millimetre waves collected by ALMA and VLBI networks like the EHT and GMVA, the perfection of the dish’s surface is critical: any warp, bump, or dent in the parabola will scatter these tiny waves away from the focus, and valuable information is lost.

    In addition to the main dish, most radio telescopes have secondary reflectors that send the concentrated waves to receivers. These receivers select, detect and amplify the radio signals of the desired frequencies. The receiver delivers these signals in an analogue format, which is converted into a digital signal and fed into a computer. Astronomers can then stitch these signals together to create a map of the sky measured by radio brightness.

    Radio telescopes point at a radio source for hours in order to detect the faintest signals coming from the near and distant Universe. This technique is a similar to keeping the shutter of a camera open for a long exposure at night. After combining these signals with a computer, astronomers can analyse the radiation emitted by many astronomical phenomena — such as stars, galaxies, nebulae and supermassive black holes.

    3
    The view of the centre of our galaxy with a closer view of the object known as Sagittarius A*, the bright radio source that corresponds to the supermassive black hole. Credit: NRAO/AUI/NSF

    Sag A* NASA Chandra X-Ray Observatory 23 July 2014, the supermassive black hole at the center of the Milky Way

    Here’s the problem in radio astronomy: because radio wavelengths are so long, it is difficult to achieve a high resolution of the objects being observed. Even the shortest radio wavelengths observed by the largest single telescopes only result in an angular resolution slightly better than that of the unaided eye. The resolution (or degree of detail in the image) of a single telescope can be calculated by dividing the length of the radio wave by the diameter of the antenna. When this ratio is small, the angular resolution is large and therefore finer details can be observed. The larger the diameter of the telescope, the better the resolution, therefore radio telescopes tend to be much larger than telescopes suited for other, shorter wavelengths like visible light.

    The longest wavelengths, on scales of metres, pose a particular challenge because it is hard to achieve good resolution from a single dish. The largest moveable dish is the Green Bank Telescope (100 metres across).



    GBO radio telescope, Green Bank, West Virginia, USA

    Dishes that don’t move can be much, much larger. The world’s biggest radio dish is the newly-constructed Five-hundred-meter Aperture Spherical Telescope (FAST) in China: a fixed dish supported by a natural basin in the landscape.

    FAST radio telescope, now operating, located in the Dawodang depression in Pingtang county Guizhou Province, South China

    FAST can observe radio waves up to 4.3 metres in wavelength. There are also other similar dishes, such as the historic 300-metre Arecibo Observatory, which was the largest telescope for five decades until FAST was completed in 2016.

    NAIC/Arecibo Observatory, Puerto Rico, USA

    But building antennas any larger than this is not feasible, so here we reach a limit when it comes to observing at longer and longer wavelengths. But what can be improved is the angular resolution, opening the door of investigation into the finest details of the low-energy Universe.

    A Nobel Prize winning technique called interferometry opened this door: if the signals from many antennas spread over a large area are combined, then the antennas can operate together like a gigantic telescope — an array. Modern arrays usually bring the signals together at a central location in digital form using optical fibres, and then process them in a special-purpose supercomputer called a correlator.

    Event Horizon Telescope Array

    Event Horizon Telescope map

    The locations of the radio dishes that will be part of the Event Horizon Telescope array. Image credit: Event Horizon Telescope sites, via University of Arizona at https://www.as.arizona.edu/event-horizon-telescope.

    Arizona Radio Observatory
    Arizona Radio Observatory/Submillimeter-wave Astronomy (ARO/SMT)

    ESO/APEX
    Atacama Pathfinder EXperiment (APEX)

    CARMA Array no longer in service
    Combined Array for Research in Millimeter-wave Astronomy (CARMA)

    Atacama Submillimeter Telescope Experiment (ASTE)
    Atacama Submillimeter Telescope Experiment (ASTE)

    Caltech Submillimeter Observatory
    Caltech Submillimeter Observatory (CSO)

    IRAM NOEMA interferometer
    Institut de Radioastronomie Millimetrique (IRAM) 30m

