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  • richardmitnick 11:41 am on April 5, 2018 Permalink | Reply
    Tags: , , , , Dead Star Circled by Light, ESO VLT, , ,   

    From ESO: “Dead Star Circled by Light” 

    ESO 50 Large

    European Southern Observatory

    5 April 2018
    Frédéric P. A. Vogt
    ESO Fellow
    Santiago, Chile
    Email: fvogt@eso.org

    Elizabeth S. Bartlett
    ESO Fellow
    Santiago, Chile
    Email: ebartlet@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
    New images from ESO’s Very Large Telescope in Chile and other telescopes reveal a rich landscape of stars and glowing clouds of gas in one of our closest neighbouring galaxies, the Small Magellanic Cloud. The pictures have allowed astronomers to identify an elusive stellar corpse buried among filaments of gas left behind by a 2000-year-old supernova explosion. The MUSE instrument was used to establish where this elusive object is hiding, and existing Chandra X-ray Observatory data confirmed its identity as an isolated neutron star.

    ESO MUSE on the VLT

    NASA/Chandra Telescope

    Spectacular new pictures, created from images from both ground- and space-based telescopes [1], tell the story of the hunt for an elusive missing object hidden amid a complex tangle of gaseous filaments in the Small Magellanic Cloud, about 200 000 light-years from Earth.

    New data from the MUSE instrument on ESO’s Very Large Telescope in Chile has revealed a remarkable ring of gas in a system called 1E 0102.2-7219, expanding slowly within the depths of numerous other fast-moving filaments of gas and dust left behind after a supernova explosion. This discovery allowed a team led by Frédéric Vogt, an ESO Fellow in Chile, to track down the first ever isolated neutron star with low magnetic field located beyond our own Milky Way galaxy.

    The team noticed that the ring was centred on an X-ray source that had been noted years before and designated p1. The nature of this source had remained a mystery. In particular, it was not clear whether p1 actually lies inside the remnant or behind it. It was only when the ring of gas — which includes both neon and oxygen — was observed with MUSE that the science team noticed it perfectly circled p1. The coincidence was too great, and they realised that p1 must lie within the supernova remnant itself. Once p1’s location was known, the team used existing X-ray observations of this target from the Chandra X-ray Observatory to determine that it must be an isolated neutron star, with a low magnetic field.

    In the words of Frédéric Vogt: “If you look for a point source, it doesn’t get much better than when the Universe quite literally draws a circle around it to show you where to look.”

    When massive stars explode as supernovae, they leave behind a curdled web of hot gas and dust, known as a supernova remnant. These turbulent structures are key to the redistribution of the heavier elements — which are cooked up by massive stars as they live and die — into the interstellar medium, where they eventually form new stars and planets.

    Typically barely ten kilometres across, yet weighing more than our Sun, isolated neutron stars with low magnetic fields are thought to be abundant across the Universe, but they are very hard to find because they only shine at X-ray wavelengths [2]. The fact that the confirmation of p1 as an isolated neutron star was enabled by optical observations is thus particularly exciting.

    Co-author Liz Bartlett, another ESO Fellow in Chile, sums up this discovery: “This is the first object of its kind to be confirmed beyond the Milky Way, made possible using MUSE as a guidance tool. We think that this could open up new channels of discovery and study for these elusive stellar remains.”
    Notes

    [1] The image combines data from the MUSE instrument on ESO’s Very Large Telescope in Chile and the orbiting the NASA/ESA Hubble Space Telescope and NASA Chandra X-Ray Observatory.

    NASA/ESA Hubble Telescope

    [2] Highly-magnetic spinning neutron stars are called pulsars. They emit strongly at radio and other wavelengths and are easier to find, but they are only a small fraction of all the neutron stars predicted to exist.

    More information

    This research was presented in a paper entitled Identification of the central compact object in the young supernova remnant 1E 0102.2-7219, by Frédéric P. A. Vogt et al., in the journal Nature Astronomy.

    The team is composed of Frédéric P. A. Vogt (ESO, Santiago, Chile & ESO Fellow), Elizabeth S. Bartlett (ESO, Santiago, Chile & ESO Fellow), Ivo R. Seitenzahl (University of New South Wales Canberra, Australia), Michael A. Dopita (Australian National University, Canberra, Australia), Parviz Ghavamian (Towson University, Baltimore, Maryland, USA), Ashley J. Ruiter (University of New South Wales Canberra & ARC Centre of Excellence for All-sky Astrophysics, Australia) and Jason P. Terry (University of Georgia, Athens, USA).

