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  • richardmitnick 9:52 pm on February 15, 2019 Permalink | Reply
    Tags: "Space Cow Mystifies Astronomers", , , , , Could we be witnessing a dying star giving birth to an X-ray engine?, , ESOblog,   

    From ESOblog: “Space Cow Mystifies Astronomers” 

    ESO 50 Large

    From ESOblog

    1
    Science Snapshots – ALMA

    Could we be witnessing a dying star giving birth to an X-ray engine?

    15 February 2019

    One night in June 2018, telescopes spotted an extremely bright point of light in the sky that had seemingly appeared out of nowhere. Observations across the electromagnetic spectrum, made using telescopes from around the world, suggest that the light is likely to be the explosive death of a star giving birth to a neutron star or black hole. If so, this would be the first time ever that this has been observed. We find out more from Anna Ho, who led a team that used a variety of telescopes to figure out what exactly this mysterious object — classified as a transient and nicknamed The Cow — is.

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    Anna Ho

    Q. What is a transient, and why it is interesting to study them?

    A. The night sky appears calm but it is actually incredibly dynamic, with stars exploding in distant galaxies, visible through our telescopes as flashes of light. The word “transient” refers to a short-lived phenomenon in the night sky, which could be the explosion of a dying star, a tidal disruption event, or a flare from a star in the Milky Way. And there are probably many other types of transients out there that we have not even discovered!

    Q. So given that transients are sudden phenomena that you can’t predict, how can you possibly plan for studying them?

    A. It’s kind of a case of reacting to their appearance. In the past few years, we’ve entered this amazing new era of astronomy where telescopes can map out the entire sky every night. By comparing tonight’s map to last night’s map, we can see exactly what has changed over the previous 24 hours. The transients I study are very short-lived explosions — lasting between a few hours and a few months — so when an interesting one happens, we have to drop everything and react. Luckily I love my research enough to do this!

    It is only by using lots of different telescopes that we can really get a full picture of a transient.

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    ALMA and Very Large Array (VLA) images of the mysterious transient, The Cow.
    Credit: Sophia Dagnello, NRAO/AUI/NSF; R. Margutti, W.M. Keck Observatory; Ho, et al.

    NRAO/Karl V Jansky Expanded Very Large Array, on the Plains of San Agustin fifty miles west of Socorro, NM, USA, at an elevation of 6970 ft (2124 m)

    Q. In June 2018, you observed an unusual transient that was named AT2018cow, or The Cow. Can you describe this phenomenon? What made it so remarkable?

    A. One night, astronomers saw a point of light in the sky that had not been there before: a new transient! The Cow was particularly special for two reasons: firstly, it was VERY bright, and secondly, it had achieved that brightness VERY quickly. This was exciting, because usually if a transient appears very quickly, it is not so bright, and a very bright transient takes a long time to become bright. So we realised immediately that this was something strange.

    Q. You chose to study this transient with two millimetre telescopes: the Submillimeter Array (SMA) and ALMA (Atacama Large Millimeter/Submillimeter Array). What do millimetre telescopes offer over other telescopes?

    CfA Submillimeter Array Mauna Kea, Hawaii, USA, Altitude 4,080 m (13,390 ft)

    A. In the early stages of a transient (in its first few weeks of existence), we can see the shockwave emitted by an explosion by capturing light at millimetre wavelengths — this is exactly what SMA and ALMA can see. In particular, thanks to ALMA we were able to learn that in the case of The Cow, the shockwave was travelling at one-tenth of the speed of light, that it is very energetic, and that it is travelling into a very dense environment.

    We also used the Australia Telescope Compact Array to look at light from the transient with longer wavelengths. It is only by using lots of different telescopes that we can really get a full picture of a transient.

    CSIRO Australia Compact Array, six radio telescopes at the Paul Wild Observatory, is an array of six 22-m antennas located about twenty five kilometres (16 mi) west of the town of Narrabri in Australia.

    By combining ALMA data with publicly available X-ray data, we were also able to conclude that there must be some ongoing energy production — a kind of continuously-running “engine” at the heart of the explosion. This could be an accreting black hole or a rapidly-spinning neutron star with a strong magnetic field (a magnetar). If The Cow does turn out to have either of these at its centre, it would be very exciting, since it would be the first time that astronomers have witnessed the birth of a central engine.

    Q. It seems that nobody’s quite sure what The Cow is. Why is there so much uncertainty still surrounding this object?

    A. It’s because the combination of The Cow’s properties is so unusual. It’s like that parable of the blind man and the elephant — where several blind men each feel a different part of an elephant and come to different conclusions about what it might look like. If you look at the visible light from The Cow, you might conclude that it is a tidal disruption event. On the other hand, if you look at the longer-wavelength light you see the properties of the shockwave and the density of the surrounding matter, and might conclude that it’s a stellar explosion. It’s incredibly difficult to reconcile all of the properties into one big picture.

    4
    Artist’s impression of a cosmic blast with a “central engine,” such as that suggested for The Cow. At the moment, the central engine is surrounded by dust and gas.
    Credit: Bill Saxton, NRAO/AUI/NSF

    Q. How will you find out what The Cow really is?

    A. Right now, the heart of the explosion is shrouded in gas and dust so it’s difficult to see it. Over the next months, this gas and dust will expand out into space, becoming thinner and more transparent, and allowing us to peer inside. When we are able to see into that central engine, we will be able to learn more about what it there, whether it’s a black hole, a neutron star, or something else entirely.

    Q. What do you think The Cow is, and why?

    A. Personally, I think it’s most likely to be a stellar explosion. Our ALMA observations enabled us to measure the surrounding environment to be incredibly dense — 300 000 particles per cubic centimetre! This kind of density is typical of a stellar explosion. Some people suggest it’s a tidal disruption event, but I think this would be difficult to explain. That said, I’m far from an expert on tidal disruption, so I look forward to hearing more from theorists on how to reconcile that model with our observations.

    Q. So what are the implications of this discovery? What does The Cow teach us about transients?

    A. From my perspective, The Cow is incredibly exciting for two reasons. One is astrophysical — what it can teach us about the death of stars. We think we’ve witnessed the birth of a central engine, an accreting black hole or a spinning neutron star, for the first time.

    The second reason is technological — we learned that this is a member of a whole class of explosions that in their youth emitted bright light at millimetre wavelengths. In the past, millimetre observatories like ALMA were rarely used to study cosmic explosions, but this study has opened the curtain on a new class of transients that are prime targets for millimetre observatories. Over the next few years, we hope to discover many more members of this class, and now we know that we should use millimetre telescopes to study them!

    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,

    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.

    ALMA Array
    ALMA on the 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 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)

    ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

    ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

    ESO ExTrA telescopes at Cerro LaSilla at an altitude of 2400 metres

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  • richardmitnick 4:33 pm on February 14, 2019 Permalink | Reply
    Tags: , , , , , ESOblog, High-z Supernova Search Team, Supernova Cosmology Project at Lawrence Berkeley National Laboratory,   

    From ESOblog: “A Nobel Achievement (part II)” Bruno Leibundgut 

    ESO 50 Large

    From ESOblog

    1

    3
    Bruno Leibundgut

    8 February 2019
    People@ESO

    In 2011, the High-z Supernova Search Team won the Nobel Prize in Physics for the discovery that the expansion of the Universe is accelerating. Bruno Leibundgut, ESO’s Very Large Telescope Programme Scientist, was one of two ESO scientists who contributed to this extraordinary discovery, with the other being Jason Spyromilio. Bruno tells us the story of this game-changing piece of astronomical research in the second post in a two-part series about this prize-winning discovery.

    Also see: A Nobel Achievement (part I) https://sciencesprings.wordpress.com/2019/02/01/from-esoblog-a-nobel-achievement-part-i-bruno-leibundgut/

    At the beginning of the 1990s, the biggest question in astronomy was probably: what is the future of the Universe? Is it going to collapse? Or will it expand forever? Nobody knew.

    At the time many astronomers were looking at type Ia supernovae, which are the extremely bright explosions that occur when two stars in a binary system merge. This type of supernova always produces a similar amount of light, so we know how far away they are by how bright they look from Earth. And because they are so bright, we can often see supernovae even when they are really distant. This all means that we can use type Ia supernovae to find out about the past and future of the Universe; by comparing the apparent distance predicted by their brightness to their actual distance, it is possible to determine whether the expansion of the Universe has decelerated since the explosion occurred.

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    Artist´s impression of a binary system before and after merging to create a supernova. Credit: ESO

    I was working as part of a team that was trying to do just that. In 1995 and 1996, team member Adam Riess collected our observations on the brightness of ten distant supernovae, and the and team leader Brian Schmidt compared their distances and their brightnesses.