    James Clerk Maxwell Telescope interior, Mauna Kea, Hawaii, USA
    James Clerk Maxwell Telescope interior, Mauna Kea, Hawaii, USA

    Large Millimeter Telescope Alfonso Serrano
    Large Millimeter Telescope Alfonso Serrano

    CfA Submillimeter Array Hawaii SAO
    Submillimeter Array Hawaii SAO

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array, Chile

    Future Array/Telescopes

    Plateau de Bure interferometer
    Plateau de Bure interferometer

    South Pole Telescope SPTPOL
    South Pole Telescope SPTPOL

    One such array is the Atacama Large Millimeter/submillimeter Array on the Chajnantor plateau in the Atacama Desert. ALMA comprises 66 high-precision antennas up to 16 kilometres apart, working together as an interferometer. The resolution of an interferometer depends not on the diameter of individual antennas, but on the maximum separation between them. Moving the antennas further apart increases the resolution.

    The signals from the antennas are brought together and processed by the ALMA correlator. The antennas work together in unison, giving ALMA a maximum resolution which is even better than that achieved at visible wavelengths by the NASA/ESA Hubble Space Telescope. This is because the maximum distance between the antennas can be very large, increasing the resolving power of the interferometer and allowing it to detect smaller details.

    The ability to link antennas over baselines of many kilometres is crucial to obtain extremely good resolution and a high degree of detail in the images. This gives astronomers the possibility to go even further than arrays like ALMA; by combining the signals from radio telescopes all across the world, the distances between the antennas can be Earth-sized — and even larger, in the case of space-based antennas like Spektr-R.

    The telescopes do not have to be physically connected; rather, the signals recorded at each telescope are later “played back” in the correlator. This technique, called very-long-baseline interferometry (VLBI), provides exquisite angular resolution and paves the way for phenomenal new discoveries — including the detailed observation of the supermassive black hole at the centre of our galaxy.

    This is the fourth post of a blog series following the Event Horizon Telescope and the Global mm-VLBI Array projects. Next time, we’ll talk about how to build an Earth-sized radio telescope.

    Global mm-VLBI Array

    3. What’s so interesting about the event horizon?
    2.5.2017

    We know that black holes are fascinating objects, capable of bending not only our minds but also reality itself. They squeeze matter into an extraordinarily miniscule space, resulting in an object with an immense gravitational pull. Around this object is a boundary beyond which nothing can escape, not even light: the event horizon. Besides attracting enormous quantities of matter, the event horizon is attracting a lot of attention from astronomers around the world. But why?

    As we discovered in the previous post, black holes are impossible to observe directly. Photons aren’t emitted, and therefore nothing reaches the astronomer’s telescope (except, of course, small amounts of Hawking radiation). But scientists can learn a lot from the bright material surrounding black holes.

    When matter comes under the gravitational spell of a black hole, material will either be sucked directly into it or will be pulled into a doomed orbit like water circling a drain. The gravitational pull near the event horizon is so strong that the matter around it reaches relativistic speeds (i.e. speeds comparable to the speed of light). The friction between the material heats it to incredibly high temperatures, turning it into glowing plasma. Close to the event horizon photons are pulled into nearly circular orbits, and this form a bright photon ring which outlines the black “shadow” of inside the event horizon itself.

    4
    Simulated image of an accreting black hole. The event horizon is in the middle of the image, and the shadow can be seen with a rotating accretion disk surrounding it. Credit: Bronzwaer/Davelaar/Moscibrodzka/Falcke/Radboud University

    Einstein’s theory of general relativity predicts the existence of event horizons around black holes. But until now, the resolution of our telescopes has not been high enough to “see” a black hole. Despite the fact that the event horizon can be millions of kilometres in diameter, black holes are elusive. They are very far away and often hidden behind significant amounts of interstellar gas and dust. At 26 000 light-years from Earth, our galaxy’s supermassive black hole — called Sagittarius A* — is just a tiny pinprick on the sky.

    By linking up different telescopes across the globe, the Event Horizon Telescope (EHT) and the Global mm-VLBI Array (GMVA) can achieve the resolution necessary to perceive the pinprick of Sagittarius A*. Without doubt, these observations are incredibly exciting. They will allow for the study of black holes in more detail — as well as acting as a test for Einstein’s theory of General Relativity.