    See the full article here .

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

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

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

    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

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  • richardmitnick 9:53 am on March 26, 2018 Permalink | Reply
    Tags: , , , , ESO VLT,   

    From NASA Chandra: “NGC 1365: Chandra Sees Remarkable Eclipse of Black Hole” April 12, 2007 

    NASA Chandra Banner

    NASA/Chandra Telescope


    NASA Chandra

    April 12, 2007 [From before this blog]

    1
    Credit X-ray: NASA/CXC/CfA/INAF/Risaliti Optical: ESO/VLT

    Chandra observations of the galaxy NGC 1365 have captured a remarkable eclipse of the supermassive black hole at its center. A dense cloud of gas passed in front of the black hole, which blocked high-energy X-rays from material close to the black hole. This serendipitous alignment allowed astronomers to measure the size of the disk of material around the black hole, a relatively tiny structure on galactic scales. The Chandra image (shown in the inset) contains a bright X-ray source in the middle, which reveals the position of the supermassive black hole. An optical view of the galaxy from the European Southern Observatory’s Very Large Telescope shows the context of the Chandra data.

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

    NGC 1365 contains a so-called active galactic nucleus, or AGN. Scientists believe that the black hole at the center of the AGN is fed by a steady stream of material, presumably in the form of a disk. Material just about to fall into a black hole should be heated to millions of degrees before passing over the event horizon, or point of no return. The process causes the disk of gas around the central black hole in NGC 1365 to produce copious X-rays, but the structure is much too small to resolve directly with a telescope. However, astronomers were able to measure the disk’s size by observing how long it took for the black hole to go in and out of the eclipse. This was revealed during a series of observations of NGC 1365 obtained every two days over a period of two weeks in April 2006. During five of the observations, high-energy X-rays from the central X-ray source were visible, but in the second one — corresponding to the eclipse — they were not.

    No science paper cited.

    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 11:08 am on January 31, 2018 Permalink | Reply
    Tags: , , , , , ESO GRAAL, , ESO VLT, Sharper Images for VLT Infrared Camera   

    From ESO: “Sharper Images for VLT Infrared Camera” 

    ESO 50 Large

    European Southern Observatory

    30 January 2018
    Harald Kuntschner
    ESO, AOF Project Scientist
    Garching bei München, Germany
    Tel: +49 89 3200 6465
    Email: hkuntsch@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
    This image of the dramatic star formation region 30 Doradus, also known as the Tarantula Nebula, was created from a mosaic of images taken using the HAWK-I instrument working with the Adaptive optics Facility of ESO’s Very Large Telescope in Chile. The stars are significantly sharper than the same image without adaptive optics being used, and fainter stars can be seen.

    ESO’s Very Large Telescope (VLT) now has a second instrument working with the powerful Adaptive Optics Facility (AOF). The infrared instrument HAWK-I (High Acuity Wide-field K-band Imager) [1] is now also benefiting from sharper images and shorter exposure times. This follows the successful integration of the AOF with MUSE (the Multi Unit Spectroscopic Explorer).

    ESO HAWK-I on the ESO VLT

    ESO MUSE on the VLT

    The Adaptive Optics Facility (AOF) is a long-term project that is nearing completion on ESO’s Very Large Telescope (VLT). It provides adaptive optics correction for all the instruments attached to one of the VLT Unit Telescopes (UT4, also known as Yepun).

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

    Adaptive optics works to compensate for the blurring effect of the Earth’s atmosphere. This upgrade now enables HAWK-I to obtain sharper images, needing shorter exposure times than before to obtain similar results. By using the AOF, astronomers can now get good image quality with HAWK-I, even when the weather conditions are not perfect.

    Following a series of tests of the new system, the commissioning team of astronomers and engineers were rewarded with a series of spectacular images, including one of the Tarantula Nebula star-forming region in the Large Magellanic Cloud.

    The AOF, which made these observations possible, is composed of many parts working together. These include the Four Laser Guide Star Facility (4LGSF) and the UT4’s very thin deformable secondary mirror, which is able to change its shape [2] [3]. The 4LGSF shines four 22-watt laser beams into the sky to make sodium atoms in the upper atmosphere glow as bright points of light, forming artificial guide stars.