    They came up with the result that the expansion of the Universe was not decelerating. This was very surprising as we had expected that all the matter in the Universe is pulled together by gravity, leading to a decelerating expansion. But then in December 1997, Adam said to us: “Those distant supernovae are too far away. It’s like something has pushed them away from us. Could it be that the expansion of the Universe is actually accelerating?”

    This sparked a heated discussion — via email as the team was distributed all over the world! Brian was in Australia, Adam was on the west coast of the US, we had people on the east coast, we had people in Hawaii. And I was in Germany working with the data from the ESO telescopes. We would send an email in the evening and get up in the morning to find out about a number of other issues. But in the end, Adam and Brian could prove that there was no obvious mistake in the analysis. [Saul Perlmutter heads the Supernova Cosmology Project at Lawrence Berkeley National Laboratory at the same time with the same goal. He shared the Nobel prize with Adam Riess and Brian Schmidt.]


    In this much sped-up artist´s impression showing a collection of distant galaxies, the occasional supernova can be seen. Each of these exploding stars briefly rivals the brightness of its host galaxy. Credit: ESO/L. Calçada

    So, we decided we would have to submit a paper presenting our results, and we were sure that someone else would tell us what was wrong. But this didn’t happen. There were some people who didn’t believe us, but they were in the minority, and they couldn’t prove we were wrong.

    I’m not sure we were fully aware at the time what a big deal this discovery was. The fact that the expansion of the Universe is accelerating means that there must be some invisible “thing” in the Universe driving the expansion, causing the objects in it to flow apart faster than we would expect even for a universe without matter. The calculations tell us that this “thing” must be about three quarters of the energy content of the Universe. In a way, this was like discovering three quarters of the Universe that people had no idea existed.

    We were helped by another discovery made around the same time, related to the Cosmic Microwave Background (CMB).

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    CMB per ESA/Planck

    ESA/Planck 2009 to 2013

    People were using the CMB to study the geometry of the Universe. The tiny temperature fluctuations in the CMB indicated that the geometry of spacetime is flat, which requires a specific amount of matter and energy. Einstein’s famous equation E=mc2 tells us that mass (matter) and energy are equivalent. But determinations of the amount of matter and energy known to exist in the Universe made up just 25% of the amount required by a flat Universe. In other words, 75% of the matter and energy was missing.

    This value matched perfectly with our discovery of the extra energy component that makes up three quarters of the matter/energy content of the Universe. It was the combination of the two discoveries at almost the same time that convinced most people.

    This new component is now called dark energy. But more than twenty years later, we still have no idea what dark energy actually is! There is no physical explanation for it, but astronomers all over the world are working to find one.

    This discovery certainly affected my career. All of a sudden, I became one of the best-known observational cosmologists in Europe, which came with its pros and cons.

    As one of only two Europeans on the High-z Supernova Search Team, I got invited to many, many conferences here in Europe to present the result, and was asked to write major review papers on it. This took a lot of time out of my research.

    And then in 2011, Adam Riess and Brian Schmidt won the Nobel Prize in Physics for this research — they each won a quarter, and Saul Perlmutter of the Supernova Cosmology Project won the other half. We all went along for the Nobel Prize celebrations, which was an amazing experience.

    4
    The High-z Supernova Search Team just after the Nobel Prize award ceremony. Bruno stands on the right and Jason Spyromilio on the left of the back row.
    Credit: Nicolas Suntzeff

    But in the long run, I decided that I didn’t want to be part of large collaborations any more. The High-z Supernova Search Team wasn’t that big — around 25 people — but there were still so many teleconferences and meetings. I just felt tired of all that. I wanted to do things that I could be recognised for directly, rather than being a member of a team. I wanted to create something that people could recognise as coming from me.

    I’m still doing cosmology, though not the same type any more. That kind of research now requires large teams of hundreds of people. I’ve started to pick smaller problems again — things that I can do with students, to solve some of the smaller questions that we have about supernovae. It’s interesting to come from a big stage, from a place where the whole world pays attention to you, to go back to smaller problems that are not necessarily seen by everybody, and maybe not even seen as interesting by a lot of people. But that’s OK.

    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,

    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.

    ALMA Array
    ALMA on the 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 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)

    ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

    ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

    ESO ExTrA telescopes at Cerro LaSilla at an altitude of 2400 metres

     
  • richardmitnick 1:34 pm on February 1, 2019 Permalink | Reply
    Tags: , , , , , Dark Energy and the expansion of the universe, , ESOblog, The High-Z Supernova Search Team, The Supernova Cosmology Project   

    From ESOblog: “A Nobel Achievement (part I)” Bruno Leibundgut 

    ESO 50 Large

    From ESOblog

    1
    People@ESO

    How it feels to be part of a team that makes a Nobel Prize-winning discovery.

    Just over seven years ago, the Nobel Prize in Physics was awarded “for the discovery of the accelerating expansion of the Universe”. ESO’s Very Large Telescope Programme Scientist, Bruno Leibundgut, was part of the team that won. In the first post of a two-part series about Bruno’s career, we ask him about his experience at the Nobel Prize celebrations. The second post will be released next Friday and will focus on the science behind the prize.

    Q. First of all, could you tell us about the amazing discovery that gained your team a Nobel Prize in Physics?

    Twenty years ago, it was known that the Universe is expanding, that other galaxies are moving away from us and from each other. But the big question at the time was: will the expansion continue forever or will it stop at some point in the future, causing the Universe to collapse? Our team — the High-z Supernova Search Team — was trying to answer this question when we were surprised to find that distant objects were further away than expected in a freely expanding Universe.
    _________________________________________________
    The High-Z Supernova Search Team was an international cosmology collaboration which used Type Ia supernovae to chart the expansion of the universe. The team was formed in 1994 by Brian P. Schmidt, then a post-doctoral research associate at Harvard University, and Nicholas B. Suntzeff, a staff astronomer at the Cerro Tololo Inter-American Observatory (CTIO) in Chile. The original team first proposed for the research on September 29, 1994 in a proposal called A Pilot Project to Search for Distant Type Ia Supernova to the CTIO Inter-American Observatory. The original team as co-listed on the first observing proposal was: Nicholas Suntzeff (PI); Brian Schmidt (Co-I); (other Co-Is) R. Chris Smith, Robert Schommer, Mark M. Phillips, Mario Hamuy, Roberto Aviles, Jose Maza, Adam Riess, Robert Kirshner, Jason Spiromilio, and Bruno Leibundgut. The original project was awarded four nights of telescope time on the CTIO Victor M. Blanco Telescope on the nights of February 25, 1995, and March 6, 24, and 29, 1995.


    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet

    The pilot project led to the discovery of supernova SN1995Y. In 1995, the HZT elected Brian P. Schmidt of the Mount Stromlo Observatory which is part of the Australian National University to manage the team.

    The team expanded to roughly 20 astronomers located in the United States, Europe, Australia, and Chile. They used the Victor M. Blanco telescope to discover Type Ia supernovae out to redshifts of z = 0.9. The discoveries were verified with spectra taken mostly from the telescopes of the Keck Observatory, and the European Southern Observatory.

    In a 1998 study led by Adam Riess, the High-Z Team became the first to publish evidence that the expansion of the Universe is accelerating (Riess et al. 1998, AJ, 116, 1009, submitted March 13, 1998, accepted May 1998). The team later spawned Project ESSENCE led by Christopher Stubbs of Harvard University and the Higher-Z Team led by Adam Riess of Johns Hopkins University and Space Telescope Science Institute.

    In 2011, Riess and Schmidt, along with Saul Perlmutter of the Supernova Cosmology Project, were awarded the Nobel Prize in Physics for this work.

    The Supernova Cosmology Project is one of two research teams that determined the likelihood of an accelerating universe and therefore a positive cosmological constant, using data from the redshift of Type Ia supernovae.[1] The project is headed by Saul Perlmutter at Lawrence Berkeley National Laboratory, with members from Australia, Chile, France, Portugal, Spain, Sweden, the United Kingdom, and the United States.

