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  • richardmitnick 2:12 pm on June 4, 2018 Permalink | Reply
    Tags: "Too Many Massive Stars in Starburst Galaxies, , , , , , ESO Paranal VLT, , Near and Far"   

    From ALMA and VLT: “Too Many Massive Stars in Starburst Galaxies, Near and Far” 

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

    From ALMA

    and

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    From European Southern Observatory

    4 June 2018

    Nicolás Lira
    Education and Public Outreach Coordinator
    Joint ALMA Observatory, Santiago – Chile
    Phone: +56 2 2467 6519
    Cell phone: +56 9 9445 7726
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    Zhi-Yu Zhang
    University of Edinburgh and ESO
    Garching bei München, Germany
    Tel: +49-89-3200-6910
    Email: zzhang@eso.org

    Fabian Schneider
    Department of Physics — University of Oxford
    Oxford, United Kingdom
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    Email: fabian.schneider@physics.ox.ac.uk

    Rob Ivison
    ESO
    Garching bei München, Germany
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    Email: rob.ivison@eso.org

    Mariya Lyubenova
    ESO Outreach Astronomer
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    Education and Public Outreach Officer, NAOJ Chile
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    Public Information Officer
    National Radio Astronomy Observatory Charlottesville, Virginia – USA
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    1
    This artist’s impression shows a dusty galaxy in the distant Universe that is forming stars at a rate much higher than in our Milky Way. New ALMA observations have allowed scientists to lift the veil of dust and see what was previously inaccessible — that such starburst galaxies have an excess of massive stars as compared to more peaceful galaxies.
    Credit: ESO/M. Kornmesser

    2
    This image shows the four distant starburst galaxies observed by ALMA. The top images depict the 13CO emission from each galaxy, while the bottom ones show their C18O emission. The ratio of these two isotopologues allowed astronomers to determine that these starburst galaxies have an excess of massive stars. Credit: ALMA (ESO/NAOJ/NRAO), Zhang et al.


    Astronomers using ALMA and the VLT have discovered that starburst galaxies in both the early and the nearby Universe contain a much higher proportion of massive stars than is found in more peaceful galaxies. The video is available in 4K UHD. Credit: ESO.
    Directed by: Nico Bartmann.
    Editing: Nico Bartmann.
    Web and technical support: Mathias André and Raquel Yumi Shida.
    Written by: Stephen Molyneux and Richard Hook.
    Music: written and performed by Stan Dart (www.stan-dart.com).
    Footage and photos: ESO, M. Kornmesser, L. Calçada.
    Executive producer: Lars Lindberg Christensen.

    Astronomers using ALMA and the VLT have discovered that both starburst galaxies in the early Universe and a star-forming region in a nearby galaxy contain a much higher proportion of massive stars than is found in more peaceful galaxies. These findings challenge current ideas about how galaxies evolved, changing our understanding of cosmic star-formation history and the build up of chemical elements.

    Probing the distant Universe a team of scientists, led by University of Edinburgh astronomer Zhi-Yu Zhang, used the Atacama Large Millimeter/submillimeter Array (ALMA) to investigate the proportion of massive stars in four distant gas-rich starburst galaxies [1]. These galaxies are seen when the Universe was much younger than it is now so the infant galaxies are unlikely to have undergone many previous episodes of star formation, which might otherwise have confused the results.

    Zhang and his team developed a new technique — analogous to radiocarbon dating (also known as carbon-14 dating) — to measure the abundances of different types of carbon monoxide in four very distant, dust-shrouded starburst galaxies [2]. They observed the ratio of two types of carbon monoxide containing different isotopes [3].

    “Carbon and oxygen isotopes have different origins”, explains Zhang. “18O is produced more in massive stars, and 13C is produced more in low- to intermediate-mass stars.” Thanks to the new technique the team was able to peer through the dust in these galaxies and assess for the first time the masses of their stars.

    The mass of a star is the most important factor determining how it will evolve. Massive stars shine brilliantly and have short lives and less massive ones, such as the Sun, shine more modestly for billions of years. Knowing the proportions of stars of different masses that are formed in galaxies therefore underpins astronomers’ understanding of the formation and evolution of galaxies throughout the history of the Universe. Consequently, it gives us crucial insights about the chemical elements available to form new stars and planets and, ultimately, the number of seed black holes that may coalesce to form the supermassive black holes that we see in the centres of many galaxies.

    Co-author Donatella Romano from the INAF-Astrophysics and Space Science Observatory in Bologna explains what the team found: “The ratio of 18O to 13C was about 10 times higher in these starburst galaxies in the early Universe than it is in galaxies such as the Milky Way, meaning that there is a much higher proportion of massive stars within these starburst galaxies.”

    The ALMA finding is corroborated by another discovery in the local Universe. A team led by Fabian Schneider of the University of Oxford, UK, made spectroscopic measurements with ESO’s Very Large Telescope of 800 stars in the gigantic star-forming region 30 Doradus in the Large Magellanic Cloud in order to investigate the overall distribution of stellar ages and initial masses [4].

    30 Doradus, The Tarantula Nebula or NGC 2070, resembles the legs of a tarantula 3 December 2009 ESO IDA Danish 1.5 m R. Gendler, C. C. Thöne, C. Féron, and J.-E. Ovaldsen

    Schneider explained, “We found around 30% more stars with masses more than 30 times that of the Sun than expected, and about 70% more than expected above 60 solar masses. Our results challenge the previously predicted 150 solar mass limit for the maximum birth mass of stars and even suggest that stars could have birth masses up to 300 solar masses!”

    Rob Ivison, co-author of the new ALMA paper, concludes: “Our findings lead us to question our understanding of cosmic history. Astronomers building models of the Universe must now go back to the drawing board, with yet more sophistication required.”
    Notes

    [1] Starburst galaxies are galaxies that are undergoing an episode of very intense star formation. The rate at which they form new stars can be 100 times or more the rate in our own galaxy, the Milky Way. Massive stars in these galaxies produce ionising radiation, stellar outflows, and supernova explosions, which significantly influence the dynamical and chemical evolution of the medium around them. Studying the mass distribution of stars in these galaxies can tell us more about their own evolution, and also the evolution of the Universe more generally.

    [2] The radiocarbon dating method is used for determining the age of an object containing organic material. By measuring the amount of 14C, which is a radioactive isotope whose abundance continuously decreases, one can calculate when the animal or plant died. The isotopes used in the ALMA study, 13C and 18O, are stable and their abundances continuously increase during the lifetime of a galaxy, being synthesised by thermal nuclear fusion reactions inside stars.

    [3] These different forms of the molecule are called isotopologues and they differ in the number of neutrons they can have. The carbon monoxide molecules used in this study are an example of such molecular species, because a stable carbon isotope can have either 12 or 13 nucleons in its nucleus, and a stable oxygen isotope can have either 16, 17, or 18 nucleons.

    [4] Schneider et al. made spectroscopic observations of individual stars in 30 Doradus, a star-forming region in the nearby Large Magellanic Cloud, using the Fibre Large Array Multi Element Spectrograph (FLAMES) on the Very Large Telescope (VLT).

    ESO/FLAMES on The VLT. FLAMES is the multi-object, intermediate and high resolution spectrograph of the VLT. Mounted at UT2, FLAMES can access targets over a field of view 25 arcmin in diameter. FLAMES feeds two different spectrograph covering the whole visual spectral range:GIRAFFE and UVES.

    Large Magellanic Cloud. Adrian Pingstone December 2003

    This study was one of the first to be carried out that has been detailed enough to show that the Universe is able to produce star-forming regions with different mass distributions from that in the Milky Way.

    7
    Galaxies in the distant Universe are seen during their youth and therefore have relatively short and uneventful star formation histories. This makes them an ideal laboratory to study the earliest epochs of star formation. But at a price — they are often enshrouded by obscuring dust that hampers the correct interpretation of the observations. Credit: ESO/M. Kornmesser

    8
    This kind of galaxy is typically forming stars at such a high rate that astronomers often refer to them as “starbursts”. They can form up to 1000 times more stars per year, compared to the Milky Way. Thanks to the unique capabilities of ALMA, astronomers have been able to measure the proportion of high-mass stars in such starburst galaxies. Credit: ESO/M. Kornmesser

    More information

    The ALMA results are published in a paper entitled Stellar populations dominated by massive stars in dusty starburst galaxies across cosmic time that will appear in Nature on 4 June 2018. The VLT results are published in a paper entitled An excess of massive stars in the local 30 Doradus starburst, which has been published in Science on 5 January 2018.