    “Einstein’s wonderful general relativity has been around for about a hundred years now and is very unintuitive, but despite that, it has managed to overcome all tests so far,” explains Ciriaco Goddi, astronomer from the EHT. “However, these tests have not been done in such strong gravitational fields.”

    A pressing issue in physics is that the theories of general relativity and quantum mechanics seem to be fundamentally incompatible. To get to the bottom of this issue, physicists need to study the places where these theories overlap or break down. However, the conventional view is that this will not be observed at the event horizon of a supermassive black hole: quantum effects are expected to be important only near the horizon of lighter (about 10 microgram) black holes — of which we currently have no evidence for their existence. Yet some theorists argue that there will be deviations from classical general relativity close to the event horizon even for supermassive black holes, and these are potentially observable with the EHT.

    “If there is any deviation from Einstein’s predictions near the black hole, where gravitation is at its strongest, we would need a new theory of gravity,” Goddi says, “and that means that we would need to describe space and time in different terms.”

    General relativity predicts that the “shadow” of a black hole is circular, but other theories predict the shadow could be “squashed” along either the vertical axis (prolate) or the horizontal axis (oblate). Studying the shadow can therefore test general relativity as well as alternate theories of gravity. Plus, since the diameter of the black hole’s shadow is proportional to its mass, observing a black hole’s shadow may allow astronomers to directly estimate its mass.

    5
    This infographic shows a simulation of the outflow (bright red) from a black hole and the accretion disk around it, with simulated images of the three potential shapes of the event horizon’s shadow. Credit: ESO/N. Bartmann/A. Broderick/C.K. Chan/D. Psaltis/F. Ozel

    ALMA astronomer Violette Impellizzeri adds: We think that there is a supermassive black hole at the centre of every galaxy. But the inner workings of these black holes remain a mystery. However, we need to ask ourselves the question of why there is a supermassive black hole at the centre of every galaxy. And it’s become more and more clear that black holes play a fundamental role in the formation of galaxies, and how they evolved. So, the links between the black holes, the galaxies, and the Universe are vital to understand.”

    The VLBI observations with the EHT and GMVA will make phenomenal new discoveries, addressing the current and pressing problems of gravitational theory.

    This is the third post of a blog series following the EHT and GMVA projects. Next time, we’ll explore how radio telescopes work.

    2. What is a black hole?
    11.4.2017

    6

    Since no light can escape from a black hole, we can’t see them directly. But their huge gravitational influence gives away their presence. Black holes are often orbited by stars, gas and other material in tight paths that become more crowded and frantic as they’re dragged closer to the event horizon. This creates a superheated accretion disc around the black hole, which emits vast amounts of radiation of different wavelengths.

    By observing this radiation from the activity around black holes, astronomers have determined that there are two main types: stellar mass and supermassive.

    A stellar mass black hole is the corpse of a star more than about 30 times as massive as our Sun. At the end of its life, such stars violently collapse and don’t stopped collapsing until all of their constituent matter has condensed down into an unimaginably tiny space. It’s easiest to discover stellar mass black holes that are part of an X-ray binary system, where the black hole is guzzling down material from its companion star.

    7
    Artist’s impression of the formation of a stellar black hole in a binary system. Credit: ESO/L. Calçada/M.Kornmesser

    The second type is called a supermassive black hole. These gargantuan black holes are up to billions of times more massive than an average star, and how they formed is much less clear and is a matter of ongoing study. One theory proposes they formed from enormous clouds of matter that collapsed when galaxies first formed; another theory suggests that colliding stellar mass black holes can merge into one enormous object.

    Today, these supermassive monsters reside at the centres of almost every galaxy — including our own Milky Way. They exert tremendous influence on their home galaxies, especially when they gorge on gas and stars.