    The work for this project was carried out at the Wm Keck Observatory, Maunakea, Hawai’i, USA


    Keck Observatory, Maunakea, Hawaii, USA.4,207 m (13,802 ft), above sea level, showing also NASA’s IRTF and NAOJ Subaru

    This discovery was named “Breakthrough of the Year for 1998” by Science Magazine and, along with the High-z Supernova Search Team, the project team won the 2007 Gruber Prize in Cosmology and the 2015 Breakthrough Prize in Fundamental Physics. In 2011, Perlmutter was awarded the Nobel Prize in Physics for this work, alongside Adam Riess and Brian P. Schmidt from the High-z team.
    _________________________________________________
    It appeared that they were somehow being pushed away…we had found that the Universe was not only expanding — it was accelerating! This means that not only is there normal matter in the Universe, but also another component that we cannot see, that pushes space apart. This unknown entity is now called dark energy.

    Dark Energy Survey


    Dark Energy Camera [DECam], built at FNAL


    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet

    Q. Half of the Nobel Prize went jointly to your team members Adam Riess and Brian Schmidt. Why were they the ones to receive the prize, and what was your role in the team?

    A. Brian Schmidt was the team leader; he formed the team in 1994. Adam Riess collected most of the data in 1995 and 1996, which included information about the brightness of ten distant supernovae. Brian asked me to join the team to bring some ESO observing time…it’s hard to define what exactly every team member’s contribution was, but I worked a lot with the data that we gathered using ESO telescopes. I was also part of the discussions about the implications of the data.

    2
    Bruno Leibundgut at the Nobel celebration in Stockholm in 2011. Bruno was part of the winning team of the Nobel Prize in Physics, awarded for the discovery that the Universe is expanding at an accelerating rate. Credit: Jutta Tiemann

    Q. Can you tell us about your week in Stockholm, where the Nobel Prize was awarded? What did you do while you were there? What was the atmosphere like?

    A. It was an extremely full week! Aside from the award ceremony itself in Stockholm’s National Theatre, there was also a Nobel concert, attended by the Queen of Sweden, to which we were invited by the Nobel Prize winners. There were so many receptions and celebrations throughout the week, and it was even busier for the winners!

    The winners, Adam Riess and Brian Schmidt, were very kind. They used their prize money to invite all of the team members, plus their partners, to the ceremony for the whole week. We even got to stay in the same fancy hotel as they did: the Grand Hotel in Stockholm.

    Lots of our colleagues were there, including the other winning team, the Supernova Cosmology Project. The two teams had been in strong competition, because we were working towards the same result at the same time, sometimes even using the same instruments. That week, though, the competition fell away, because we were all winners and we had all contributed to this discovery. It was wonderful because we had the chance to discuss a lot, to talk about past experiences, things that occurred during the experiments. There was a lot of reminiscing and a lot of fun.

    Q. What was the most special moment for you during the celebrations?

    A. There were plenty of special moments, as the event is an incredible celebration of scientific research. One moment that stands out took place at the post-ceremony party. I bumped into Brian Schmidt, congratulated him and said: “Look, you’re a different person now, a certified genius!” He turned to me and said, “But Bruno, nothing will change between us.” And it’s true — now we meet less than once a year, but our relationship remains close.

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    ESO 1-metre Schmidt Telescope image of the Tarantula Nebula in the Large Magellanic Cloud. Supernova 1987A is clearly visible as the very bright star slightly to the right of the centre.
    Credit: ESO

    3
    The ESO 1-metre Schmidt telescope at La Silla began its service life in 1971 using photographic plates to take wide-field images of the southern sky.

    Q. What current questions in astronomy do you wish you knew the answers to?

    A. Oh, there are so, so many! It would be wonderful to understand more about dark energy. What is it? Where does it come from? What’s the physical basis for it? We’re pretty much searching in the dark — literally! We haven’t really made progress in this field over the last ten years but we hope that with the Extremely Large Telescope [below], we will be able to shed light on this mystery.

    Q. What do you love most about astronomy?

    A. I love the detective work: the fact that you can work away at a problem for years, debate it with friends, look at it from different angles, and then suddenly you have a breakthrough and see something you’ve never seen before. I also love the ingenuity: the way that we have to devise our experiments without being able to touch our subjects. We can’t modify the sky or the stars: we just have to take them as they are, and employ our physical intuition to understand what we see.

    One of the things I have focused on over the course of my career is Supernova 1987A, which I had the chance to see in the sky with my own eyes. Every time we look at it with the Very Large Telescope or the Hubble Space Telescope, we find something else unexpected — it’s amazing to be continually mesmerised by what this single object is doing. It’s beautiful because it’s an object that changes on the same timescale as a human lifetime, and it exploded at the beginning of my career. I look forward to seeing what else we can learn about it.

    Sgr A* from ESO VLT

    Biography Bruno Leibundgut

    After a Physics degree and a PhD in Astronomy, Swiss astronomer Bruno Leibundgut found himself in the United States for two postdoctoral positions. Returning to Europe in 1993, Bruno started working at ESO in a group that defined how the VLT would be operated. After a couple of years he became Deputy VLT Programme Scientist, then in 1999 moved on to building up the data quality control group, connected to the archive. Bruno was Head of Office for Science for eight years, then Director for Science for six years, before closing the circle by becoming VLT Programme Scientist four years ago.

    People@ESO shares stories of the people at ESO who are driving forward the world’s most advanced ground-based telescopes. Find more blog posts from guest bloggers and interviews with astronomers here on the ESOblog.

    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-

    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,

    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.

    ALMA Array
    ALMA on the 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 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)

    ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

    ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

    ESO ExTrA telescopes at Cerro LaSilla at an altitude of 2400 metres

     
  • richardmitnick 2:15 pm on January 26, 2019 Permalink | Reply
    Tags: , , , Black tape, , ESOblog, SPHERE Adaptive Optics on the VLT, Spiders   

    From ESOblog: “Warming up spiders on the Very Large Telescope” 

    ESO 50 Large

    From ESOblog

    25 January 2019

    1
    HighTech ESO

    Never underestimate the value of black tape.

    After years of planning, in 2014 ESO’s Very Large Telescope welcomed the planet-hunting SPHERE instrument.

    ESO SPHERE extreme adaptive optics system and coronagraphic facility on the extreme adaptive optics system and coronagraphic facility on the VLT MELIPAL UT3, Cerro Paranal, Chile, with an elevation of 2,635 metres (8,645 ft) above sea level

    Ever since, SPHERE has enabled scientists to carry out ground-breaking astronomical research, including investigating how planetary systems are formed. But SPHERE experienced some teething problems from the very beginning. When experiencing little or no wind, the images it produced were of a much poorer quality than when the wind blew with more force. At first, this paradox baffled engineers, but they quickly donned their detective hats to figure out what exactly was going on. ESO’s Markus Kasper tells us how he worked as part of a team of experts to understand and solve this problem.

    Q. Other than being a telescope-detective, what is your role at ESO?

    A. My official title is “Adaptive Optics Scientist”, although “telescope-detective” sounds good as well! In reality, I sit at the meeting point between adaptive optics, instrumentation and astronomy. Adaptive optics is a relatively new astronomical technique where deformable mirrors on telescopes correct in real-time for the distortion of light caused by the turbulence in Earth’s atmosphere. My role mostly involves work on instruments, especially for the Very Large Telescope (VLT), but I also dabble in astronomy, in particular in the fields of exoplanets and star formation.

    Q. What was the problem you noticed when SPHERE was first switched on, and what were the clues that led you to understand this problem?

    A. We noticed that SPHERE’s adaptive optics system didn’t perform well on a significant fraction of nights, resulting in poor quality images. Clue one was the realisation that the nights it performed badly were nights that had especially low wind conditions. This was particularly annoying because such gentle conditions usually lead to the sharpest images, as the light is not blurred and distorted much on its way through the atmosphere. So on the nights where we should have been getting fantastic images, we were actually getting very poor ones.

    Many telescopes, including most of ESO’s telescopes, host a large secondary mirror supported by mechanical struts that are rather imaginatively called “spiders”. When the spiders are colder than the surrounding air, the air cools down when it comes into contact with them. The density of air increases as it cools, which means that its refractive index increases. This results in light becoming distorted as it moves through the cold air. Clue two was that the VLT’s secondary mirror was indeed supported by such a spider.

    Putting the two clues together, we realised that the telescope’s spider was causing SPHERE’s adaptive optics to perform poorly. Most wavefront sensors used in adaptive optics systems can’t measure and correct for the distortion caused by the cooler spiders interacting with the warmer air, so the resulting image is degraded. This was the first time ever that anyone had realised this image-blurring effect of the cool spiders, so we had free reign to call it whatever we wanted. At first, we nicknamed it the “Mickey Mouse Effect” because it often led to images with two side lobes that looked like Mickey Mouse’s ears! Upon further consideration, we decided that naming it the “Low Wind Effect (LWE)” sounded a little more professional…

    It is only now, in retrospect, that we realise this effect is something that has severely hampered the performance of adaptive optics systems not only at Paranal Observatory, but around the world.