    The ALMA team is composed of: Z. Zhang (Institute for Astronomy, University of Edinburgh, Edinburgh, UK; European Southern Observatory, Garching bei München, Germany), D. Romano (INAF, Astrophysics and Space Science Observatory, Bologna, Italy), R. J. Ivison (European Southern Observatory, Garching bei München, Germany; Institute for Astronomy, University of Edinburgh, Edinburgh, UK), P .P. Papadopoulos (Department of Physics, Aristotle University of Thessaloniki, Thessaloniki, Greece; Research Center for Astronomy, Academy of Athens, Athens, Greece;) and F. Matteucci (Trieste University; INAF, Osservatorio Astronomico di Trieste; INFN, Sezione di Trieste, Trieste, Italy)

    The VLT team is composed of: F. R. N. Schneider ( Department of Physics, University of Oxford, UK), H. Sana (Institute of Astrophysics, KU Leuven, Belgium), C. J. Evans ( UK Astronomy Technology Centre, Royal Observatory Edinburgh, Edinburgh, UK), J. M. Bestenlehner (Max-Planck-Institut für Astronomie, Heidelberg, Germany; Department of Physics and Astronomy, University of Sheffield, UK), N. Castro (Department of Astronomy, University of Michigan, USA), L. Fossati (Austrian Academy of Sciences, Space Research Institute, Graz, Austria), G. Gräfener (Argelander-Institut für Astronomie der Universität Bonn, Germany), N. Langer (Argelander-Institut für Astronomie der Universität Bonn, Germany), O. H. Ramírez-Agudelo (UK Astronomy Technology Centre, Royal Observatory Edinburgh, Edinburgh, UK), C. Sabín-Sanjulián (Departamento de Física y Astronomía, Universidad de La Serena, Chile), S. Simón-Díaz (Instituto de Astrofísica de Canarias, Tenerife, Spain; Departamento de Astrofísica, Universidad de La Laguna, Tenerife, Spain), F. Tramper (European Space Astronomy Centre, Madrid, Spain), P. A. Crowther (Department of Physics and Astronomy, University of Sheffield, UK), A. de Koter (Astronomical Institute Anton Pannekoek, Amsterdam University, Netherlands; Institute of Astrophysics, KU Leuven, Belgium), S. E. de Mink (Astronomical Institute Anton Pannekoek, Amsterdam University, Netherlands), P. L. Dufton (Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, Northern Ireland, UK), M. Garcia (Centro de Astrobiología, CSIC-INTA, Madrid, Spain), M. Gieles (Department of Physics, Faculty of Engineering and Physical Sciences, University of Surrey, UK), V. Hénault-Brunet (National Research Council, Herzberg Astronomy and Astrophysics, Canada; Department of Astrophysics/Institute for Mathematics, Astrophysics and Particle Physics, Radboud University, Netherlands), A. Herrero (Departamento de Física y Astronomía, Universidad de La Serena, Chile), R. G. Izzard (Department of Physics, Faculty of Engineering and Physical Sciences, University of Surrey, UK; Institute of Astronomy, The Observatories, Cambridge, UK), V. Kalari (Departamento de Astronomía, Universidad de Chile, Santiago, Chile), D. J. Lennon (European Space Astronomy Centre, Madrid, Spain), J. Maíz Apellániz (Centro de Astrobiología, CSIC–INTA, European Space Astronomy Centre campus, Villanueva de la Cañada, Spain), N. Markova (Institute of Astronomy with National Astronomical Observatory, Bulgarian Academy of Sciences, Smolyan, Bulgaria), F. Najarro (Centro de Astrobiología, CSIC-INTA, Madrid, Spain), Ph. Podsiadlowski (Department of Physics, University of Oxford, UK; Argelander-Institut für Astronomie der Universität Bonn, Germany), J. Puls (Ludwig-Maximilians-Universität München, Germany), W. D. Taylor (UK Astronomy Technology Centre, Royal Observatory Edinburgh, Edinburgh, UK), J. Th. van Loon (Lennard-Jones Laboratories, Keele University, Staffordshire, UK), J. S. Vink (Armagh Observatory, Northern Ireland, UK) and C. Norman (Johns Hopkins University, Baltimore, USA; Space Telescope Science Institute, Baltimore, USA)

    Links

    Zhang et al. research paper
    Schneider et al. research paper
    Photos of ALMA
    Photos of the VLT

    See the full ESO article here .

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

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

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  • richardmitnick 8:33 am on May 24, 2018 Permalink | Reply
    Tags: , , , , E0102-72.3: Astronomers Spot a Distant and Lonely Neutron Star, ESO Paranal VLT, ,   

    From NASA Chandra: “E0102-72.3: Astronomers Spot a Distant and Lonely Neutron Star” 

    NASA Chandra Banner

    NASA/Chandra Telescope


    From NASA Chandra

    1
    Composite

    2
    X-ray

    3
    Optical
    Credit X-ray (NASA/CXC/ESO/F.Vogt et al); Optical (ESO/VLT/MUSE & NASA/STScI)

    An isolated neutron star — with a low magnetic field and no stellar companion — has been found for the first time outside of the Milky Way galaxy.

    Astronomers used data from NASA’s Chandra X-ray Observatory, the Very Large Telescope, and other telescopes to make this discovery.

    Neutron stars are the ultra dense cores of massive stars that collapse and undergo a supernova explosion.

    Future observations at X-ray, optical, and radio wavelengths should help astronomers better understand this lonely neutron star.

    Astronomers [F.P.A. Vogt, E.S. Bartlett, I.R. Seitenzahl, M.A. Dopita, P. Ghavamian, A.J. Ruiter, J.P. Terry] have discovered a special kind of neutron star for the first time outside of the Milky Way galaxy, using data from NASA’s Chandra X-ray Observatory and the European Southern Observatory’s Very Large Telescope (VLT) in Chile.

    ESO VLT Platform at Cerro Paranal elevation 2,635 m (8,645 ft)

    Neutron stars are the ultra dense cores of massive stars that collapse and undergo a supernova explosion. This newly identified neutron star is a rare variety that has both a low magnetic field and no stellar companion.

    The neutron star is located within the remains of a supernova — known as 1E 0102.2-7219 (E0102 for short) — in the Small Magellanic Cloud, located 200,000 light years from Earth.

    Small Magellanic Cloud. 10 November 2005. ESA/Hubble and Digitized Sky Survey 2

    This new composite image of E0102 allows astronomers to learn new details about this object that was discovered more than three decades ago. In this image, X-rays from Chandra are blue and purple, and visible light data from VLT’s Multi Unit Spectroscopic Explorer (MUSE) instrument are bright red.

    ESO MUSE on the VLT

    Additional data from the Hubble Space Telescope are dark red and green.

    NASA/ESA Hubble Telescope

    Oxygen-rich supernova remnants like E0102 are important for understanding how massive stars fuse lighter elements into heavier ones before they explode. Seen up to a few thousand years after the original explosion, oxygen-rich remnants contain the debris ejected from the dead star’s interior. This debris (visible as a green filamentary structure in the combined image) is observed today hurtling through space after being expelled at millions of miles per hour.

    Chandra observations of E0102 show that the supernova remnant is dominated by a large ring-shaped structure in X-rays, associated with the blast wave of the supernova. The new MUSE data revealed a smaller ring of gas (in bright red) that is expanding more slowly than the blast wave. At the center of this ring is a blue point-like source of X-rays. Together, the small ring and point source act like a celestial bull’s eye.

    The combined Chandra and MUSE data suggest that this source is an isolated neutron star, created in the supernova explosion about two millennia ago. The X-ray energy signature, or “spectrum,” of this source is very similar to that of the neutron stars located at the center of two other famous oxygen-rich supernova remnants: Cassiopeia A (Cas A) and Puppis A. These two neutron stars also do not have companion stars.

    Cassiopeia A false color image using Hubble and Spitzer telescopes and Chandra X-ray Observatory. Credit NASA JPL-Caltech

    NASA/Spitzer Infrared Telescope

    Puppis A Supernova Remnant astrodonimaging.com

    The lack of evidence for extended radio emission or pulsed X-ray radiation, typically associated with rapidly rotating highly-magnetized neutron stars, indicates that the astronomers have detected the X-radiation from the hot surface of an isolated neutron star with low magnetic fields. About ten such objects have been detected in the Milky Way galaxy, but this is the first one detected outside our galaxy.

    But how did this neutron star end up in its current position, seemingly offset from the center of the circular shell of X-ray emission produced by the blast wave of the supernova? One possibility is that the supernova explosion did occur near the middle of the remnant, but the neutron star was kicked away from the site in an asymmetric explosion, at a high speed of about two million miles per hour. However, in this scenario, it is difficult to explain why the neutron star is, today, so neatly encircled by the recently discovered ring of gas seen at optical wavelengths.

    Another possible explanation is that the neutron star is moving slowly and its current position is roughly where the supernova explosion happened. In this case, the material in the optical ring may have been ejected either during the supernova explosion, or by the doomed progenitor star up to a few thousand years before.

    A challenge for this second scenario is that the explosion site would be located well away from the center of the remnant as determined by the extended X-ray emission. This would imply a special set of circumstances for the surroundings of E0102: for example, a cavity carved by winds from the progenitor star before the supernova explosion, and variations in the density of the interstellar gas and dust surrounding the remnant.

    Future observations of E0102 at X-ray, optical, and radio wavelengths should help astronomers solve this exciting new puzzle posed by the lonely neutron star.

    A paper describing these results was published in the April issue of Nature Astronomy.

    See the full article here .


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    NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra’s science and flight operations from Cambridge, Mass.

     
  • richardmitnick 11:32 am on May 20, 2018 Permalink | Reply
    Tags: , , , , ESO Paranal VLT,   

    From European Southern Observatory via Manu: “Stars Just Got Bigger” 


    Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

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    From European Southern Observatory

    21 July 2010
    Paul Crowther
    University of Sheffield
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    Olivier Schnurr
    Astrophysikalisches Institut Potsdam
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    ESO, La Silla, Paranal and E-ELT Press Officer
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    1
    Using a combination of instruments on ESO’s Very Large Telescope, astronomers have discovered the most massive stars to date, one weighing at birth more than 300 times the mass of the Sun, or twice as much as the currently accepted limit of 150 solar masses. The existence of these monsters — millions of times more luminous than the Sun, losing weight through very powerful winds — may provide an answer to the question “how massive can stars be?”