    Sensors in the adaptive optics module GRAAL (GRound layer Adaptive optics Assisted by Lasers) use these artificial guide stars to determine the atmospheric conditions.

    ESO Graal

    One thousand times per second, the AOF system calculates the correction that must be applied to the telescope’s deformable secondary mirror to compensate for the atmospheric disturbance.

    GRAAL corrects for the turbulence in the layer of atmosphere up to about 500 metres above the telescope — the “ground layer”. Depending on the conditions, atmospheric turbulence occurs at all altitudes, but studies have shown that the largest fraction of the disturbance occurs in the ground layer of the atmosphere.

    The corrections applied by the AOF rapidly and continuously improve the image quality by concentrating the light to form sharper images, allowing HAWK-I to resolve finer details and detect fainter stars than previously possible.

    MUSE and HAWK-I are not the only instruments that will benefit from the AOF; in future, the new instrument ERIS will be installed on the VLT. The AOF is also a pathfinder for adaptive optics on ESO’s Extremely Large Telescope (ELT).

    Notes

    [1] HAWK-I is a wide-field imager, an instrument that takes images of the sky in infrared wavelengths. This allows it to see inside interstellar dust and gas, which blocks optical light. The instrument uses four imaging chips simultaneously to achieve such a large field of view, capturing a wealth of information.

    [2] At just over one metre in diameter, this is the largest adaptive optics mirror in operation and demanded cutting-edge technology to make it. It was mounted on UT4 in 2016 (ann16078) to replace the telescope’s original conventional secondary mirror.

    [3] Other tools to optimise the operation of the AOF have been developed and are now operational. These include an extension of the Astronomical Site Monitor software that monitors the atmosphere to determine the altitude at which the turbulence is occurring, and the Laser Traffic Control System (LTCS) that prevents other telescopes looking into the laser beams or spots and potentially affecting their observations.

    See the full article here .

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

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    ESO Bloc Icon

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

     
  • richardmitnick 2:27 pm on December 25, 2017 Permalink | Reply
    Tags: Astronomers Find Galaxy Cluster with Mass of Two Quadrillion Suns, , , , , ESO VLT, ,   

    From Science News: “Astronomers Find Galaxy Cluster with Mass of Two Quadrillion Suns” 

    SciNews

    Dec 25, 2017

    NASA and ESO astronomers have joined forces to observe RCS2 J2327-0204, one of the most massive galaxy clusters known at its distance or beyond.

    1
    The galaxy cluster RCS2 J2327-0204. Image credit: ESO / NASA / ESA / Hubble.

    RCS2 J2327-0204 is an extremely massive cluster of galaxies located approximately 6 billion light-years away.

    Massive objects such as RCS2 J2327-0204 have such a strong influence on their surroundings that they visibly warp the space around them. This effect is known as gravitational lensing.

    Gravitational Lensing NASA/ESA

    In this way, they cause the light from more distant objects to be bent, distorted, and magnified, allowing us to see galaxies that would otherwise be far too distant to detect.

    Gravitational lensing is one of the predictions of Albert Einstein’s theory of general relativity.

    Strong lensing produces stunning images of distorted galaxies and sweeping arcs; both of which can be seen in this image.

    Weak gravitational lensing, on the other hand, is more subtle, hardly seen directly in an image, and is mostly studied statistically — but it provides a way to measure the masses of cosmic objects, as in the case of this cluster.

    This image of RCS2 J2327-0204 is a composite of observations from the HAWK-I instrument on ESO’s Very Large Telescope and the Advanced Camera for Surveys (ACS) instrument on the NASA/ESA Hubble Space Telescope.

    ESO HAWK-I on the ESO VLT


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

    NASA/ESA Hubble ACS

    NASA/ESA Hubble Telescope

    It demonstrates an impressively detailed collaborative approach to studying weak lensing in the cosmos.

    The astronomers found RCS2 J2327-0204 to contain the mass of two quadrillion Suns.

    The diffuse blue and white image covering the picture shows a mass map. It is connected to the amount of mass thought to be contained within each region.

    See the full article here .