    2
    A demonstration of how the Low Wind Effect (LWE) affects astronomical images. Credit: Milli et al.

    Q. Why is it called the “Low Wind Effect”?

    A. It seems a bit counter-intuitive but this effect occurs when the wind blows gently, because the lower the wind speed, the longer one bit of air is in contact with the spider. This means that more heat is transferred from the air to the spider, and so the air cools down more. When the wind is strong, air is quickly blown away from the spider, so doesn’t have much time to transfer heat.

    It’s the same when you touch a very cold object. If you have your hand on it for just a fraction of a second, you barely notice the cold because your skin has little time to transfer heat. But holding your hand there for several seconds becomes painfully cold because your skin loses so much heat to the object.

    3
    APEX helps astronomers observe the cold and distant Universe. APEX’s secondary mirror is visible at the top of this image, supported by a spider.
    Credit: F. Montenegro-Montes/ESO/APEX (MPIfR/ESO/OSO)

    Q. So you’d successfully figured out what the problem was. How did you then go about finding a solution?

    A. The main reason why the spider was colder than the air was because it was constantly emitting energy into the night sky. The same effect cools down things that are outside at night below the dew point, leading to morning dew.

    We figured that the Low Wind Effect wouldn’t be possible if the telescope spider was the same temperature as the air. So the solution was simply a matter of us carefully analysing how air is cooled down by a colder structure that it comes into contact with and then working out how to keep the temperature of the spider as close to the temperature of the air as possible.

    Sadly the solution wasn’t as simple as just wrapping the spider in a blanket. Instead, we considered several other strategies to reduce the problem, including actively heating the spider, correcting the resultant blurring, and attacking the root cause of the problem by preventing the spider from being able to emit energy.

    In the end, we went for this third option, which I suppose is actually somewhat similar to wrapping the spider in a blanket! The old spider surface very efficiently emitted radiation, so we decided to cover it with a new surface that doesn’t radiate efficiently. The solution involved finding a tape coated with a special material with the right properties and wrapping this tape around the spider arms.

    It sounds like a cliche but I would like to highlight that this solution really was a team effort! Three groups of researchers — one from the SPHERE consortium, one from Paranal and one from ESO HQ — worked together to understand the effect, and develop mitigation strategies. The fact that this fix to the world’s most advanced optical instrument involved something as simple as tape is of course a bit funny, but — again to sound a bit more professional — I should mention that this tape is really unique and is also used on spacecraft.

    4
    One of the four spider arms with the top beam covered with the new tape and the bottom beam still uncovered. Credit: Milli et al.

    Q. And has the solution work as well as you’d hoped it would?

    A. The solution was very effective. Ever since we implemented it, we’ve rarely observed the Low Wind Effect, and when it has occurred during really exceptionally low wind speed conditions, the image degradation was not bad at all compared to how it was previously. This is very good news not only for SPHERE, but for all instruments on Paranal that make use of adaptive optics.

    The VLT is made up of four Unit Telescopes (UTs). The tape was first applied to the spider supporting the secondary mirror of UT3, home to SPHERE, and proved so effective that has now been applied to UT4, which hosts other adaptive optics instruments. Designers of the future Extremely Large Telescope also plan to use this method on parts of its structure. Looks like I need to go and invest in some more tape!

    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,

    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.

    ALMA Array
    ALMA on the 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 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)

    ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

    ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

    ESO ExTrA telescopes at Cerro LaSilla at an altitude of 2400 metres

     
  • richardmitnick 2:38 pm on January 19, 2019 Permalink | Reply
    Tags: , , , , Disentangling starlight, ESOblog   

    From ESOblog: “Disentangling starlight” 

    ESO 50 Large

    From ESOblog

    1

    Although they look like fuzzy patches of light, distant galaxies are actually made up of billions of stars and other astronomical intricacies. Telescopes are rarely powerful enough to study the individual stars in galaxies except for those closest to the Milky Way, but a team of scientists has now used the MUSE instrument on ESO’s Very Large Telescope to resolve the stars in the spiral galaxy NGC 300.

    ESO MUSE on the VLT on Yepun (UT4)

    By telling the story of how astronomy has reached this point, team member Martin M. Roth from the Leibniz Institute for Astrophysics Potsdam helps us understand why this result is so exciting.

    Four hundred years ago, Galileo Galilei became the first person to point a telescope at the sky and prove that the hazy band of the Milky Way is actually composed of billions of individual stars. Astronomy has come a long way since then, and nowadays astronomers do not merely look at the stars, but also analyse their chemical composition, measure their rotation and velocity in space, and determine many other physical parameters to find out more about the Universe — all using a technique called spectroscopy, which is the study of the interaction of matter and light.

    Stellar spectroscopy really started taking speed with the emergence of a technique called integral field spectroscopy, around the same time that I joined Leibniz Institute for Astrophysics Potsdam (AIP) as a young astronomer in the early 1990s. This technique allows astronomers to obtain a 3D view of a galaxy in just one shot. It uses an Integral Field Unit (IFU) to divide the field of view into many segments — or pixels — to obtain a more comprehensive overview of the whole. The signal from each pixel is fed into a spectrograph which generates a light spectrum for each one. The pixels in this case are rather lovingly named “spaxels”.

    Even all those years ago it occurred to me that such a device could be used to disentangle the stars in crowded fields, such as in star clusters and distant galaxies, where the light from stars blends together to become a blurry blob. So by 1996, our team at Potsdam had begun to develop our own integral field spectrograph. We called it PMAS — the Potsdam Multi-Aperture Spectrophotometer.

    1
    How integral field spectroscopy works. Credit: ESO

    Several research groups were developing integral field spectrographs at the same time, but the main drawback to all of them was the number of spaxels. PMAS, for example, hosted a mere 256 of them — compare this to your phone camera, which probably has something like 10–15 million pixels. This all changed dramatically with the arrival of MUSE, the Multi Unit Spectroscopic Explorer, on ESO’s Very Large Telescope (VLT). MUSE hosts an incredible 90 000 spaxels and boasts superb sensitivity.

    The primary raison d’etre of MUSE is to study the origin and development of the Universe as a whole, but when ESO invited proposals for MUSE pilot studies almost five years ago, I applied to use the new instrument to try to resolve stars in the nearby spiral galaxy NGC 300. This had already been done for very nearby galaxies in what is called the Local Group but never for galaxies further afield.

    Thankfully, my proposal to observe NGC 300 was chosen as one of the MUSE pilot studies, and we were given observing time! At a distance of six million light-years from the Milky Way, NGC 300 is just outside the Local Group and is what I would describe as a very “typical” spiral galaxy; finding out more about it should help us find out more about how spiral galaxies work in general.

    2
    The intricate network of pipes surrounding the 24 spectrographs of the MUSE instrument on the VLT. The instruments complexity is equaled by its power and productivity. Credit: A. Tudorica/ESO

    But it wasn’t enough just to observe the galaxy using MUSE, it was also necessary to develop some software that could help us visually separate the stars in the MUSE data. A talented doctoral student within our research group created a novel tool to do this. To test the tool, we used our old PMAS spectrograph on a telescope at the Calar Alto Observatory in Spain to measure the speed of some stars in Milky Way star clusters. The tool worked perfectly!

    Calar Alto Observatory located in Almería province in Spain on Calar Alto, a 2,168-meter-high (7,113 ft) mountain in Sierra de Los Filabres

    We then tried out the tool with MUSE images of a cluster of Milky Way stars before the real test — would it work on NGC 300, a galaxy 800 times further away than this star cluster?

    The results turned out to be better than we could have ever imagined! We could see individual stars with incredible clarity and gaseous regions, such as supernova remnants, planetary nebulae, and ionised hydrogen regions were revealed. Amazingly, we could even see dim background galaxies through NGC 300! MUSE is special because it can look at light with a wide range of wavelengths, making many different objects and colours visible.

    4
    This picture of the spectacular southern spiral galaxy NGC 300 was taken using the Wide Field Imager (WFI) at ESO’s La Silla Observatory in Chile.

    ESO WFI LaSilla 2.2-m MPG/ESO telescope at La Silla, 600 km north of Santiago de Chile at an altitude of 2400 metres

    It was assembled from many individual images through a large set of different filters over many observing nights, spanning several years. The main purpose of this extensive observational campaign was to get an unusually thorough census of the stars in the galaxy, counting both the number and varieties of stars and marking regions, or even individual stars, that warrant deeper and more focussed investigation. But such a rich data collection will also have many other uses for years to come.