    The sizes of stars (annotated)
    2

    A team of astronomers led by Paul Crowther, Professor of Astrophysics at the University of Sheffield, has used ESO’s Very Large Telescope (VLT), as well as archival data from the NASA/ESA Hubble Space Telescope, to study two young clusters of stars, NGC 3603 and RMC 136a in detail.

    NASA/ESA Hubble Telescope

    NGC 3603 is a cosmic factory where stars form frantically from the nebula’s extended clouds of gas and dust, located 22 000 light-years away from the Sun (eso1005). RMC 136a (more often known as R136) is another cluster of young, massive and hot stars, which is located inside the Tarantula Nebula, in one of our neighbouring galaxies, the Large Magellanic Cloud, 165 000 light-years away (eso0613).

    Tarantula Nebula. TRAPPIST national telescope at ESO La Silla

    Large Magellanic Cloud. Adrian Pingstone December 2003

    The team found several stars with surface temperatures over 40 000 degrees, more than seven times hotter than our Sun, and a few tens of times larger and several million times brighter. Comparisons with models imply that several of these stars were born with masses in excess of 150 solar masses. The star R136a1, found in the R136 cluster, is the most massive star ever found, with a current mass of about 265 solar masses and with a birthweight of as much as 320 times that of the Sun.

    In NGC 3603, the astronomers could also directly measure the masses of two stars that belong to a double star system [1], as a validation of the models used. The stars A1, B and C in this cluster have estimated masses at birth above or close to 150 solar masses.

    Very massive stars produce very powerful outflows. “Unlike humans, these stars are born heavy and lose weight as they age,” says Paul Crowther. “Being a little over a million years old, the most extreme star R136a1 is already ‘middle-aged’ and has undergone an intense weight loss programme, shedding a fifth of its initial mass over that time, or more than fifty solar masses.”

    If R136a1 replaced the Sun in our Solar System, it would outshine the Sun by as much as the Sun currently outshines the full Moon. “Its high mass would reduce the length of the Earth’s year to three weeks, and it would bathe the Earth in incredibly intense ultraviolet radiation, rendering life on our planet impossible,” says Raphael Hirschi from Keele University, who belongs to the team.

    These super heavyweight stars are extremely rare, forming solely within the densest star clusters. Distinguishing the individual stars — which has now been achieved for the first time — requires the exquisite resolving power of the VLT’s infrared instruments [2].

    The team also estimated the maximum possible mass for the stars within these clusters and the relative number of the most massive ones. “The smallest stars are limited to more than about eighty times more than Jupiter, below which they are ‘failed stars’ or brown dwarfs,” says team member Olivier Schnurr from the Astrophysikalisches Institut Potsdam. “Our new finding supports the previous view that there is also an upper limit to how big stars can get, although it raises the limit by a factor of two, to about 300 solar masses.”

    Within R136, only four stars weighed more than 150 solar masses at birth, yet they account for nearly half of the wind and radiation power of the entire cluster, comprising approximately 100 000 stars in total. R136a1 alone energises its surroundings by more than a factor of fifty compared to the Orion Nebula cluster, the closest region of massive star formation to Earth.

    Understanding how high mass stars form is puzzling enough, due to their very short lives and powerful winds, so that the identification of such extreme cases as R136a1 raises the challenge to theorists still further. “Either they were born so big or smaller stars merged together to produce them,” explains Crowther.

    Stars between about 8 and 150 solar masses explode at the end of their short lives as supernovae, leaving behind exotic remnants, either neutron stars or black holes. Having now established the existence of stars weighing between 150 and 300 solar masses, the astronomers’ findings raise the prospect of the existence of exceptionally bright, “pair instability supernovae” that completely blow themselves apart, failing to leave behind any remnant and dispersing up to ten solar masses of iron into their surroundings. A few candidates for such explosions have already been proposed in recent years.

    Not only is R136a1 the most massive star ever found, but it also has the highest luminosity too, close to 10 million times greater than the Sun. “Owing to the rarity of these monsters, I think it is unlikely that this new record will be broken any time soon,” concludes Crowther.
    Notes

    [1] The star A1 in NGC 3603 is a double star, with an orbital period of 3.77 days. The two stars in the system have, respectively, 120 and 92 times the mass of the Sun, which means that they have formed as stars weighing, respectively, 148 and 106 solar masses.

    [2] The team used the SINFONI, ISAAC and MAD instruments, all attached to ESO’s Very Large Telescope at Paranal, Chile.

    ESO/SINFONI

    ESO ISAAC on the VLT

    ESO MAD on the VLT

    [3] (note added on 26 July 2010) The “bigger” in the title does not imply that these stars are the biggest observed. Such stars, called red supergiants, can have radii up to about a thousand solar radii, while R136a1, which is blue, is about 35 times as large as the Sun. However, R136a1 is the star with the greatest mass known to date.
    More information

    This work is presented in an article published in the Monthly Notices of the Royal Astronomical Society (“The R136 star cluster hosts several stars whose individual masses greatly exceed the accepted 150 Msun stellar mass limit”, by P. Crowther et al.).

    The team is composed of Paul A. Crowther, Richard J. Parker, and Simon P. Goodwin (University of Sheffield, UK), Olivier Schnurr (University of Sheffield and Astrophysikalisches Institut Potsdam, Germany), Raphael Hirschi (Keele University, UK), and Norhasliza Yusof and Hasan Abu Kassim (University of Malaya, Malaysia).

    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”.

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    ESO VLT Platform at Cerro Paranal elevation 2,635 m (8,645 ft)

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

    ESO/NTT at Cerro La Silla, Chile, at an altitude of 2400 metres

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

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

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    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 2:42 pm on May 16, 2018 Permalink | Reply
    Tags: , , , , ESO Paranal VLT, , , , The very distant galaxy MACS1149-JD1   

    From European Southern Observatory and ALMA Observatory: “ALMA and VLT Find Evidence for Stars Forming Just 250 Million Years After Big Bang” 

    ESO 50 Large

    From European Southern Observatory

    and

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

    From ALMA

    16 May 2018

    Nicolás Lira
    Education and Public Outreach Coordinator
    Joint ALMA Observatory, Santiago – Chile
    Phone: +56 2 2467 6519
    Cell phone: +56 9 9445 7726
    Email: nicolas.lira@alma.cl

    Masaaki Hiramatsu
    Education and Public Outreach Officer, NAOJ Chile
    Observatory
, Tokyo – Japan
    Phone: +81 422 34 3630
    Email: hiramatsu.masaaki@nao.ac.jp

    Nicolas Laporte
    University College London
    London, United Kingdom
    Tel: +44 7452 807 591
    Email: n.laporte@ucl.ac.uk

    Richard Ellis
    University College London
    London, United Kingdom
    Tel: +44 7885 403 334
    Email: richard.ellis@ucl.ac.uk

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

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory Charlottesville, Virginia – USA
    Phone: +1 434 296 0314
    Cell phone: +1 202 236 6324
    Email: cblue@nrao.edu

    1
    Astronomers have used observations from the Atacama Large Millimeter/submillimeter Array (ALMA) and ESO’s Very Large Telescope (VLT) to determine that star formation in the very distant galaxy MACS1149-JD1 started at an unexpectedly early stage, only 250 million years after the Big Bang. This discovery also represents the most distant oxygen ever detected in the Universe and the most distant galaxy ever observed by ALMA or the VLT. The results will appear in the journal Nature on 17 May 2018.

    2
    This image shows the huge galaxy cluster MACS J1149.5+223, whose light took over 5 billion years to reach us. The huge mass of the cluster is bending the light from more distant objects. The light from these objects has been magnified and distorted due to gravitational lensing. The same effect is creating multiple images of the same distant objects.
    Credit: NASA, ESA, S. Rodney (John Hopkins University, USA) and the SN team; T. Treu (University of California Los Angeles, USA), P. Kelly (University of California Berkeley, USA) and the GLASS team; J. Lotz (STScI) and the Frontier Fields team; M. Postman (STScI) and the CLASH team; and Z. Levay (STScI)

    Frontier Fields

    Gravitational Lensing NASA/ESA

    NASA/ESA Hubble Telescope

    3
    This image shows the very distant galaxy MACS1149-JD1, seen as it was 13.3 billion years ago and observed with ALMA. Credit: ALMA (ESO/NAOJ/NRAO), Hashimoto et al.


    ESOcast 161 Light: Distant galaxy reveals very early star formation.


    Zooming in on the distant galaxy MACS1149, and beyond


    Computer simulation of star formation in MACS1149-JD1


    Zooming in on the distant galaxy MACS 1149-JD1

    An international team of astronomers used ALMA to observe a distant galaxy called MACS1149-JD1. They detected a very faint glow emitted by ionised oxygen in the galaxy. As this infrared light travelled across space, the expansion of the Universe stretched it to wavelengths more than ten times longer by the time it reached Earth and was detected by ALMA. The team inferred that the signal was emitted 13.3 billion years ago (or 500 million years after the Big Bang), making it the most distant oxygen ever detected by any telescope [1]. The presence of oxygen is a clear sign that there must have been even earlier generations of stars in this galaxy.

    “I was thrilled to see the signal of the distant oxygen in the ALMA data,” says Takuya Hashimoto, the lead author of the new paper and a researcher at both Osaka Sangyo University and the National Astronomical Observatory of Japan. “This detection pushes back the frontiers of the observable Universe.”