    8
    Artist’s impression of a gas cloud after a close approach to the black hole at the centre of the Milky Way. The star orbiting the black hole are shown, along with blue lines that mark their fast, tight orbits. Credit: ESO/MPE/Marc Schartmann

    26 000 light-years away from Earth, Sagittarius A* (Sgr A* for short) is the supermassive black hole in the hot, violent centre of the Milky Way. It’s over 4 million times more massive than our Sun, over 20 million kilometres across, and is spinning at a large fraction of the speed of light. It’s shrouded from optical telescopes by dense clouds of dust and gas, so observatories that can observe different wavelengths — either longer (such as ALMA) or shorter (X-ray telescopes) — are essential to study its properties.

    Soon, through the combined power of ALMA and other millimetre-wavelength telescopes across the globe, we may become much better acquainted with the monstrous heart of our galaxy. The Global mm-VLBI Array is currently investigating the process of how gas, dust and other material accrete onto supermassive black holes, as well as the formation of the extremely fast gas jets that flow from them. The Event Horizon Telescope, on the other hand, is working towards a different goal: imaging the shadow of the event horizon, the point of no return.

    This is the second post of a blog series following the EHT and GMVA projects. Stay tuned to find out more about why the event horizon of a black hole is so interesting!

    1. What are the Event Horizon Telescope and the Global mm-VLBI Array?
    30.3.2017

    At the centre of our galaxy lurks a cosmic monster: a supermassive black hole called Sagittarius A* with a mass about four million times that of the Sun. Its gravity is so intense that not even light can escape its pull, but if it wasn’t for its strong gravitational influence on the stars and gas around it, we would have no idea that it was there! Now, an ambitious new endeavour is underway to take a never-seen-before image, of the event horizon of the black hole itself.

    Two international collaborations of radio telescopes have linked up to create Earth-sized virtual telescopes: the Event Horizon Telescope (EHT) [above]and the Global mm-VLBI Array (GMVA) [above], working at different wavelengths. The impressive line-up of telescopes, which stretch across the globe from the South Pole to Hawaii to Europe, will work together to target the supermassive black hole at the heart of the Milky Way.

    To do this, astronomers will exploit a technique known as Very-long-baseline Interferometry (VLBI), where telescopes thousands of kilometres apart can link together and act as one. This cooperative technique can achieve a far higher resolution than any single facility could obtain on its own — a resolution 2000 times that of the NASA/ESA Hubble Space Telescope! This super-high resolution is crucial for detecting the black hole, which — despite being about 20 times bigger than the Sun — lies a long way away, over 26 000 light-years from Earth.

    9
    This infographic details the locations of the participating telescopes of the Event Horizon Telescope and the Global mm-VLBI Array. Credit: ESO/O. Furtak

    10
    ALMA’s solitude: This panoramic view of the Chajnantor Plateau shows the site of the Atacama Large Millimeter/submillimeter Array (ALMA), a place of solitude 5000 metres above sea level in the Chilean Andes. Credit: ESO/B. Tafreshi (twanight.org)

    The first groundbreaking observations will be made in April 2017: observations at 3 millimetre wavelengths will be made with the GMVA from 1–4 April 2017, and with the EHT at 1.3 millimetre wavelengths from 5–14 April 2017. The GMVA will investigate the properties of the accretion and outflow around the Galactic Centre, while the EHT will attempt to image, for the very first time, the shadow of the black hole’s event horizon.

    There is a long, hard road ahead to process the massive amounts of data that will be acquired during the observation periods, and results are expected to become available towards the end of 2017.

    The outcome of these observations is eagerly awaited by the astronomy community worldwide, as their scientific potential is incredibly exciting and the collaboration are pursuing some awesome goals. These could include testing Einstein’s theory of general relativity, which predicts a roughly circular “shadow” around the black hole. Other goals include learning about how material accretes around black holes, as well as the formation of extremely fast jets of gas that blast out from them.

    11
    Simulated images of the shadow of a black hole: General relativity predicts that the shadow should be circular (middle), but a black hole could potentially also have a prolate (left) or oblate (right) shadow. Future EHT images will test this prediction. Credit: D. Psaltis and A. Broderick.

    See the full article here .