    The images were mostly taken through filters that transmit red, green or blue light. These were supplemented by images through special filters that allow through only the light from ionised hydrogen or oxygen gas and highlight the glowing clouds in the galaxy’s spiral arms. The total exposure time amounted to around 50 hours.

    Credit: ESO

    5
    The new MUSE images of NGC 300 laid over the WFI image, with individual stars clearly visible. Credit: ESO

    After so many years of preparation, involving the hard work of so many individuals, it’s fair to say that we were overwhelmed when we received the NGC 300 data. But we have merely scratched the surface of a gold mine. We have so much more data to analyse that we have gathered a team of enthusiastic astronomers to go through it, all keen to discover what lies beyond what we once thought was impossible. And through it all, I keep reminding myself that this was a pilot study.

    Not only do we hope to use MUSE to look at even more galaxies, ESO is currently building an instrument called 4MOST that will be dedicated to disentangling starlight and imaging up to 2400 individual stars per single exposure in the Milky Way. The goal is to study millions of stars in the attempt to unravel our galaxy’s formation history and evolution, as part of a vibrant field of research called “galactic archaeology”.

    But MUSE is already enabling “extragalactic archaeology” for the first time ever. With its ability to collect huge amounts of light and create incredibly sharp images, ESO’s Extremely Large Telescope will be able to take extragalactic archaeology even further, investigating individual stars in other galaxies to help us find out more about the Universe.

    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 EEuropean 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,

    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.

    ALMA Array
    ALMA on the 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 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)

    ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

    ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

    ESO ExTrA telescopes at Cerro LaSilla at an altitude of 2400 metres

     
  • richardmitnick 3:59 pm on December 21, 2018 Permalink | Reply
    Tags: , , , , , , ESOblog, Mirrors   

    From ESOblog: “From giant telescopes to mini particle accelerators” 

    ESO 50 Large

    From ESOblog

    1
    How ESO helped CERN’s AWAKE experiment catch a wave

    How can knowledge about building ESO’s world-class telescopes help accelerate tiny particles at CERN? Surprisingly, it can be vital! Organisations that are part of the EIROforum often share resources and knowledge, and two ESO engineers were recently involved in designing CERN’s newest particle acceleration experiment, contributing expertise that was essential in the successful start of the experiment earlier this year. In this week’s blog post those two scientists, Marco Quattri and Paolo La Penna, describe their role in the project.

    2
    Paolo La Penna

    3
    Marco Quattri

    The Advanced Wakefield (AWAKE) experiment investigates how charged particles can be accelerated using strong electric fields called plasma wakefields. A wakefield is an electromagnetic field that oscillates in a plasma. Charged particles “surf” the positive and negative zones of the wave, becoming accelerated to very high velocities meaning they have a lot of energy. Plasma wakefields can achieve energies hundreds of times greater than fields in traditional accelerators, making them a promising technique to use in future particle physics research.

    3
    Particles being accelerated in a plasma wakefield. Credit: CERN-AWAKE group.

    While previous wakefield accelerators used either intense laser pulses or electrons to create an electric field, AWAKE is the first experiment to instead use high-intensity protons beams sent through plasma cells to generate these fields. Using protons to create a wakefield means that particles — in this case, electrons — can be accelerated to high velocities in just one step, whereas typically several stages are required to reach such high energies. The acceleration obtained over a given distance in a plasma wakefield is also much higher than in existing technologies; slow-moving electrons enter AWAKE and are accelerated by a factor larger than a hundred over a distance of just ten metres. CERN’s Large Hadron Collider, in comparison, was designed to be almost 27 kilometres long to enable sufficient acceleration.

    Once electrons have been accelerated in the wakefield, a magnet deflects them, directing them to a screen that emits light when hit by high-energy electrons. Mirrors reflect the light emitted by the screen towards a camera, in what we call an optical line. This is where we came in, because CERN has no specific expertise in mounting and qualifying large mirrors. The camera is located in an adjacent tunnel to protect it from the large amount of radiation coming from the screen, so the entire line is about 16 metres long and includes three folding mirrors to direct the light. We used a simulation to help calculate the best size and dimensions of these mirrors, based on the properties of the camera lens and the screen dimensions. The simulation also helped specify the surface quality of the mirrors. Optimising the dimensions and surface helps balance quality against cost!

    Having defined the properties of the mirrors, we also assisted with designing their mounts. It is very important that the mounts don’t deform the mirrors at all, as this would blur the resulting image, so we designed them to support the mirrors at three points. We also had to ensure that the mounts protect the mirrors from vibrations propagating through the floor.

    ESO has a long and unique history of designing, mounting and testing large mirrors. Those on our telescopes, for example, must be optimised and supported to direct light in the most effective way possible. The instruments installed on the telescopes also host some complicated optics. So we were able to use the expertise and experience we’ve gained here at ESO and apply it to this new experiment.

    3
    The mirrors that Paolo and Marco helped design. Credit: CERN-AWAKE group.

    Overall, we provided CERN with support in computing the optical and mechanical performances of the mirrors, designing the mounts, defining the mirror specifications, alignment and calibration procedures and procuring the whole line. Although the installation of AWAKE began in 2011, ESO only started collaborating on the project in mid-2016. In May 2018 the team successfully demonstrated the acceleration of electrons and their detection on the screen. This marked the first-ever demonstration of accelerating electrons using a wakefield in a plasma.

    It was really great to support CERN, an ESO partner institution, in this way. It was particularly interesting to see how our expertise in designing telescopes to observe objects in the distant Universe can also be helpful for much smaller-scale, Earth-based projects. We would like to thank our line managers for supporting us in carrying out this project and would encourage other ESO employees to take opportunities to work with other partner institutions.

    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 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.

    ALMA Array
    ALMA on the 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 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)

    ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

    ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

    ESO ExTrA telescopes at Cerro LaSilla at an altitude of 2400 metres

     
  • richardmitnick 4:08 pm on December 14, 2018 Permalink | Reply
    Tags: , , , , ESOblog, Monitoring the changing R Aquarii   

    From ESOblog: “Monitoring the changing R Aquarii” 

    ESO 50 Large

    From ESOblog

    1

    Three generations of astronomy in the last installment of ESO’s R Aquarii week

    R Aquarii is a binary system in which the violent interaction between two stars is creating a swirling nebula and a dazzling jet of light. A team of scientists have spent three decades studying this famous and unique object with ESO telescopes to find out more about various astronomical phenomena. So far this week we have published a Picture of the Week and a Photo Release looking at different aspects of this interesting star-nebula system. We wrap up the week with a blog post from Romano Corradi, an R Aquarii expert, who tells us first-hand about why this star is so interesting to study, and how our observation methods have changed over the last thirty years.

    I am particularly interested in R Aquarii because it is a symbiotic star — two interacting stars locked in a binary system in which a hot white dwarf strips away matter from a nearby cool giant star. In the case of R Aquarii, the giant is a highly evolved pulsating star reaching the end of its life; it will soon completely shed its external gaseous envelope to become a white dwarf just like its partner.

    The mass pulled away from this giant star creates an extended complex nebula that is further shaped by the surplus material that the white dwarf occasionally ejects to create loops and arcs. An accretion disk around the white dwarf sends out a jet of hot X-ray emitting material. This is the source of the S-shaped feature visible in the main photo above, which we took using ESO’s Very Large Telescope in 2012. At a distance of 650 light-years, R Aquarii is one of the closest known symbiotic systems and offers a unique opportunity to find out more about these special stars.

    One of the most challenging aspects of astronomy is that things change extremely slowly, so it can be difficult to study the dynamical nature of systems like R Aquarii, for example how fast they expand. We can only see how systems evolve by regularly taking images of them.

    My PhD supervisor, Hugo Schwarz, began imaging and studying R Aquarii in the mid-1980s, and I joined him as a PhD student in 1991. Over the years I have continued to study the symbiotic star system, and now work on the research with my own PhD students. By combining 30 years of observations, and three generations of scientific ideas and expertise, we now have a good idea of how the system evolves. But two of the key ingredients of this project really have been patience and perseverance.

    2
    R Aquarii observed using the New Technology Telescope [see NTT below] in 1991. The white vertical line in the middle is caused by light from the red giant and bright inner nebula saturating the detector. Credit: Romano Corradi

    Our work has changed a lot during this time. When I joined 27 years ago, image processing was extremely slow and direct human interaction was needed at every stage in making observations. No real pre-existing codes for processing raw data were available for most astronomical instruments, just basic guides or “recipes”. In addition to this, in the early nineties we typically had to be physically present at a telescope to observe, but nowadays we are often able to use telescopes remotely — almost from the comfort of our own homes! Improved computing power has of course made a huge difference to us. I was lucky to appear on the “astronomy scene” when large and highly efficient CCDs became commonly available in astronomical observatories. This all combined to make our research much more efficient.