    3
    Microwave spectrum of oxygen ions in MACS1149-JD1 detected with ALMA. It was originally infrared light with a wavelength of 88 micrometers, and ALMA detected it as microwaves with an increased wavelength of 893 micrometers due to the expansion of the Universe. Credit: Hashimoto et al. – ALMA (ESO/NAOJ/NRAO)

    In addition to the glow from oxygen picked up by ALMA, a weaker signal of hydrogen emission was also detected by ESO’s Very Large Telescope (VLT). The distance to the galaxy determined from this observation is consistent with the distance from the oxygen observation. This makes MACS1149-JD1 the most distant galaxy with a precise distance measurement and the most distant galaxy ever observed with ALMA or the VLT.

    “This galaxy is seen at a time when the Universe was only 500 million years old and yet it already has a population of mature stars,” explains Nicolas Laporte, a researcher at University College London (UCL) in the UK and second author of the new paper. “We are therefore able to use this galaxy to probe into an earlier, completely uncharted period of cosmic history.”

    For a period after the Big Bang there was no oxygen in the Universe; it was created by the fusion processes of the first stars and then released when these stars died. The detection of oxygen in MACS1149-JD1 indicates that these earlier generations of stars had been already formed and expelled oxygen by just 500 million years after the beginning of the Universe.

    But when did this earlier star formation occur? To find out, the team reconstructed the earlier history of MACS1149-JD1 using infrared data taken with the NASA/ESA Hubble Space Telescope and the NASA Spitzer Space Telescope. They found that the observed brightness of the galaxy is well-explained by a model where the onset of star formation corresponds to only 250 million years after the Universe began [2].

    NASA/Spitzer Infrared Telescope

    The maturity of the stars seen in MACS1149-JD1 raises the question of when the very first galaxies emerged from total darkness, an epoch astronomers romantically term “cosmic dawn”. By establishing the age of MACS1149-JD1, the team has effectively demonstrated that galaxies existed earlier than those we can currently directly detect.

    Richard Ellis, senior astronomer at UCL and co-author of the paper, concludes: “Determining when cosmic dawn occurred is akin to the Holy Grail of cosmology and galaxy formation. With these new observations of MACS1149-JD1 we are getting closer to directly witnessing the birth of starlight! Since we are all made of processed stellar material, this is really finding our own origins.”
    ESO Notes

    [1] ALMA has set the record for detecting the most distant oxygen several times. In 2016, Akio Inoue at Osaka Sangyo University and his colleagues used ALMA to find a signal of oxygen emitted 13.1 billion years ago. Several months later, Nicolas Laporte of University College London used ALMA to detect oxygen 13.2 billion years ago. Now, the two teams combined their efforts and achieved this new record, which corresponds to a redshift of 9.1.

    [2] This corresponds to a redshift of about 15.

    More information

    ALMA Notes

    [1] The measured redshift of galaxy MACS1149-JD1 is z=9.11. A calculation based on the latest cosmological parameters measured with Planck (H0=67.3 km/s/Mpc, Ωm=0.315, Λ=0.685: Planck 2013 Results) yields the distance of 13.28 billion light-years. Please refer to “Expressing the distance to remote objects” for the details.

    [2] The galaxy GN-z11 is thought to be located 13.4 billion light-years away based on observations with the Hubble Space Telescope (HST). But the precision of the distance measurement with HST low-resolution spectroscopy is significantly lower than that of ALMA’s measurement using a single emission line from atoms.

    These results are published in a paper entitled: “The onset of star formation 250 million years after the Big Bang”, by T. Hashimoto et al., to appear in the journal Nature on 17 May 2018.

    The research team members are: Takuya Hashimoto (Osaka Sangyo University/National Astronomical Observatory of Japan, Japan), Nicolas Laporte (University College London, United Kingdom), Ken Mawatari (Osaka Sangyo University, Japan), Richard S. Ellis (University College London, United Kingdom), Akio. K. Inoue (Osaka Sangyo University, Japan), Erik Zackrisson (Uppsala University, Sweden), Guido Roberts-Borsani (University College London, United Kingdom), Wei Zheng (Johns Hopkins University, Baltimore, Maryland, United States), Yoichi Tamura (Nagoya University, Japan), Franz E. Bauer (Pontificia Universidad Católica de Chile, Santiago, Chile), Thomas Fletcher (University College London, United Kingdom), Yuichi Harikane (The University of Tokyo, Japan), Bunyo Hatsukade (The University of Tokyo, Japan), Natsuki H. Hayatsu (The University of Tokyo, Japan; ESO, Garching, Germany), Yuichi Matsuda (National Astronomical Observatory of Japan/SOKENDAI, Japan), Hiroshi Matsuo (National Astronomical Observatory of Japan/SOKENDAI, Japan, Sapporo, Japan), Takashi Okamoto (Hokkaido University, Sapporo, Japan), Masami Ouchi (The University of Tokyo, Japan), Roser Pelló (Université de Toulouse, France), Claes-Erik Rydberg (Universität Heidelberg, Germany), Ikkoh Shimizu (Osaka University, Japan), Yoshiaki Taniguchi (The Open University of Japan, Chiba, Japan), Hideki Umehata (The University of Tokyo, Japan) and Naoki Yoshida (The University of Tokyo, Japan).

    See the full ESO article here .

    See the full ALMA article here .

    Please help promote STEM in your local schools

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    STEM Education Coalition

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

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

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    NAOJ

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

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

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

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

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

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

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

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

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

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

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

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

    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 4:19 pm on May 9, 2018 Permalink | Reply
    Tags: , , ESO Paranal VLT, ESO telescopes find first confirmed carbon-rich asteroid in Kuiper Belt, , Exiled Asteroid Discovered in Outer Reaches of Solar System,   

    From European Southern Observatory: “Exiled Asteroid Discovered in Outer Reaches of Solar System” 

    ESO 50 Large

    From European Southern Observatory

    9 May 2018

    Tom Seccull
    Postgraduate Research Student — Queen’s University, Belfast
    Belfast, United Kingdom
    Tel: +44 2890 973091
    Email: tseccull01@qub.ac.uk

    Wesley C. Fraser
    Lecturer — Queen’s University, Belfast
    Belfast, United Kingdom
    Tel: +44 28 9097 1084
    Email: wes.fraser@qub.ac.uk

    Thomas H. Puzia
    Professor — Institute of Astrophysics, Pontificia Universidad Catolica
    Santiago, Chile
    Tel: +56-2 2354 1645
    Email: tpuzia@astro.puc.cl

    Calum Turner
    ESO Assistant Public Information Officer
    Garching bei München Tel: +49 89 3200 6670
    Email: calum.turner@eso.org

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

    1

    ESO telescopes find first confirmed carbon-rich asteroid in Kuiper Belt.

    Kuiper Belt. Minor Planet Center

    The early days of our Solar System were a tempestuous time. Theoretical models of this period predict that after the gas giants formed they rampaged through the Solar System, ejecting small rocky bodies from the inner Solar System to far-flung orbits at great distances from the Sun [1]. In particular, these models suggest that the Kuiper Belt — a cold region beyond the orbit of Neptune — should contain a small fraction of rocky bodies from the inner Solar System, such as carbon-rich asteroids, referred to as carbonaceous asteroids [2].

    Now, a recent paper [see below] has presented evidence for the first reliably-observed carbonaceous asteroid in the Kuiper Belt, providing strong support for these theoretical models of our Solar System’s troubled youth. After painstaking measurements from multiple instruments at ESO’s Very Large Telescope (VLT), a small team of astronomers led by Tom Seccull of Queen’s University Belfast in the UK was able to measure the composition of the anomalous Kuiper Belt Object 2004 EW95, and thus determine that it is a carbonaceous asteroid. This suggests that it originally formed in the inner Solar System and must have since migrated outwards [3].

    The peculiar nature of 2004 EW95 first came to light during routine observations with the NASA/ESA Hubble Space Telescope by Wesley Fraser, an astronomer from Queen’s University Belfast who was also a member of the team behind this discovery.

    NASA/ESA Hubble Telescope

    The asteroid’s reflectance spectrum — the specific pattern of wavelengths of light reflected from an object — was different to that of similar small Kuiper Belt Objects (KBOs), which typically have uninteresting, featureless spectra that reveal little information about their composition.

    “The reflectance spectrum of 2004 EW95 was clearly distinct from the other observed outer Solar System objects,” explains lead author Seccull. “It looked enough of a weirdo for us to take a closer look.”

    The team observed 2004 EW95 with the X-Shooter and FORS2 instruments on the VLT. The sensitivity of these spectrographs allowed the team to obtain more detailed measurements of the pattern of light reflected from the asteroid and thus infer its composition.

    ESO X-shooter on VLT at Cerro Paranal, Chile

    ESO FORS2 VLT

    However, even with the impressive light-collecting power of the VLT, 2004 EW95 was still difficult to observe. Though the object is 300 kilometres across, it is currently a colossal four billion kilometres from Earth, making gathering data from its dark, carbon-rich surface a demanding scientific challenge.

    “It’s like observing a giant mountain of coal against the pitch-black canvas of the night sky,” says co-author Thomas Puzia from the Pontificia Universidad Católica de Chile.

    “Not only is 2004 EW95 moving, it’s also very faint,” adds Seccull. “We had to use a pretty advanced data processing technique to get as much out of the data as possible.”

    Two features of the object’s spectra were particularly eye-catching and corresponded to the presence of ferric oxides and phyllosilicates. The presence of these materials had never before been confirmed in a KBO, and they strongly suggest that 2004 EW95 formed in the inner Solar System.

    Seccull concludes: “Given 2004 EW95’s present-day abode in the icy outer reaches of the Solar System, this implies that it has been flung out into its present orbit by a migratory planet in the early days of the Solar System.”