    Please help promote STEM in your local schools.
    STEM Icon

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

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

    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

    ALMA Array
    ALMA on the Chajnantor plateau at 5,000 metres

    ESO E-ELT
    ESO/E-ELT to be built at Cerro Armazones at 3,060 m

    ESO APEX
    APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert

     
  • richardmitnick 1:30 pm on May 5, 2017 Permalink | Reply
    Tags: , , , ESO, ESOcast 106: ChileChill 9 — Lasers over Paranal   

    From ESO: “ESOcast 106: ChileChill 9 — Lasers over Paranal” 

    ESO 50 Large

    European Southern Observatory


    Watch, enjoy, learn.

    See the full article here .

    Please help promote STEM in your local schools.
    STEM Icon

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

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

    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

    ALMA Array
    ALMA on the Chajnantor plateau at 5,000 metres

    ESO E-ELT
    ESO/E-ELT to be built at Cerro Armazones at 3,060 m

    ESO APEX
    APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert

     
  • richardmitnick 8:27 am on April 25, 2017 Permalink | Reply
    Tags: ALMA Residencia, ESO, Handover   

    From ALMA via ESO: “ALMA Residencia Handed Over” 

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

    ESO

    25 April 2017
    Richard Hook
    ESO Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    rhook@eso.org

    1
    The new ALMA Residencia at the ALMA Operations Support Facility has just been handed over to the Joint ALMA Observatory. The celebration event was attended by the ALMA Board and the directors of the three executives — ESO, NAOJ and NRAO. The architects who designed the building were also present. The ALMA Residencia is the last major construction item to be delivered to the ALMA project by ESO.

    The handover of the ALMA Residencia is a landmark in the development of the Atacama Large Millimeter/submillimeter Array (ALMA). The new building will provide accommodation for ALMA staff and visitors at the ALMA Operations Support Facility (OSF), close to San Pedro de Atacama in northern Chile, just 28 kilometres away from the telescope itself. ESO is providing the Residencia, which is its final major contribution to the ALMA project.

    The design for the building was undertaken by the Finnish architects Kouvo & Partanen and was then adapted to the Chilean market by Rigotti & Simunovic Arquitectos, a Chilean architecture firm. The construction contract for the ALMA Residencia was awarded to the consortium AXIS LyD Construcciones Ltda, consisting of Constructora L y D S.A. and Axis Desarrollos Constructivos S.A. Both are Chilean companies that already had extensive experience in constructing residential buildings in the challenging environment of northern Chile. Construction began officially on 23 February 2015.

    The buildings have been designed so that the shape and colour of the exterior of this major architectural project will blend with the topography, the environment and the landscape of the ALMA site. Given the harsh desert environment, remote location and pattern of shift working (both day and night) for the ALMA staff, the Residencia has been designed to provide a pleasant on-site environment for staff and visitors who come from numerous countries worldwide.

    The Residencia has two main zones: common areas and dormitory areas. The design uses a modular concept so that more accommodation can be added if necessary. For now, there are 120 rooms extending across six buildings. The common areas feature impressive leisure facilities including a library, cafeteria, lounge, spa with gym, swimming pool, sauna and barbecue area. There is also a kitchen and an extensive dining room, with space to accommodate half of the residents in one sitting.

    The OSF, the site of the Residencia, is 2000 metres lower than the telescope itself up on the Chajnantor plateau. ALMA consists of an array of 66 high-precision radio antennas, of 12 metres and 7 metres diameter, working at millimetre and submillimetre wavelengths. The observatory began scientific observations at the end of September 2011 and studies the building blocks of stars, planetary systems, galaxies and life itself, letting astronomers address some of the deepest questions of our cosmic origins.

    See the full article here .