    When I arrived at ESO’s La Silla Observatory as a student, I had the chance to take advantage of the superb image quality of the recently installed New Technology Telescope (NTT). The NTT really was a step forward in measuring the fine details necessary to follow the apparent growth of nearby nebulae. Since then, we have used several telescopes for our work, mainly at ESO and at the Observatorio del Roque de los Muchachos on La Palma.

    Roque de los Muchachos Observatory is an astronomical observatory located in the municipality of Garafía on the island of La Palma in the Canary Islands, at an altitude of 2,396 m (7,86

    Because R Aquarii is large and fairly close, it is relatively easy to observe the region around the central binary system out to the place where the outflow mixes with the interstellar medium. At such scales, we see the imprint of the initial “kick” of the outflow. But in order to study the central “engine”, higher spatial resolutions were needed, such as those provided by the SPHERE instrument on the VLT.

    ESO SPHERE extreme adaptive optics system and coronagraphic facility on the extreme adaptive optics system and coronagraphic facility on the VLT UT3, Cerro Paranal, Chile, with an elevation of 2,635 metres (8,645 ft) above sea level

    Now a team of scientists led by Hans Martin Schmid from ETH Zurich University has actually used SPHERE to image the innermost regions of R Aquarii in extraordinary detail — even better than can be done from space — enabling them to resolve the source of the jet to further investigate how it is launched into space. It also marks the first time that we can resolve the red giant and white dwarf in this binary system.

    3
    New VLT/SPHERE observations of R Aquarii shows the binary star itself, as well as the jets of material spewing from the stellar couple. The fantastically-detailed images allow the giant star and the white dwarf star in R Aquarii to be resolved.
    Credit: ESO/Schmid et al./NASA/ESA

    R Aquarii is not the only “large-scale structure” this research could help us understand, in fact the information could revolutionise our understanding of the formation and evolution of astrophysical jets. Using SPHERE to image R Aquarii was really a test to see how much the instrument’s new ZIMPOL camera could help with investigating all of these systems in more detail than ever before. The team found that the SPHERE images were of an incredible quality, as well as being complementary to Hubble observations.

    ESO SPHERE ZIMPOL camera schematic

    The timelapse below shows just how much R Aquarii has changed over the last 20 years. At the beginning of the video, we see an image from the Nordic Optical Telescope (NOT) taken in 1997.


    The evolution of the chaotic and fascinating binary star system R Aquarii, from 1997 to today.
    Credit: T. Liimets et al./ESO/M. Kornmesser


    Nordic Optical telescope, at Roque de los Muchachos Observatory, La Palma in the Canary Islands, Spain, Altitude 2,396 m (7,861 ft)

    This is combined with another NOT image from 2007 and a VLT image from 2012 to show how the nebula is growing over time. We can even see how different parts of the system expand with different speeds, for example the white jet grows particularly fast. It is so rare to be able to see theis kind of evolution in astronomy, and I think it’s amazing!

    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-

    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 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.

    ALMA Array
    ALMA on the 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 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)

    ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

    ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

    ESO ExTrA telescopes at Cerro LaSilla at an altitude of 2400 metres

     
  • richardmitnick 4:08 pm on November 30, 2018 Permalink | Reply
    Tags: , , , , , ESOblog   

    From ESOblog: “Revealing the True Nature of Asteroids” 

    ESO 50 Large

    From ESOblog

    A team of scientists are currently using ESO’s Very Large Telescope to survey the largest asteroids in the Solar System. Nicknamed HARISSA, the survey has recently gathered lots of information on asteroid Psyche, special because of its metallic nature. In this week’s blog post the team behind the project explain what Psyche can tell us about the history of the Solar System, and how their research will feed into a NASA mission to study the same asteroid.

    Q. Firstly, could you tell us a bit about the HARISSA survey.

    Pierre (P): We are finding out more about some of the largest asteroids in the Asteroid Belt using the SPHERE instrument on the Very Large Telescope (VLT).

    ESO SPHERE extreme adaptive optics system and coronagraphic facility on the extreme adaptive optics system and coronagraphic facility on the VLT MELIPAL UT3, Cerro Paranal, Chile, with an elevation of 2,635 metres (8,645 ft) above sea level

    With the VLT, we can see surface features such as craters, allowing us to carry out geology and geophysics from here on Earth for the first time ever. Craters tell us more about the age and collisional history of each asteroid, as a higher number of craters imply an older surface or more violent past. They can also hint at an asteroid’s internal structure.

    Franck (F): We have been observing asteroids for years using the W.M. Keck Observatory, so when we found out about the VLT’s next-generation adaptive optics system, we couldn’t wait to use it to image asteroids with a much better resolution — four times sharper than that of the Hubble Space Telescope! The survey is still ongoing, and more data is coming, so we hope that there will be some interesting results in the future.

    Q. So you observed Psyche as part of this HARISSA survey — could you give us a brief overview of how you observed this asteroid and what you found out?

    P: We combined our VLT observations from May this year with additional data from the last 20 years, many of which came from amateur astronomers! In total, we had 206 data sets for Psyche, and we fed them all into an algorithm to find out about its size and shape. We discovered that it is 226 kilometres wide, with two particularly interesting features — one very bright patch and one huge crater almost half the size of the asteroid itself.

    F: We named the bright patch Panthia and the crater Meroe after the twin witches in the story Metamorphosis, which Psyche’s name also comes from. We also looked for a moon, because measuring a moon’s orbit could give us a good estimate of Psyche’s mass. But we are now almost certain that Psyche hosts no moons larger than one kilometre in diameter.

    2
    Images of Psyche from the HARISSA survey, with Meroe and Panthia highlighted. Credit: ESO/LAM

    Q. Could you tell us a bit about asteroids? What are they and why should we study them?

    F: Asteroids are the remnants of the formation of the Solar System. In a way, they are the “bricks” that make up the Solar System, and it’s important to understand the bricks to understand the whole structure.

    P: Most asteroids live in the Asteroid Belt between Mars and Jupiter. But we believe that they actually formed in a wider range of locations. Some are very rocky, and probably formed closer to the Sun, and some are more icy, having probably formed further out, between Jupiter and Neptune. There are clear differences between these icy and rocky bodies — rocky asteroids are covered in craters, but the presence of ice smooths these scars on the icy asteroids. Rarer, metal-rich asteroids also exist.

    Q. Why did you decide to investigate this particular asteroid? Why is it interesting?

    P: Psyche is much richer in metals than other asteroids, which implies that it formed a very long time ago. Being part of the first generation of planetary building blocks means that it could be useful for understanding the early Solar System.

    F: Also, past radar observations implied that this asteroid is a metallic world with a metal-rich surface. These types of asteroids are rare compared to rocky and icy asteroids. We are trying to observe all types of asteroids through the HARISSA programme, and Psyche is one of the few large metallic asteroids believed to exist.

    F: But actually, we were surprised that our observations showed Psyche to be a mesosiderite asteroid, meaning it is a mixture of metal and rock. Mesosiderite meteorites make up just 0.7% of the meteorites found on Earth, making them even rarer than purely metallic meteorites. This leads us to wonder which asteroids they came from and where these parent bodies were formed. And now we consider that Psyche could be the source of these meteorites!

    P: It is possible that mesosiderite asteroids are the result of a collision between small molten objects and a large asteroid early in the history of the Solar System, or maybe they arose from the breakup and reassembly of a large asteroid. Understanding the formation of Psyche with a dedicated NASA mission will hopefully shed some light on this mystery to tell us more about the early Solar System. That’s really exciting!

    Q. So why is NASA sending a spacecraft to Psyche?

    P: Metal-rich asteroids have not been observed in much detail before. And although we have found out a lot from ground-based observations, some measurements can only be done in situ, for example analysing the composition of the rock to find out what elements are on the surface and measuring the magnetic field around Psyche. The NASA spacecraft will carry instruments that can do these things. It will also measure Psyche’s gravity to find out about its interior, possibly helping us determine whether the asteroid formed as a result of a collision.

    F: Metal-rich asteroids are like a missing piece in the puzzle of our understanding of the formation of the Solar System. And one topic that comes up quite a lot at the moment is asteroid mining. These metal-rich objects are the type that we would mine for precious metals that are becoming more difficult to collect on Earth. But first, we need to answer questions like: how much metal is in the rock? how could we go about extracting it? Moral questions surround asteroid mining, but at least if we understand the science, we can get a broader view of the situation.