    “While there have been previous reports of other ‘atypical’ Kuiper Belt Object spectra, none were confirmed to this level of quality,” comments Olivier Hainaut, an ESO astronomer who was not part of the team. “The discovery of a carbonaceous asteroid in the Kuiper Belt is a key verification of one of the fundamental predictions of dynamical models of the early Solar System.”
    Notes

    [1] Current dynamical models of the evolution of the early Solar System, such as the grand tack hypothesis and the Nice model, predict that the giant planets migrated first inward and then outward, disrupting and scattering objects from the inner Solar System. As a consequence, a small percentage of rocky asteroids are expected to have been ejected into orbits in the Oort Cloud and Kuiper belt.

    [2] Carbonaceous asteroids are those containing the element carbon or its various compounds. Carbonaceous — or C-type — asteroids can be identified by their dark surfaces, caused by the presence of carbon molecules.

    [3] Other inner Solar System objects have previously been detected in the outer reaches of the Solar System, but this is the first carbonaceous asteroid to be found far from home in the Kuiper Belt.

    More information

    This research was presented in a paper entitled 2004 EW95: A Phyllosilicate-bearing Carbonaceous Asteroid in the Kuiper Belt by T. Seccull et al., which appeared in The Astrophysical Journal Letters.

    The team was composed of Tom Seccull (Astrophysics Research Centre, Queen’s University Belfast, UK), Wesley C. Fraser (Astrophysics Research Centre, Queen’s University Belfast, UK) , Thomas H. Puzia (Institute of Astrophysics, Pontificia Universidad Católica de Chile, Chile), Michael E. Brown (Division of Geological and Planetary Sciences, California Institute of Technology, USA) and Frederik Schönebeck (Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Germany).

    See the full article here .

    Please help promote STEM in your local schools.
    STEM Icon

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    Visit ESO in Social Media-

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

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

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

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

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

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

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

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

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

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

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

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

    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 1:02 pm on April 14, 2018 Permalink | Reply
    Tags: Anita Zanella, , , , , ESO Paranal VLT, ,   

    From ESOblog: Women in STEM – “A Night in the Life of an Astronomer” Anita Zanella 

    ESO 50 Large

    ESOblog

    1
    Anita Zanella

    When most people picture an astronomer, they imagine a man in glasses peering up at the Universe through the lens of a huge telescope. While this might have been accurate a century ago, the life of a modern astronomer is a far cry from this stereotype. To learn more about what it’s like to spend a night at a telescope, we chatted to ESO Fellow Anita Zanella, who just wrapped up an observing run at ESO’s Very Large Telescope in Chile.

    Q: So Anita, tell us about your research and what you do at ESO.

    ____________________________________________________________
    It’s really amazing to look at these beams of light departing from inside the dome and get lost in the darkness of the night sky.
    ____________________________________________________________

    A: I’m an ESO Fellow who studies distant galaxies, trying to understand how they form and evolve through cosmic time. I’m interested in questions like: how are stars born inside galaxies? Why do some galaxies keep forming stars while others stop? Why are galaxies shaped like they are, and how does it change over time?

    I’m enjoying my time at ESO very much because it allows me to undertake my own research, but also discover so many other sides of astronomy that I did not even imagine: how observations are performed, how an observatory is run, how instruments are conceived of and built, how proposals of observations are evaluated and chosen, and so much more. It also allows me to meet and work with people from very different backgrounds, not just astronomers but also people such as instrument scientists and engineers, which is very enriching and mind-opening.

    Another cool thing is that as part of my fellowship, I have to spend 40 nights at the Paranal Observatory in Chile each year. I’m based at ESO Headquarters in Germany, so it takes a long time to reach Paranal — it’s almost a two-day trip! So I decided to have 14-night shifts, meaning I go to Chile three times a year.

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

    2
    Taken from inside the dome of the fourth Unit Telescope of ESO’s Very Large Telescope (VLT), this spectacular shot captures the VLT’s Laser Guide Star (LGS) in action
    Credit: Y. Beletsky (LCO)/ESO

    Q: What is your daily (or rather, nightly) timetable like?

    A: One of the things I really like about observing is that everything depends on nature — not only when and what to observe, but also the daily schedule of people working at the observatory. Night astronomers work every day, from sunset to sunrise. Two and a half hours before sunset we have a meeting where the daytime crew summarises what work has been done to maintain or repair the telescopes, the status of the various instruments, and what needs to be finished in the remaining hours before sunset. At that meeting, night astronomers specify what instrument they need at the beginning of the night and when they need to start observing.

    So usually I get up in the afternoon a few hours before sunset, grab a quick breakfast, and go to the afternoon meeting. It takes place in the control building, on top of the mountain just below where the telescopes are, but we sleep in the Residencia, a wonderful building, located a couple of kilometres from the telescopes. During the Chilean winter (from June to August) nights are very long, so I travel to the control building by car in about five minutes. But during the Chilean summer (from November to January) nights are short, so I usually get up early enough to have the time to hike to the meeting on the so-called “star track”, a steep path that takes you up to the control building in about 45 minutes. I love walking there, listening to the silence of the desert, watching how the shades and colours change during the day. Sometimes I can also see small animals: a lizard, a bird, some insects…

    After the meeting, we have dinner (or lunch, depending on your perspective!) at the Residencia and drive up to the mountain once again to be in control building a few minutes before sunset. Every time I can, I enjoy looking at the Sun disappearing into the ocean on the horizon, while the sky around becomes orange and pink. It is a show that never ceases to amaze me. And for the first time during my last shift, I also saw the famous green flash: it is not a legend, it’s real!

    Often we have calibrations to make at the beginning of the night. Some of them can be started about half an hour before sunset so the daytime crew takes care of them, while others have to be taken in twilight so the night astronomer is responsible for them. What time the dome first opens depends on the calibrations, but at latest it’s sunset — then the telescopes are ready to observe. Infrared observations can actually be carried out during the evening twilight, as soon as the first stars are visible, and can be used to guide the telescope in order to correct for the rotation of the Earth. Similarly, we can keep observing in the infrared in the morning twilight. But for observations at optical wavelengths, we need full dark so we have to wait for the end of twilight before observing.

    Then half an hour before sunrise, the telescope’s dome has to be closed. The daytime crew arrives at the top of the mountain, where they start their day with a meeting, to check if anything did not function during the night and agree on what needs to be done that day. But at this point, the telescope operators and night astronomers are already in bed!

    Q: Are you working the whole time, or are there times when you’re waiting around?

    A: Often, the observations last for one hour, so while I wait I usually plan what to observe afterwards, or I assess the data taken previously. I’m also always monitoring the current observations, making sure they’re running to plan. In case of bad weather (like if the humidity is above 70% or the wind is stronger than 18 metres per second), we have to close the dome, so I usually just go on with my own research. Of course, from time to time I take a break and go outside to look at the sky with my own eyes: to me, it is always more magical than looking at it through a screen!

    Q: The sky must look amazing without light pollution. Do you also have to keep the observatory dark during the night?

    A: Yes! As soon as sunset is over, blackout blinds are put over the windows in the control room, so artificial light does not pollute the observations. Similarly, blinds cover the windows of the Residencia. From this moment on, astronomers can only use torches if they walk outside, and cars have to keep their lights off. If there is full Moon it is still relatively easy to see the road and even distinguish shapes in the desert, but when the Moon is not there, the darkness is complete. The small artificial lights that help drivers to see the road are really necessary because otherwise the desert is completely swallowed by the night. At that point, the stars above us are the only source of light and it is always amazing for me to stay outside and stare at them.

    Q: Can you leave the control room once you’ve begun your shift?

    A: Well there are always at least two people at each telescope — one night astronomer and one telescope operator — and there are six consoles (or workstations) in the control room at Paranal: four for the UTs, one shared between the two survey telescopes (VST and VISTA), and one for the VLTI. So there are at least twelve people in the control building, plus visiting astronomers and trainees too. The atmosphere is always very pleasant and often funny, chatting and joking.

    Someone always has to stay at the telescope to check that everything is working properly, which means you’ll always find either the telescope operator or the night astronomer sitting in front of the console. From time to time we leave the control building to take a short walk on the platform where the telescopes are to look at the night sky, or to take visitor astronomers back to the Residencia when they have finished their observations, or to have dinner. (Eating is the last worry in Paranal — food is always available at any time of the day and night!)

    Also, sometimes astronomers are required to work on other projects during the day, so they only have to remain at the telescope until 3 am. In this case, they prepare a queue of observations for the rest of the night and the telescope operator is in charge of carrying them out. Telescope operators always have to stay for the full night, as they are the only ones allowed to move the telescopes. They are very precious because they have an incredible knowledge of how to operate telescopes and instruments!


    A 360-degree panorama of the Control Room, inside the control building, at night: when the action takes place
    Credit: ESO

    Q: Do you also get the chance to make observations for your own research?

    A: Usually I make observations for other astronomers who request them through proposals, but I was once able to observe targets for my own research. The experience was much more intense than observing for others, and it was really special to go through the whole process of conceiving an idea, writing it down in a proposal, having it accepted, taking the data at the telescope, and then using them! It was really thrilling to be at the telescope, waiting for the first image to arrive and immediately seeing if it was what I expected!

    _______________________________________________________________
    These telescopes and instruments are so complex and made of so many different pieces that it is very normal that sometimes something goes wrong.
    _______________________________________________________________

    Q: You said that the daytime crew keeps telescopes and instruments running smoothly, but what happens if something goes wrong during the night?