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    The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

    ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

    NRAO Small
    ESO 50 Large
    NAOJ

     
  • richardmitnick 12:54 pm on April 19, 2017 Permalink | Reply
    Tags: , , , , ESO, , LHS 1140b, MEarth North AZ USA, Red dwarfs   

    From ESO: “Newly Discovered Exoplanet May be Best Candidate in Search for Signs of Life” 

    ESO 50 Large

    European Southern Observatory

    19 April 2017
    Jason Dittmann
    Harvard-Smithsonian Center for Astrophysics
    Cambridge, USA
    Email: jdittmann@cfa.harvard.edu

    Nicola Astudillo-Defru
    Geneva Observatory – Université of Geneva
    Geneva, Switzerland
    Email: nicola.astudillo@unige.ch

    Xavier Bonfils
    Institut de Planétologie et d’Astrophysique de Grenoble – Université Grenoble-Alpes/CNRS
    Grenoble, France
    Email: xavier.bonfils@univ-grenoble-alpes.fr

    Richard Hook
    ESO Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    Megan Watzke
    Harvard-Smithsonian Center for Astrophysics
    Cambridge, USA
    Tel: +1 617-496-7998
    Email: mwatzke@cfa.harvard.edu

    1
    An exoplanet orbiting a red dwarf star 40 light-years from Earth may be the new holder of the title “best place to look for signs of life beyond the Solar System”. Using ESO’s HARPS instrument at La Silla, and other telescopes around the world, an international team of astronomers discovered a “super-Earth” orbiting in the habitable zone around the faint star LHS 1140.

    ESO/HARPS at La Silla

    ESO 3.6m telescope & HARPS at LaSilla

    This world is a little larger and much more massive than the Earth and has likely retained most of its atmosphere. This, along with the fact that it passes in front of its parent stars as it orbits, makes it one of the most exciting future targets for atmospheric studies. The results will appear in the 20 April 2017 issue of the journal Nature.

    The newly discovered super-Earth LHS 1140b orbits in the habitable zone around a faint red dwarf star, named LHS 1140, in the constellation of Cetus (The Sea Monster) [1]. Red dwarfs are much smaller and cooler than the Sun and, although LHS 1140b is ten times closer to its star than the Earth is to the Sun, it only receives about half as much sunlight from its star as the Earth and lies in the middle of the habitable zone. The orbit is seen almost edge-on from Earth and as the exoplanet passes in front of the star once per orbit it blocks a little of its light every 25 days.

    “This is the most exciting exoplanet I’ve seen in the past decade,” said lead author Jason Dittmann of the Harvard-Smithsonian Center for Astrophysics (Cambridge, USA). “We could hardly hope for a better target to perform one of the biggest quests in science — searching for evidence of life beyond Earth.”

    “The present conditions of the red dwarf are particularly favourable — LHS 1140 spins more slowly and emits less high-energy radiation than other similar low-mass stars,” explains team member Nicola Astudillo-Defru from Geneva Observatory, Switzerland [2].

    For life as we know it to exist, a planet must have liquid surface water and retain an atmosphere. When red dwarf stars are young, they are known to emit radiation that can be damaging for the atmospheres of the planets that orbit them. In this case, the planet’s large size means that a magma ocean could have existed on its surface for millions of years. This seething ocean of lava could feed steam into the atmosphere long after the star has calmed to its current, steady glow, replenishing the planet with water.

    The discovery was initially made with the MEarth facility, which detected the first telltale, characteristic dips in light as the exoplanet passed in front of the star. ESO’s HARPS instrument, the High Accuracy Radial velocity Planet Searcher, then made crucial follow-up observations which confirmed the presence of the super-Earth. HARPS also helped pin down the orbital period and allowed the exoplanet’s mass and density to be deduced [3].

    2
    On a dramatic ridge in the Coronado National Forest, the MEarth-North observatory is housed in single enclosure with a roll-off roof on Mount Hopkins, AZ, USA

    The astronomers estimate the age of the planet to be at least five billion years. They also deduced that it has a diameter 1.4 times larger than the Earth — almost 18 000 kilometres. But with a mass around seven times greater than the Earth, and hence a much higher density, it implies that the exoplanet is probably made of rock with a dense iron core.

    This super-Earth may be the best candidate yet for future observations to study and characterise its atmosphere, if one exists. Two of the European members of the team, Xavier Delfosse and Xavier Bonfils both at the CNRS and IPAG in Grenoble, France, conclude: “The LHS 1140 system might prove to be an even more important target for the future characterisation of planets in the habitable zone than Proxima b or TRAPPIST-1. This has been a remarkable year for exoplanet discoveries!” [4,5].