    NASA Psyche spacecraft

    Q. Will your observations be useful for the NASA mission?

    F: By carrying out the first exploration of the asteroid, we observed some things that will be very useful for the Psyche mission team, for example, we now know that there is no large moon for the spacecraft to potentially collide with. We also found that the features on the surface vary by about 10% in brightness; this knowledge will help the Psyche team tune their instruments to clearly see surface features — just like when your camera has to adjust to different light levels here on Earth.

    NASA will use all this information to optimise their mission. For example, they might plan to start by studying the most interesting geophysical areas — Meroe or Panthea, perhaps — as they don’t know exactly how long the spacecraft will survive in deep space. They want to get the most interesting results right at the beginning!

    Q. What do you hope to do in the future?

    P: Psyche is moving closer to Earth, so in a few months it will be even larger than when we first observed it. If the HARISSA programme is extended, we hope to get additional observations; new images would allow us to see other sides of the asteroid that weren’t visible when we first observed it in May, meaning we could identify and map new features.

    F: We would also like to use the Extremely Large Telescope (ELT) [below] to image this asteroid. The resolution will initially be two to three times better than that of the VLT, so we would be able to see small details on the surface, and to spot if there is a tiny moon. We already have images of the surfaces of the very largest asteroid belt objects, but the ELT will allow us to clearly spot craters on the surfaces of more than 100 asteroids!

    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 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.

    ALMA Array
    ALMA on the 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 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)

    ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

    ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

    ESO ExTrA telescopes at Cerro LaSilla at an altitude of 2400 metres

     
  • richardmitnick 10:55 am on November 25, 2018 Permalink | Reply
    Tags: , , , , ESOblog, Missing Solar Siblings   

    From ESOblog: “Missing Solar Siblings” 

    ESO 50 Large

    From ESOblog

    1

    23 November 2018

    Could the Sun’s long-lost relatives help us find life elsewhere in the Universe?

    It is believed that the Sun has a few thousand solar siblings, any of which could host living organisms similar to those found on Earth. A team of scientists recently searched through data from several ESO telescopes as well as ESA’s Gaia mission to find one such sibling.

    ESA/GAIA satellite

    Vardan Adibekyan, who led the research, tells us more about what we can learn from these special stars, including why they are a good place to search for life.

    Q. First of all, what is a solar sibling and why should we study them?

    A. It is generally accepted that most stars are born when clouds of dust and gas condense to form stellar clusters. We believe that the Sun was formed in one such cluster about 4.5 billion years ago, together with a few thousand other stars known as “solar siblings”. As time went by, the Sun’s birth cluster disbanded, with its members spreading throughout the Milky Way.

    Different theoretical models suggest that only a handful of these solar sisters are still in the vicinity of the Sun, which makes locating them very difficult. But finding them would help us understand where in the galaxy — and under which conditions — the Sun formed, as well as how we ended up in our current position. There is also a possibility that life was transported between stars in this cluster, potentially making solar siblings an ideal place to search for life that at least started off the same as life on Earth, even if it may have evolved differently.

    Q. Why is it important to understand where and how the Sun formed?

    A. We don’t have much direct information about the Sun’s past. We know that a star’s metallicity — the amount of elements other than hydrogen and helium in its atmosphere — should be similar to the metallicity of the cloud from which it was born. But we have observed that the Sun’s metallicity is actually higher than the average metallicity of most nearby stars of a similar age. This peculiarity is usually explained by the hypothesis that the Sun migrated from the inner part of the Milky Way, where the interstellar medium is more metal-rich.

    At the same time, some of the characteristics of the Solar System suggest that its very early evolution was quite violent, with semi-catastrophic events such as the explosion of a nearby supernova and a close encounter with another star. Finding and characterising solar siblings would help us to better understand the birth and evolution of the Solar System.

    2
    This open cluster is IC 4651, a stellar grouping that lies at in the constellation of Ara (The Altar). The Sun was born in a similar open cluster. Credit: ESO

    Q. There have been searches for solar siblings in the past. What makes your research different?

    A. A good solar sibling candidate has two characteristics: as it would have formed at the same time as the Sun, it should have the same age, and as it would have formed from the same cloud, it should also have the same chemical make-up.

    Indeed, several previous attempts have been made to find solar siblings, and in most of these studies, scientists started by searching for stars moving in a way that some models of the galaxy suggest that solar siblings should move. Then they verified whether the chemical composition and age of the candidate siblings were similar to those of the Sun. But the results are limited because of the dependence on the models used.

    In 2014, I took a different approach to searching for solar siblings, in collaboration with others including Sérgio Batista, a Master’s student at Instituto de Astrofísica e Ciências do Espaço (IA) in Portugal, which is the institute I also work for. For that research, we selected a sample of 1111 stars in the solar vicinity, all previously observed with the HARPS spectrograph on the ESO 3.6-metre telescope [see below].

    We preselected stars with chemical compositions that best match the Sun’s composition, then we estimated their ages and finally, we studied their motions. But the sample of stars was too small, and the number of chemical elements we could study was limited, so we had to try something else.

    3
    A spectrometer splits up light from a star into a spectrum, which can tell us about its chemical composition. Credit: ESO

    Q. So what did you do next?

    A. I decided to undertake a much larger search with the help of Patrick de Laverny and Alejandra Recio-Blanco from the Côte d’Azur Observatory in France.

    Côte d’Azur Observatory, Nice, France Lunar Laser Ranging


    Côte d’Azur Observatory, Nice France

    They were working on a project called AMBRE to create a very large database of light spectra from local stars. A spectrum can tell us a huge amount about a star’s chemical composition.

    The AMBRE database contains lots of archival data from many different instruments, including ESO’s FEROS, HARPS, UVES and GIRAFFE. In total, the database consists of about 230 000 spectra, corresponding to 17 000 stars, all of which have been carefully analysed. From the database, we selected 55 stars with a metallicity similar to that of the Sun for further investigation, and we found that 12 of these are actually chemically identical to the Sun. We combined this information with data about the positions and motions of these stars from ESA’s Gaia mission which enabled us to calculate precise ages for the most interesting stars.

    We found one really good candidate for a solar sibling: HD186302. Like the Sun, this is a G-type main sequence star, identical to the Sun in age and composition. Its other physical properties are also very similar to the Sun’s, making it not just a solar sibling, but also a solar twin.

    Q. Why is it particularly exciting that HD186302 is also a solar twin?

    A. The term “solar sibling” is often confused with “solar twin”. Solar twins are stars that have similar physical properties — such as temperature, metallicity and surface gravity — to the Sun, but they didn’t necessarily form in the same cluster. Solar siblings, on the other hand, always form in the same cluster but apart from their metallicity, don’t necessarily match the Sun’s physical characteristics. As the saying goes, we got “two birds with one stone”.

    The search and study of solar twins is an important subject in itself, because the comparison of properties of such stars with those of our Sun helps to understand how typical or unique the Sun is. And perhaps it’s reasonable to say that a star with similar characteristics to the Sun would be more likely to support life than one with very different characteristics — who knows!

    Q. Tell us more about why solar siblings are good candidates to search for life elsewhere in the Universe.

    A. The somewhat speculative hypothesis that biological materials that can spark life can travel through space and settle in new habitats is called panspermia. In particular, the transfer of life between exoplanet systems is called interstellar lithopanspermia. Thus, solar siblings can be good candidates to search for life, since it is possible that life was transported between planets around stars in the Sun’s birth cluster.

    There was a violent period in the history of the Solar System called the Late Heavy Bombardment, during which many asteroids are thought to have collided with the inner, rocky planets, sending material flying into space. Some calculations show that there is a tiny probability that life spread from Earth to other planets or exoplanet systems during this period. If we are lucky, and our sibling candidate has a planet, and the planet is a rocky one, in the star’s habitable zone, and finally if we are extremely lucky and this planet has been “contaminated” by seeds of life from Earth (or vice versa!)… voilá: we have an Earth 2.0, orbiting a Sun 2.0.

    Q. And will you try to find planets around this star?

    A. Absolutely! Unfortunately, the ESO archive has very few spectra of this star, so at the moment we don’t have enough information to investigate whether there are planets orbiting it. But our team at IA plans to start a campaign to search for possible planets using HARPS and the ESPRESSO instrument on the Very Large Telescope. Not only is there the potential to find life, but finding and characterising planetary systems around solar siblings could return very important information about planet formation in a common environment.