    A: It may happen that during the night something fails! These telescopes and instruments are so complex and made of so many different pieces that it is very normal that sometimes something goes wrong. Actually, I find it a miracle that everything keeps working smoothly almost every night! So, if something goes wrong during the observations, the night astronomer and the telescope operator leave a message for the daytime crew, who usually fix the issues the next day and the observatory is ready to go again by sunset.

    Q: The length of the night changes from summer to winter — does this affect your observations?

    A: I knew that nights in the winter are longer than in the summer, but realising it at the telescope is a whole different experience and I will never forget it! In the summer nights are short and the twilight is long, so of course, we can observe less, but we can sleep longer during the day and I usually also manage to take some time for myself — for example, taking a walk. In the winter it’s the opposite: sometimes nights are so long they become exasperating!

    On one hand, I like them, because I manage to take many observations and I feel that a lot of science is coming out of the observatory. But on the other hand, the available hours of sleep are barely enough to get enough fresh energy for the coming night, and I usually don’t manage to do anything else except observe, sleep, and eat. After 14 nights it gets a bit exhausting — but very satisfying.

    Surprisingly, it’s more difficult for me to adjust to the season change, especially when I come back from the Chilean summer (+30°C) to the German winter (-10°C). My body gets confused and it takes me a week to get used to the cold again. Switching from cold to warm weather is actually way easier for me…but I have to admit that I am a real fan of summertime!

    Q: What is your favourite part of working at Paranal?

    A: There are so many things that I like about Paranal! I always enjoy being amazed by the night sky, as well as by sunsets and sunrises. I also like to hike in the desert, watching how colours and the light change, stopping from time to time to look at the ocean on the horizon. I still find it amazing that we can see water from the top of a mountain, in the middle of the driest desert in the world! I really like to lie outside sometimes, stopping to breathe for a while and just listen to the silence of the desert.

    I like the working environment of Paranal as well: people really cooperate and work together to get this incredible observatory to function every night. They are always available to help and happy to share their knowledge, to teach you and show you around. I like the enthusiasm. It always gives me a lot of energy!

    Finally, I always find observing itself quite thrilling, waiting for the images to appear on the monitor and having the impression that science is flowing through the telescope!

    See the full article here .

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

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

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

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

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

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

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

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

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

    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 1:13 pm on March 1, 2018 Permalink | Reply
    Tags: , , , , , , ESO Paranal VLT, , Rho Ophiuchi A, Spectropolarimetry   

    From ESA via Manu: “Rho Ophiuchi A confirmed as a cosmic lighthouse” 


    Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

    27 February 2018.

    Ignazio Pillitteri
    INAF-Osservatorio Astronomico di Palermo
    Palermo, Italy
    Phone: +39 091 233 420
    pilliastropa.inaf.it

    Lida Oskinova
    Institute of Physics and Astronomy, University of Potsdam
    Potsdam, Germany
    Phone: +49 331-9775910
    lidaastro.physik.uni-potsdam.de

    Norbert Schartel
    XMM-Newton Project Scientist
    European Space Agency
    norbert.Schartelesa.int

    ESAC Communication Office
    comunicacionesac@esa.int

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    European Space Agency

    XMM-Newton detects the first X-ray flares of a massive stellar beacon.

    ESA/XMM Newton

    1
    Credit : ESA / XMM-Newton; I. Pillitteri (INAF-Astronomical Observatory of Palermo).
    This image of space observatory XMM-Newton of the ESA shows a massive star called Rho Ophiuchi A . The star, visible in the center of the frame, is in the heart of Rho Ophiuchi dark cloud, a nearby region known for actively forming new stars, located about 350 light years away.

    5
    A rich collection of colourful astronomical objects is revealed in this picturesque image of the Rho Ophiuchi cloud complex from NASA’s Wide-field Infrared Explorer, or WISE.

    NASA/WISE Telescope

    The Rho Ophiuchi cloud (pronounced ‘oh-fee-yoo-ki’ and named after a bright star in the region) is found rising above the plane of the Milky Way in the night sky, bordering the constellations Ophiuchus and Scorpius. It’s one of the nearest star-forming regions to Earth, allowing us to resolve much more detail than in more distant similar regions, like the Orion nebula.

    In 2014, a team of scientists used X – rays with the X-ray observatory XMM-Newton ESA emanating from the massive star Rho Ophiuchi A. Numerous and subsequent telescope observations showed that these periodically fluctuated as intense flames , ranging over a period of about 1.2 days as the star he turned. The team used the ESO Very Large Telescope to discover that the star has a strong magnetic field, confirming its status as cosmic X – ray lighthouse.

    ESO VLT Platform at Cerro Paranal elevation 2,635 m (8,645 ft)

    6
    The FORS instruments (Focal Reducer and low dispersion Spectrograph 2) located at ESO’s VLT. The FORS2 is in the foreground while the FORS1 is at the bottom. The two seem similar instruments but perform completely different tasks. Credit: ESO.

    This finding was unexpected given what is known about the massive stars and their behavior: it is known that sun – like stars produce flares of X rays strong, but massive stars seem to be very different. In stars more than eight solar masses, the X – ray emission is constant, and has not been observed with certainty that said star SHINES repeatedly in this part of the spectrum before observing Rho Ophiuchi A.

    It is known that sun-like stars produce powerful X-ray flares, but massive stars seem to be very different. In stars from eight solar masses, the X-ray emission is continuous and had not reached any star to issue such flares repeatedly in that part of the spectrum … Until recently observed.

    “We spent almost 40 hours observing the star with XMM-Newton and discovered something even more unexpected, recognizes Ignazio Pillitteri, INAF-Osservatorio Astronomico the di Palermo (Italy) and head of the research team. Instead of a homogeneous and continuous emission periodically pulsed X-rays toward the outside of Rho Ophiuchi A, with a variation of about 1.2 days as rotating star-just like a lighthouse X-ray! This is a new phenomenon in greater than the Sun “stars.

    Rho Ophiuchi A is much hotter and more massive than our parent star. It is not yet known how X – rays are generated in this type of stars; One possibility is a strong intrinsic magnetism, which would be observable by signs of surface magnetism. However, it remains unclear how the magnetic field would originate and how to be associated with X-ray emissions

    “We suspect that there may be a giant active magnetic point on the surface of Rho Ophiuchi A, something like a sunspot, only much larger and more stable, added Pillitteri. As the star rotates, this stain would be hidden or visible repeatedly, causing the observed X-ray pulses. However, this hypothesis is not very likely: stains stars form when a magnetic field inside comes to the surface, and we know that only one in ten massive stars have a measurable magnetic field. ”

    Furthermore, the ‘lighthouse effect’ pulse also may be due to low mass companion orbital, which would add their own and abundant X rays to light attributed to Rho Ophiuchi A . This X – ray emission power would vary due to the passage of this hypothetical smaller star ahead or behind Rho Ophiuchi A during orbit of 1.2 days. The team also considered the possibility that Rho Ophiuchi A could have an inconspicuous, small, low – mass companion in a close orbit.

    “To confirm what was the case, we hasten to obtain measurements of Rho Ophiuchi A using one of the largest ground-based observatories: the ESO VLT says Lida Oskinova, University of Potsdam (Germany) and member of the international team that carried the study. Fortunately, one of our measurements confirmed predictions by showing that X-rays were probably due to magnetic structures on the surface of the star. ”

    The measurements were made in visible light with a technique known as spectropolarimetry, which involves studying various wavelengths of polarized light emitted by a star. The data showed that Rho Ophiuchi A has a strong magnetic field, about 500 times stronger than the Sun ‘s .

    “Such a strong field may easily produce the type of detected flares, Pillitteri points. This confirms that what we found with XMM-Newton were really X-ray emissions from Rho Ophiuchi A massive stars can be magnetically active (as shown by optical observations) and that this activity can be seen in X-rays “.

    The combined data indicate that Rho Ophiuchi A is the only star of this type in which confirmed an active magnetic region on the surface that emits X – ray search for similar behavior in stars like Rho Ophiuchi A will help scientists understand the prevalence of this phenomenon and learn more about the magnetic properties of these stars.

    “This study is important for the exploration of massive stars, as there is much we do not know about these objects emphasizes Norbert Schartel, XMM-Newton scientist ESA project. By combining the extraordinary capabilities of XMM-Newton and the VLT we have managed to fit another piece of the puzzle. ”

    “In addition, it illustrates perfectly the scientific process: find something interesting or unusual, investigate and launched several hypotheses, then keep watching to find out which one is correct. It is a fantastic example of international collaboration between telescopes, both orbiting and ground, coming together to explore and explain the phenomena we see in the cosmos. ”

    7
    X-ray flares Rho Ophiuchi A. The flickering light of the massive star Rho Ophiuchi A is observed by the XMM-Newton space observatory of the ESA in 2016.

    These and earlier observations XMM-Newton showed that this star periodically throws flares X-ray of its surface as it rotates, a behavior something like a cosmic lighthouse. Follow-up observations made by the research team using the Very Large Telescope of ESO confirmed that this star has a strong magnetic field and the X-ray flares are connected to an active magnetic region on the surface of the star turns in and out of sight.

    This sequence consists of 40 frames obtained between 22 and 23 February 2016 each taken approximately one hour apart. It shows the emission of the star on the X – ray part of the spectrum; The clearer it is blue tone, stronger is the issue, and the white represents the maximum intensity. It can be seen that the intensity of X – ray emission of Rho Ophiuchi A rises sharply at the beginning and end of this sequence; This is because the data cover more than one cycle period X – ray burning star, which lasts 1.2 days.