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  • richardmitnick 8:43 am on October 4, 2017 Permalink | Reply
    Tags: , , , , , ESO VLT,   

    From CNRS: “MATISSE to shed light on the formation of Earth and planets” 

    CNRS bloc

    Centre Nationnal de la Recherche Scientifique [The National Center for Scientific Research ]

    25 September 2017
    Contacts:
    Researcher Observatoire Côte d’Azur
    Bruno Lopez
    bruno.lopez@oca.eu

    Press:
    Observatoire Côte d’Azur
    Marc Fulconis
    marc.fulconis@oca.eu

    CNRS Press Office
    Julien Guillaume
    T +33 1 44 96 46 35
    julien.guillaume@cnrs-dir.fr

    The MATISSE instrument is ready to be sent to Chile, where in the next few weeks it will be installed on the Very Large Telescope (VLT), the world’s most powerful astronomical observatory.

    ESO CNRS VLT Matisse Multi-AperTure mid-Infrared SpectroScopic Experiment

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

    This achievement is the outcome of fifteen years of development, including a final year of testing at the Laboratoire J.-L. Lagrange (Observatoire Côte d’Azur/CNRS/Université de Nice Sophia-Antipolis). The instrument, for which France is responsible under the auspices of the European Southern Observatory (ESO), is international in scope. By observing the protoplanetary disks that surround young stars, the MATISSE project should improve our understanding of the formation of the Earth and of planets in general.

    MATISSE is one of the few projects for which France has responsibility under the auspices of the ESO. In early October 2017, the MATISSE (Multi AperTure mid-Infrared SpectroScopic Experiment) instrument will travel to the Atacama desert in Chile to be installed on the ESO’s Very Large Telescope (VLT), the world’s most powerful astronomical observatory. Eight to ten months’ performance validation observing the sky under real conditions will then be required before the instrument is made available to the international astronomical community.

    With MATISSE, one of the major goals of researchers is to observe protoplanetary disks in order to understand the formation of our own planet and that of planets in general. To achieve this, the instrument will enable astronomers to observe the sky with unprecedented resolution in the mid-infrared region—at wavelengths of 3 to 13 micrometers—and to combine the light from four of the VLT’s eight telescopes at Cerro Paranal, Chile, including the four large eight-meter telescopes. Using the instrument it will be possible to observe the dust and gas surrounding young stars that make up the basic building blocks from which planets form. The environments of stars younger than our own Sun, which have been difficult to observe until now, should shed light on the conditions under which different types of planets form: gas giants like Jupiter, and smaller rocky planets like Earth.

    MATISSE will operate in the same range of wavelengths as the James Webb Space Telescope, which will be launched in 2019 by NASA, and to which it is complementary. NASA researchers are already collaborating with the MATISSE consortium in order to step up joint research.

    NASA/ESA/CSA Webb Telescope annotated

    A number of European organizations were involved in developing the project: the Observatoire de la Côte d’Azur (OCA) and the CNRS in France, the MPIA, MPIfR and ESO in Germany, and NOVA-ASTRON in the Netherlands.

    Status

    Preliminary acceptance Chile: 2019
    First light on telescope: Early 2018
    Now
    Preliminary acceptance Europe: September 2017
    Final Design Review, March 2012
    Optical and Cryogenics Final Design Review, September 2011
    Preliminary Design Review, December 2010

    Baseline Specification
    Requirement
    Optical Throughput 15% (goal 25%) in L and N band
    Wavelength coverage L, M and N band
    Spectral Resolution 20< R <1000 in L band, 20 < R <550 in M band and 20 < R < 250 in N band
    Field of View n/a
    Spatial Sampling n/a
    Interferometric Contrast 0.6 (goal 0.75) in L and N band
    Observing modes High Sensitivity (HighSens) and Simultaneous Photometry (SiPhot)

    See the full article here .

    Please help promote STEM in your local schools.

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    CNRS encourages collaboration between specialists from different disciplines in particular with the university thus opening up new fields of enquiry to meet social and economic needs. CNRS has developed interdisciplinary programs which bring together various CNRS departments as well as other research institutions and industry.