    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 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.

    ALMA Array
    ALMA on the 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 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)

    ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

    ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

    ESO ExTrA telescopes at Cerro LaSilla at an altitude of 2400 metres

     
  • richardmitnick 4:18 pm on November 14, 2018 Permalink | Reply
    Tags: "Searching for an Exoplanet", , , , , , ESOblog,   

    From ESOblog: “Searching for an Exoplanet” 

    ESO 50 Large

    From ESOblog

    1

    14 November 2018

    After archival data indicated the possible presence of a planet around nearby Barnard’s Star, a team of scientists undertook an epic campaign to try to confirm its presence. The result, published this week and described in an ESO press release, was the discovery of evidence for the second-closest exoplanet to Earth. In this blog post, lead scientist Ignasi Ribas helps us investigate the discovery further and look at the incredible story behind it.

    Related ESO press release can be found here.
    See https://sciencesprings.wordpress.com/2018/11/14/from-european-southern-observatory-super-earth-orbiting-barnards-star/ for a full accounting of the instrumentation used in this project and also the science team.

    Q. Could you start by telling us what you found and why it’s exciting?

    A. We have combined 20 years of observations to discover a candidate planet around Barnard’s Star, one of the nearest stars to the Sun. Barnard’s Star has been famous for a long time, not only because of its proximity and because it is the fastest moving star in the night sky, but also because back in the 1960s scientists thought that they found an exoplanet system orbiting it. Those planets were later disproved, but now we believe that we really have found one!

    We are 99% sure that this planet exists. It is a cold super-Earth at least 3.2 times the mass of the Earth, orbiting 60% closer to its parent star than Earth does to the Sun. Even so, Barnard’s Star is so small and cool that it provides this planet with just 2% of the energy that the Earth receives from the Sun, and therefore this planet is a very cold world.

    2
    Data from many different instruments, including ESO´s planet-hunter HARPS, have revealed this frozen, dimly lit world. (Artist´s impression)
    Credit: ESO/M. Kornmesser

    Q. Why do you think it’s important to search for planets around other stars?

    A. Personally I am involved in this area of research because I want to understand our place in the Universe. I think part of understanding our situation is to find out about nearby planets, to discover their properties and figure out how they formed. This will help us discover whether Earth is unique or whether life could be commonplace in the Universe.

    Much of the Universe is still a complete mystery; at the moment we are exploring it long-distance, from Earth, but perhaps someday in the distant future we will really be able to visit these planets, so we need to find out more about them first.

    Q. So tell us how you went about finding this planet.

    A. We used a technique called the radial velocity, or Doppler, method.

    Radial Velocity Method-Las Cumbres Observatory

    Radial velocity Image via SuperWasp http:// http://www.superwasp.org/exoplanets.htm

    When a planet orbits a star, its gravity pulls the star forwards and backwards just a tiny amount, changing its velocity slightly and making the star wobble. When a star comes towards us, its light becomes “squashed” and the wavelength we see is more blue, and when the star moves away, its light reddens, in what is known as the Doppler effect. This method allows us to find out the minimum mass of the planet, but we must use complementary techniques to determine a planet’s true mass.

    We went through huge amounts of data dating back to the 90s to look for a pattern in this star’s motions and saw that it was moving forwards and backwards with a regular rhythm. The wavelength, and therefore the star’s velocity, varies with a period of roughly 233 days, implying that a planet orbits once every 233 days. Determining how much the wavelength changes over this time allowed us to figure out how fast the star moves towards and away from us. The mass of the planet is related to the change in velocity, so we were able to calculate the minimum mass of the planet to be about three times the mass of Earth.


    This animation shows how astronomers watch for changes in the wavelength of light from a star to search for exoplanets.
    Credit: ESO/L. Calçada

    Q. Planets have been discovered around stars thousands of light-years away. Barnard’s Star is just six light-years away, so why was this planet not found before?

    A. There have actually been many previous searches for planets around Barnard’s Star, and even announcements of discoveries, but not one has ever been confirmed. The thing is that the candidate planet we found is so small and so far from its host star that its effect on the star is really, really tiny. The planet only changed the star’s speed by 4.3 km/h in each direction and with a long period of 233 days, making it extremely difficult to detect. Finding the planet was only possible by collecting an enormous number of velocity measurements. In total, we combined nearly 800 measurements from seven different facilities.

    In particular, between 2016 and 2017 we used the High Accuracy Radial velocity Planet Searcher (HARPS) on the ESO 3.6-metre telescope to observe Barnard’s Star on every possible night that we could, to gather as much information as possible on how its velocity changes over time. It is thanks to HARPS and the CARMENES instrument at Calar Alto Observatory that we can be sufficiently confident that this planet exists.

    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.

    CARMENES spectrograph, mounted on the Calar Alto 3.5 meter Telescope, located in Almería province in Spain on Calar Alto, a 2,168-meter-high (7,113 ft) mountain in Sierra de Los Filabres



    Calar Alto 3.5 meter Telescope, located in Almería province in Spain on Calar Alto, a 2,168-meter-high (7,113 ft) mountain in Sierra de Los Filabres

    Q. You say that you are 99% sure that this is a planet. Where does the uncertainty come from? And how certain do you have to be before you are convinced this is a planet?

    A. We would like to be 99.9% certain that this is a planet before we stop observing it. We already feel very sure — it passes all the tests that a planet should pass, but we will continue to make more observations to become more certain.

    The uncertainty comes from the intrinsic error in each radial velocity measurement. In this case, the typical uncertainty of our data is 3.6 km/h, meaning that each velocity measurement we obtain could actually be anywhere within an interval of 3.6 km/h around the value we observe. This is large compared to the velocity values of 4.3 km/h that we are dealing with, so we needed hundreds of measurements to beat down the errors. Furthermore, such precision requires instruments to be extremely stable over timescales of decades so that we can trust that all radial velocities are free from systematic effects. Heat and cold, for example, can affect how instruments operate, so engineers try to keep the instruments at a constant temperature and we are sure to correct for any change. We are convinced that instrument effects cannot be responsible for the 4.3 km/h signal we observed because we see the same value in datasets from different instruments.

    Q. If it isn’t a planet, what else could it be?

    A. There is a small chance that the signal is produced naturally by the star. We found that Barnard’s Star spins very slowly, with a rotation period of about 140 days. As the star rotates, the starspots on its surface rotate with it, appearing and disappearing in a way that could give rise to a signal similar to the one we observed. We calculated the possibility of this to be 0.8% — small, but not zero. More observations will help us decrease this small chance even further and nail the case for the planetary nature of the radial velocity modulations that we are seeing.

    Q. Will you try to confirm that this is a planet in the future? How will you do this?

    A. Absolutely! It’s proximity makes this planet a prime target for exoplanet research. For now, we will continue to collect more radial velocity data to push down the uncertainty even further. Then we would like to observe the planet using different techniques, for example, we could use the Hubble Space Telescope or ESA’s Gaia mission to look for the change in the position of the star in the sky as the planet’s gravity pulls the star around as it orbits. Using a space telescope to do this would tell us more about the properties of this planet.

    NASA/ESA Hubble Telescope

    ESA/GAIA satellite

    This planet is one billion times fainter than its parent star, so it would be extremely difficult to take a direct image of it — we could not dream of doing this with the telescopes that exist today. But now we know where to look for it, we would like to use the amazing imaging capabilities of ESO’s future Extremely Large Telescope to image it.

    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).

    This would reveal a huge amount of information about the planet, for example about its orbit, radius, mass and temperature.

    Q. Earlier you mentioned that scientists thought they found a planet around Barnard’s Star back in the 1960s. Did you see any sign of this “planet” whilst you were carrying out this research?

    A. We did find something! Our analysis revealed that the velocity of Barnard’s Star varies not only with the 233-day period of the planet discovered by us, but also with an intriguing long-term period of 15–20 years. This period is similar to that of the planets proposed in the 1960s but the radial velocity variations are much smaller than would be expected. If the variations were caused by a second planet, it would be very distant from its parent star and with a mass similar to Neptune.

    But we actually think it’s more likely that the long-term variation is caused by changes in the magnetic activity of the star. Just like the Sun — which has a sunspot cycle of about 11 years — Barnard’s Star gets more and less active over time. Very precise position measurements using the Hubble Space Telescope or Gaia could be used to further investigate the possibility of an outer planet orbiting Barnard’s star.

    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 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.

    ALMA Array
    ALMA on the 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 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)

    ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

    ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

    ESO ExTrA telescopes at Cerro LaSilla at an altitude of 2400 metres

     
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