    These findings are described in three papers published in Astronomy & Astrophysics:
    Smooth X-ray variability from ρ Ophiuchi A + B: A strongly magnetized primary B2 star? By Pillitteri et al. (2014), doi: 10.1051 / 0004-6361 / 201424243;
    The early B-type star Rho Ophiuchi A is an X-ray lighthouse of Pillitteri et al. (2017), doi: 10.1051 / 0004-6361 / 201630070; Y
    Detection of magnetic field in the B2 star ρ Oph A with ESO FORS2 of Pillitteri et al. (2018), doi: 10.1051 / 0004-6361 / 201732078.

    See the full article here .

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

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  • richardmitnick 7:09 am on February 27, 2018 Permalink | Reply
    Tags: , , , , ESO Paranal VLT, , , Stars Around the Milky Way: Cosmic Space Invaders or Victims of Galactic Eviction?, UCO Keck Observatory   

    From Keck: “Stars Around the Milky Way: Cosmic Space Invaders or Victims of Galactic Eviction?” 

    Keck Observatory, Maunakea, Hawaii, USA.4,207 m (13,802 ft) above sea level, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland


    Keck Observatory

    February 26, 2018
    Mari-Ela Chock, Communications Officer
    W. M. Keck Observatory
    (808) 554-0567
    mchock@keck.hawaii.edu

    1
    Figure 1: The Milky Way galaxy, perturbed by the tidal interaction with a dwarf galaxy, as predicted by N-body simulations. The locations of the observed stars above and below the disk, which are used to test the perturbation scenario, are indicated. Credit: T. MUELLER/C. LAPORTE/NASA/JPL-CALTECH

    An international team of astronomers led by the Max Planck Institute for Astronomy (MPIA) has made a surprising discovery about the birthplace of groups of stars located in the halo of our Milky Way galaxy.

    2
    Milky Way Jalo. NASA / ESA / A. Feild.

    These halo stars are grouped together in giant structures that orbit the center of our galaxy, above and below the flat disk of the Milky Way.

    Milky Way NASA/JPL-Caltech /ESO R. Hurt

    Researchers thought they may have formed from debris left behind by smaller galaxies that invaded the Milky Way in the past.

    But in a study published today in the journal Nature, astronomers now have compelling evidence showing that some of these halo structures actually originate from the Milky Way’s disk itself, but were kicked out.

    “This phenomenon is called galactic eviction,” said co-author Judy Cohen, Kate Van Nuys Page Professor of Astronomy at Caltech. “These structures are pushed off the plane of the Milky Way when a massive dwarf galaxy passes through the galactic disk. This passage causes oscillations, or waves, that eject stars from the disk, either above or below it depending on the direction that the perturbing mass is moving.”

    “The oscillations can be compared to sound waves in a musical instrument,” said lead author Maria Bergemann of MPIA. “We call this ‘ringing’ in the Milky Way galaxy ‘galactoseismology,’ which has been predicted theoretically decades ago. We now have the clearest evidence for these oscillations in our galaxy’s disk obtained so far!”

    For the first time, Bergemann’s team presented detailed chemical abundance patterns of these halo stars using the W. M. Keck Observatory on Maunakea, Hawaii.

    “The analysis of chemical abundances is a very powerful test, which allows, in a way similar to the DNA matching, to identify the parent population of the star. Different parent populations, such as the Milky Way disk or halo, dwarf satellite galaxies or globular clusters, are known to have radically different chemical compositions. So once we know what the stars are made of, we can immediately link them to their parent populations,” said Bergemann.

    The scientists investigated 14 stars located in two different halo structures – the Triangulum-Andromeda (Tri-And) and the A13 stellar overdensities. These two structures lie on opposite sides of the Milky Way disk; about 14,000 light years above and below the Galactic plane (see Figure 1).

    The team obtained spectra of the halo stars using Keck Observatory’s High-Resolution Echelle Spectrometer (HIRES).

    Keck HIRES, Keck Observatory, Maunakea, Hawaii, USA.

    “The high throughput and high spectral resolution of HIRES were crucial to the success of the observations of the stars in the outer part of the Milky Way,” said Cohen. “Another key factor was the smooth operation of Keck Observatory; good pointing and smooth operation allows one to get spectra of more stars in only a few nights of observation. The spectra in this study were obtained in only one night of Keck time, which shows how valuable even a single night can be.”

    The team also obtained a spectrum of one additional star taken with the European Southern Observatory’s Very Large Telescope (VLT) in Chile.

    ESO VLT Platform at Cerro Paranal elevation 2,635 m (8,645 ft)

    When comparing the chemical compositions of these stars with the ones found in other cosmic structures, the scientists were surprised to find that the chemical compositions are almost identical, both within and between these groups, and closely match the abundance patterns of the Milky Way outer disk stars.

    This provides compelling evidence that the halo stars most likely originate from the Galactic thin disk (the younger part of Milky Way, strongly concentrated towards the Galactic plane) itself.

    These findings are very exciting because they indicate the Milky Way’s disk and its dynamics are significantly more complex than previously thought.

    “We showed that it may be fairly common for groups of stars in the disk to be relocated to more distant realms within the Milky Way – having been ‘kicked out’ by an invading satellite galaxy. Similar chemical patterns may also be found in other galaxies, indicating a potential galactic universality of this dynamic process,” said co-author Allyson Sheffield of LaGuardia Community College/CUNY.

    As a next step, the astronomers plan to analyse the spectra of additional stars in the Tri-And and A13 overdensities, as well as stars in other stellar structures further away from the disk. They also plan to determine masses and ages of these stars so they can constrain the time limits of when this galactic eviction took place.

    ABOUT HIRES

    The High-Resolution Echelle Spectrometer (HIRES) produces spectra of single objects at very high spectral resolution, yet covering a wide wavelength range. It does this by separating the light into many “stripes” of spectra stacked across a mosaic of three large CCD detectors. HIRES is famous for finding planets orbiting other stars. Astronomers also use HIRES to study distant galaxies and quasars, finding clues to the Big Bang. HIRES was made possible by funding generously provided by the William J. and Dorothy K. O’Neill Foundation.

    See the full article here .

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    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.


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  • richardmitnick 2:15 pm on January 25, 2018 Permalink | Reply
    Tags: , , , , ESO Paranal VLT, First gas jet detection from massive young star outside our galaxy,   

    From STFC: “First gas jet detection from massive young star outside our galaxy” 


    STFC

    25 January 2018
    No writer credit found

    ESO VLT Platform at Cerro Paranal elevation 2,635 m (8,645 ft)

    An international team of astronomers, including two STFC scientists, have made the very first detection of a jet from a very young, massive star in a galaxy that is not our own.

    The paper [Nature] was co-authored by Pamela Klaassen, instrument scientist at the STFC’s Edinburgh site, the UK Astronomy Technology Centre (UK ATC), and UK ATC’s Head of Science Chris Evans. [Other authors credited: Anna F. McLeod, Megan Reiter, Rolf Kuiper, Pamela D. Klaassen, Christopher J. Evans.]

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    Marsden Fellow Dr Anna McLeod, of UC’s School of Physical and Chemical Sciences, says this discovery will drive significant advancement in the field of star formation.

    Dr Klaassen said: “With this observation, we see that the details of star formation we see in our galaxy are also possible elsewhere, even when the conditions and material available are quite different to those we’re used to.”

    Stars like the Sun are constantly forming in our galaxy and further afield in more distant galaxies. They form in predictable ways, emerging from their natal environment often surrounded by a system of planets which formed from a disk.

    Stars with more mass, upwards of eight times that of the Sun, are much rarer and their formation remains something of a mystery. These more massive stars form deep within their natal clouds of gas and dust and are generally too obscured to be visible with optical telescopes. Under the right conditions, it is sometimes possible to see a jet or outflow of expelled gas, but only if it’s powerful enough to push out of the natal cloud. These narrow streams of gas move away from the forming star at high speeds – and often the bigger the star, the bigger and faster the jet.

    Astronomical instruments like MUSE (Multi Unit Spectroscopic Explorer) on the European Southern Observatory’s Very Large Telescope (ESO VLT) in Chile are vital for understanding these jets of gas.

    ESO MUSE on the VLT

    Dr Klaassen said: “In this paper, we present the first evidence for such a jet from a young stellar object in another galaxy, the nearby Large Magellanic Cloud (LMC).

    Large Magellanic Cloud. Adrian Pingstone December 2003

    “The LMC has a lower abundance of ‘metals’ (atoms heavier than hydrogen and helium) than our own galaxy, which means that the environment of the young star is less opaque than an equivalent region in the Milky Way helping make this detection robust.

    “The jet spans about 36 light years (or 11 parsecs), which makes it among the largest jets of its kind ever found. The star powering the jet appears to be about 12 times as massive as the Sun, and its velocity structure was revealed by the high spectral resolution of MUSE – we know which part of the jet is angled towards us, and which is angled away.”

    The data used for this work comes from the VLT in Chile’s Atacama Desert, which is among the largest optical telescopes in the world and is one of the most competitive telescopes on which to obtain precious observing time.

    It is only with this kind of instrument that this could be done; regular instruments would not have detected the jet. The VLT can detect objects roughly four billion times fainter than can be detected with the naked eye.

    The project team was led by Dr Anna McLeod from the University of Canterbury in New Zealand, who says this discovery will drive significant advancement in the field of star formation: “The formation mechanism of massive stars was predicted three decades ago and involved an accretion disk, similar to how their lower-mass siblings form. Over the years numerical simulations were produced which support this scenario. Recently there has been some initial observational evidence that this might indeed be the case. In our paper, we present compelling evidence that high-mass stars form in a similar way to Sun-like stars.