    Interdisciplinary research is undertaken in the following domains:

    Life and its social implications
    Information, communication and knowledge
    Environment, energy and sustainable development
    Nanosciences, nanotechnologies, materials
    Astroparticles: from particles to the Universe

     
  • richardmitnick 10:20 am on July 17, 2017 Permalink | Reply
    Tags: , , , , ESO VLT, ESO/NACO on VLT, Milky Way could have 100 billion brown dwarfs, NGC 1333, , RCW 38   

    From RAS via ESO: “Milky Way could have 100 billion brown dwarfs” 

    Royal Astronomical Society

    Royal Astronomical Society

    05 July 2017
    Media contacts
    NAM press office (Monday 3 – Thursday 6 July)
    Tel: +44 (0)1482 467507 / (0)1482 467508

    Robert Massey
    Royal Astronomical Society
    Mob: +44 (0)7802 877699
    rm@ras.org.uk

    Anita Heward
    Royal Astronomical Society
    Mob: +44 (0)7756 034243
    anitaheward@btinternet.com

    Morgan Hollis
    Royal Astronomical Society
    mh@ras.org.uk

    Science contacts

    Aleks Scholz
    University of St Andrews
    Mob: +44 (0)7399 682839

    1
    False-colour near-infrared image of the core of the young massive cluster RCW 38 taken with the adaptive-optics camera NACO at the ESO’s Very Large Telescope. RCW 38 lies at a distance of about 5500 light years from the Sun. The field of view of the central image is approximately 1 arc minute, or 1.5 light years across. The insets, each spanning about 0.07 light years on a side, show a subset of the faintest and least massive cluster candidate brown dwarfs (indicated by arrows) of RCW 38 discovered in this new image. These candidate brown dwarfs might weigh only a few tens of Jupiter masses, or about 100 times less than the most massive stars seen towards the centre of the image.

    Credit: Koraljka Muzic, University of Lisbon, Portugal / Aleks Scholz, University of St Andrews, UK / Rainer Schoedel, University of Granada, Spain / Vincent Geers, UKATC / Ray Jayawardhana, York University, Canada / Joana Ascenso, University of Lisbon, University of Porto, Portugal / Lucas Cieza, University Diego Portales, Santiago, Chile. The study is based on observations conducted with the VLT at the European Southern Observatory.

    ESO/NACO

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

    RCW 38 lies at a distance of about 5500 light years from the Sun. The field of view of the central image is approximately 1 arc minute, or 1.5 light years across. The insets, each spanning about 0.07 light years on a side, show a subset of the faintest and least massive cluster candidate brown dwarfs (indicated by arrows) of RCW 38 discovered in this new image. These candidate brown dwarfs might weigh only a few tens of Jupiter masses, or about 100 times less than the most massive stars seen towards the centre of the image. Credit: Koraljka Muzic, University of Lisbon, Portugal / Aleks Scholz, University of St Andrews, UK / Rainer Schoedel, University of Granada, Spain / Vincent Geers, UKATC / Ray Jayawardhana, York University, Canada / Joana Ascenso, University of Lisbon, University of Porto, Portugal / Lucas Cieza, University Diego Portales, Santiago, Chile. The study is based on observations conducted with the VLT at the European Southern Observatory.

    Our galaxy could have 100 billion brown dwarfs or more, according to work by an international team of astronomers, led by Koraljka Muzic from the University of Lisbon and Aleks Scholz from the University of St Andrews. On Thursday 6 July Scholz will present their survey of dense star clusters, where brown dwarfs are abundant, at the National Astronomy Meeting at the University of Hull.

    Brown dwarfs are objects intermediate in mass between stars and planets, with masses too low to sustain stable hydrogen fusion in their core, the hallmark of stars like the Sun. After the initial discovery of brown dwarfs in 1995, scientists quickly realised that they are a natural by-product of processes that primarily lead to the formation of stars and planets.

    All of the thousands of brown dwarfs found so far are relatively close to the Sun, the overwhelming majority within 1500 light years, simply because these objects are faint and therefore difficult to observe. Most of those detected are located in nearby star forming regions, which are all fairly small and have a low density of stars.

    In 2006 the team began a new search for brown dwarfs, observing five nearby star forming regions. The Substellar Objects in Nearby Young Clusters (SONYC) survey included the star cluster NGC 1333, 1000 light years away in the constellation of Perseus. That object had about half as many brown dwarfs as stars, a higher proportion than seen before.

    To establish whether NGC 1333 was unusual, in 2016 the team turned to another more distant star cluster, RCW 38, in the constellation of Vela. This has a high density of more massive stars, and very different conditions to other clusters.