    In particular, observations coming up soon with the NASA/ESA Hubble Space Telescope will be able to assess exactly how much high-energy radiation is showered upon LHS 1140b, so that its capacity to support life can be further constrained.

    Further into the future — when new telescopes like ESO’s Extremely Large Telescope are operating — it is likely that we will be able to make detailed observations of the atmospheres of exoplanets, and LHS 1140b is an exceptional candidate for such studies.

    Notes

    [1] The habitable zone is defined by the range of orbits around a star, for which a planet possesses the appropriate temperature needed for liquid water to exist on the planet’s surface.

    [2] Although the planet is located in the zone in which life as we know it could potentially exist, it probably did not enter this region until approximately forty million years after the formation of the red dwarf star. During this phase, the exoplanet would have been subjected to the active and volatile past of its host star. A young red dwarf can easily strip away the water from the atmosphere of a planet forming within its vicinity, leading to a runaway greenhouse effect similar to that on Venus.

    [3] This effort enabled other transit events to be detected by MEarth so that the astronomers could nail down the detection of the exoplanet once and for all.

    [4] The planet around Proxima Centauri (eso1629) is much closer to Earth, but it probably does not transit its star, making it very difficult to determine whether it holds an atmosphere.

    [5] Unlike the TRAPPIST-1 system (eso1706), no other exoplanets around LHS 1140 have been found. Multi-planet systems are thought to be common around red dwarfs, so it is possible that additional exoplanets have gone undetected so far because they are too small.

    More information

    This research was presented in a paper entitled A temperate rocky super-Earth transiting a nearby cool star, by J. A. Dittmann et al. to appear in the journal Nature [link is above in image caption] on 20 April 2017.

    The team is composed of Jason A. Dittmann (Harvard Smithsonian Center for Astrophysics, USA), Jonathan M. Irwin (Harvard Smithsonian Center for Astrophysics, USA), David Charbonneau (Harvard Smithsonian Center for Astrophysics, USA), Xavier Bonfils (Institut de Planétologie et d’Astrophysique de Grenoble – Université Grenoble-Alpes/CNRS, France), Nicola Astudillo-Defru (Observatoire de Genève, Switzerland), Raphaëlle D. Haywood (Harvard Smithsonian Center for Astrophysics, USA), Zachory K. Berta-Thompson (University of Colorado, USA), Elisabeth R. Newton (MIT, USA), Joseph E. Rodriguez (Harvard Smithsonian Center for Astrophysics, USA), Jennifer G. Winters (Harvard Smithsonian Center for Astrophysics, USA), Thiam-Guan Tan (Perth Exoplanet Survey Telescope, Australia), José-Manuel Almenara (Institut de Planétologie et d’Astrophysique de Grenoble – Université Grenoble-Alpes/CNRS, France; Observatoire de Genève, Switzerland), François Bouchy (Aix Marseille Université, France), Xavier Delfosse (Institut de Planétologie et d’Astrophysique de Grenoble – Université Grenoble-Alpes / CNRS, France), Thierry Forveille (Institut de Planétologie et d’Astrophysique de Grenoble – Université Grenoble-Alpes/CNRS, France), Christophe Lovis (Observatoire de Genève, Switzerland), Felipe Murgas (Institut de Planétologie et d’Astrophysique de Grenoble – Université Grenoble-Alpes / CNRS, France; IAC, Spain), Francesco Pepe (Observatoire de Genève, Switzerland), Nuno C. Santos (Instituto de Astrofísica e Ciências do Espaço and Universidade do Porto, Portugal), Stephane Udry (Observatoire de Genève, Switzerland), Anaël Wünsche (CNRS/IPAG, France), Gilbert A. Esquerdo (Harvard Smithsonian Center for Astrophysics, USA), David W. Latham (Harvard Smithsonian Center for Astrophysics, USA) and Courtney D. Dressing (Caltech, USA).

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

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

    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

    ALMA Array
    ALMA on the Chajnantor plateau at 5,000 metres

    ESO E-ELT
    ESO/E-ELT to be built at Cerro Armazones at 3,060 m

    ESO APEX
    APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert

     
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