    “We have detected a very young and still forming massive star – a so-called young stellar object – which is launching a bipolar jet. The jet is direct evidence for what we call an accretion disk, i.e. a disk around the equator of the star through which the star is gathering matter and thus growing, which is what we see in low-mass stars.”

    This discovery brings direct evidence that massive stars up to 12 times that of our Sun form like low-mass stars.

    More information is available on the University of Canterbury website.

    See the full article here .

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    We are a world-leading multi-disciplinary science organisation, and our goal is to deliver economic, societal, scientific and international benefits to the UK and its people – and more broadly to the world. Our strength comes from our distinct but interrelated functions:

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    We support an academic community of around 1,700 in particle physics, nuclear physics, and astronomy including space science, who work at more than 50 universities and research institutes in the UK, Europe, Japan and the United States, including a rolling cohort of more than 900 PhD students.

    STFC-funded universities produce physics postgraduates with outstanding high-end scientific, analytic and technical skills who on graduation enjoy almost full employment. Roughly half of our PhD students continue in research, sustaining national capability and creating the bedrock of the UK’s scientific excellence. The remainder – much valued for their numerical, problem solving and project management skills – choose equally important industrial, commercial or government careers.

    Our large-scale scientific facilities in the UK and Europe are used by more than 3,500 users each year, carrying out more than 2,000 experiments and generating around 900 publications. The facilities provide a range of research techniques using neutrons, muons, lasers and x-rays, and high performance computing and complex analysis of large data sets.

    They are used by scientists across a huge variety of science disciplines ranging from the physical and heritage sciences to medicine, biosciences, the environment, energy, and more. These facilities provide a massive productivity boost for UK science, as well as unique capabilities for UK industry.

    Our two Campuses are based around our Rutherford Appleton Laboratory at Harwell in Oxfordshire, and our Daresbury Laboratory in Cheshire – each of which offers a different cluster of technological expertise that underpins and ties together diverse research fields.

    The combination of access to world-class research facilities and scientists, office and laboratory space, business support, and an environment which encourages innovation has proven a compelling combination, attracting start-ups, SMEs and large blue chips such as IBM and Unilever.

    We think our science is awesome – and we know students, teachers and parents think so too. That’s why we run an extensive Public Engagement and science communication programme, ranging from loans to schools of Moon Rocks, funding support for academics to inspire more young people, embedding public engagement in our funded grant programme, and running a series of lectures, travelling exhibitions and visits to our sites across the year.

    Ninety per cent of physics undergraduates say that they were attracted to the course by our sciences, and applications for physics courses are up – despite an overall decline in university enrolment.

     
  • richardmitnick 12:45 pm on October 12, 2017 Permalink | Reply
    Tags: , , , , , ESO Paranal VLT, , , Prolate rotator galaxies   

    From Max Planck Institute for Astronomy: “Astronomers discover unusual spindle-like galaxies” 

    Max Planck Institute for Astronomy

    Max Planck Institute for Astronomy

    October 12, 2017
    Science Contact
    Athanasia Tsatsi
    tsatsi@mpia-hd.mpg.de

    Public Information Officer
    Markus Pössel
    Public Information Officer
    Phone:(+49|0) 6221 528-261
    poessel@hda-hd.de

    Galaxies are majestic, rotating wheels of stars? Not in the case of the spindle-like galaxies studied by Athanasia Tsatsi (Max Planck Institute for Astronomy) and her colleagues. Using the CALIFA survey, the astronomers found that these slender galaxies, which rotate along their longest axis, are much more common than previously thought. The new data allowed the astronomers to create a model for how these unusual galaxies probably formed, namely out of a special kind of merger of two spiral galaxies. The results have been published in the journal Astronomy & Astrophysics.

    1
    An elliptical galaxy in prolate rotation. The galaxy resembles the shape of a cigar, with its stars rotating around the galaxy’s long axis, similar to a spindle. the background image is a snapshot of a simulation by A. Tsatsi and colleagues.
    Image: J. Chang, PMO / T. Müller, HdA

    When most people think of galaxies, they think of majestic spiral galaxies like that of our home galaxy, the Milky Way: billions of stars, rotating in a flat disk similar to the way that a wheel rotates around its central axis. But there is another kind of galaxy, which used to be thought very rare: so-called prolate rotators, each shaped like a cigar, which rotates along its long axis, like a spindle.

    Now, a group of astronomers led by Athanasia Tsatsi of the Max Planck Institute for Astronomy has completed a thorough study of these cosmic spindles. Using data from the CALIFA survey, a systematic study that examined the velocity structure of more than 600 galaxies, the astronomers discovered eight new prolate rotating galaxies, almost doubling the total known number of such galaxies (from 12 to 20). Cosmic spindles are considerably less rare than astronomers had thought!

    Given the high quality of their data, the astronomers were able to propose a plausible explanation for how these cosmic spindles come into existence. In general, galaxies grow when they merge with other galaxies. Several mergers with smaller galaxies have made our own Milky Way the stately disk it is today. To make a cosmic spindle, two large disk galaxies need to collide at right angles, as shown in this animation:


    Movie: J. Chang, PMO / T. Müller, HdA

    The formation of an elliptical galaxy in prolate rotation. The mechanism shown here was proposed by Athanasia Tsatsi and her colleagues in order to explain the recent discoveries of galaxies of this kind with the CALIFA survey. The formation involves a polar merger of two spiral galaxies. One of the spiral galaxies develops a marked elongated structure (a “bar,” to use the technical term) before the merger, which gives the resulting elliptical galaxy its cigar-like (prolate) shape. The stars of the second spiral galaxy end up orbiting around the bar of the first companion. Together they form a cigar-shaped elliptical galaxy that rotates like a spindle around its long axis.

    As the galaxies begin to interact via gravitational attraction, one of them forms a bar: an elongated structure near the center. That bar becomes the cigar-like shape of the merged galaxy, while the orbiting stars of the other galaxy imbue the merged galaxy with its overall sense of rotation.

    The results are an interesting piece of the puzzle, explaining a likely formation scenario for an unusual, but not all that uncommon type of galaxy. Tsatsi’s team of researchers having put to good use all the information contained in the CALIFA data, the ball is now in the court of the observing astronomers again: the merger simulations make some additional predictions for the detailed properties of prolate rotators. These cannot be distinguished with the current observations, but could be tested with instruments like MUSE, the Multi Unit Spectral Explorer at ESO’s Very Large Telescope, an 8-meter-telescope at Paranal Observatory in Chile.

    ESO MUSE on the VLT


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

    The team members are Athanasia Tsatsi, Glenn van de Ven, and Andrea V. Macciò (also New York University Abu Dhabi) in collaboration with Mariya Lyubenova (University of Groningen, Netherland, now at ESO), J. Chang (Purple Mountain Observatory, Nanjing, China), J. A. L. Aguerri and J. Falcón-Barroso (both Instituto de Astrofísica de Canarias and Universidad de La Laguna, Tenerife, Spain).

    Calar Alto Observatory was founded in 1979 and is located in Andalusia, Spain.

    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

    It is operated jointly by the Max Planck Institute for Astronomy (MPIA) and the Astrophysical Institute of Andalusia (IAA-CSIC, Granada, Spain). The Observatory has granted 250 observing nights over the course of three years, using the 3.5 metre telescope for the CALIFA survey. This project is a joint effort of more than 80 scientists from 25 different research institutes in 13 different countries world wide.

    The integral field spectrograph used for the CALIFA survey at Calar Alto Observatory, PMAS (in a special configuration called PPAK), uses more than 350 optical fibres to cover a field of view of one square arcminute (equivalent to the apparent size of a 1 euro coin placed at a distance of approximately 80 metres). This allows a complete extended object, such as a galaxy, to be fully mapped in detail in just one exposure.

    For the CALIFA survey, care has been taken to select the possible observation targets at random from the overall population of galaxies. In that way, the galaxies under study should be representative of the whole: Statistical conclusions from the analysis of their data should thus allow astronomers to draw conclusions about local galaxies in general.

    The CALIFA member institutions are: Astrophysical Institute, Academy of Sciences of the Czech Republic, Prague; Australian Astronomical Observatory, Australia; Centro Astronómico Hispano Alemán, Spain; Centro de Astrofísica da Universidade do Porto, Portugal; Institut d’Astrophysique de Paris, France; Instituto de Astrofisica de Andalucia, Spain; Instituto de Astrofisica de Canarias, Spain; Instituto de Física de Cantabria, Spain; Laboratoire d’Astrophysique de Marseille, France; Leibniz Institut für Astrophysik, Potsdam, Germany; Max Planck Institute for Astronomy, Heidelberg, Germany; Observatoire de Paris, France; Peking University – Kavli Institute for Astronomy and Astrophysics, China; Royal Military College of Canada, Canada; Tianjin Normal University, China; Universidad Autónoma de Madrid, Spain; Universidad de Complutense de Madrid, Spain; Universidad de Granada, Spain; Universidad de Zaragoza, Spain; University of Bochum, Germany; University of Cambridge, UK; University of Copenhagen – Dark Cosmology Centre, Denmark; University of Edingurgh, UK; University of Groningen – Kapteyn Astronomical Institute, The Netherlands; University of Heidelberg – Landessternwarte Königstuhl, Germany; University of Lisbon, Portugal; University of Missouri-Kansas City, USA; University of Porto, Portugal; University of Sidney, Australia; University of Vienna, Austria

    See the full article here .

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