    RCW 38 is 5500 light years away, meaning that the brown dwarfs are both faint, and hard to pick out next to the brighter stars. To get a clear image, Scholz, Muzic and their collaborators used the NACO adaptive optics camera on the European Southern Observatory’s Very Large Telescope, observing the cluster for a total of almost 3 hours, and combining this with earlier work.

    2
    An artist’s impression of a T-type brown dwarf. Credit: NASA / JPL-Caltech.

    The researchers found just as many brown dwarfs in RCW 38 – about half as many as there are stars- and realised that the environment where the stars form, whether stars are more or less massive, tightly packed or less crowded, has only a small effect on how brown dwarfs form.

    Scholz says: “We’ve found a lot of brown dwarfs in these clusters. And whatever the cluster type, the brown dwarfs are really common. Brown dwarfs form alongside stars in clusters, so our work suggests there are a huge number of brown dwarfs out there.”

    From the SONYC survey, Scholz and Muzic estimate that our galaxy, the Milky Way, has a minimum of between 25 and 100 billion brown dwarfs. There are many smaller, fainter brown dwarfs too, so this could be a significant underestimate, and the survey confirms these dim objects are ubiquitous.

    See the full article here .

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  • richardmitnick 10:22 am on July 5, 2017 Permalink | Reply
    Tags: , , , , ESO VLT, Messier 77   

    From ESO: “Dazzling Spiral with an Active Heart” 

    ESO 50 Large

    European Southern Observatory

    5 July 2017
    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’s Very Large Telescope (VLT) has captured a magnificent face-on view of the barred spiral galaxy Messier 77. The image does justice to the galaxy’s beauty, showcasing its glittering arms criss-crossed with dust lanes — but it fails to betray Messier 77’s turbulent nature.

    This picturesque spiral galaxy appears to be tranquil, but there is more to it than meets the eye. Messier 77 (also known as NGC 1068) is one of the closest active galaxies, which are some of the most energetic and spectacular objects in the Universe. Their nuclei are often bright enough to outshine the whole of the rest of the galaxy. Active galaxies are among the brightest objects in the Universe and emit light at most, if not all, wavelengths, from gamma rays and X-rays all the way to microwaves and radiowaves. Messier 77 is further classified as a Type II Seyfert galaxy, characterised by being particularly bright at infrared wavelengths.

    This impressive luminosity is caused by intense radiation blasting out from a central engine — the accretion disc surrounding a supermassive black hole. Material that falls towards the black hole is compressed and heated up to incredible temperatures, causing it to radiate a tremendous amount of energy. This accretion disc is thought to be enshrouded by thick doughnut-shaped structure of gas and dust, called a “torus”. Observations of Messier 77 back in 2003 were the first to resolve such a structure using the powerful VLT Interferometer (eso0319).

    This image of Messier 77 was taken in four different wavelength bands represented by blue, red, violet and pink (hydrogen-alpha) colours. Each wavelength brings out a different quality: for example, the pinkish hydrogen-alpha highlights the hotter and younger stars forming in the spiral arms, while in red are the fine, thread-like filamentary structures in the gas surrounding Messier 77 [1]. A foreground Milky Way star is also seen beside the galaxy centre, displaying tell-tale diffraction spikes. Additionally, many more distant galaxies are visible; sitting at the outskirts of the spiral arms, they appear tiny and delicate compared to the colossal active galaxy .

    Located 47 million light-years away in the constellation of Cetus (The Sea Monster), Messier 77 is one of the most remote galaxies of the Messier catalogue. Initially, Messier believed that the highly luminous object he saw through his telescope was a cluster of stars, but as technology progressed its true status as a galaxy was realised. At approximately 100 000 light-years across, Messier 77 is also one of largest galaxies in the Messier catalogue — so massive that its gravity causes other nearby galaxies to twist and become warped (eso1707) [2].

    This image was obtained using the FOcal Reducer and low dispersion Spectrograph 2 (FORS2) instrument mounted on Unit Telescope 1 (Antu) of the VLT, located at ESO’s Paranal Observatory in Chile.

    ESO FORS2 VLT

    It hails from ESO’s Cosmic Gems programme, an outreach initiative that produces images of interesting, intriguing or visually attractive objects using ESO telescopes for the purposes of education and outreach.

    Notes

    [1] Similar red filaments are also found in NGC 1275.

    3
    This stunning image of NGC 1275 was taken using the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys in July and August 2006. It provides amazing detail and resolution of the fragile filamentary structures, which show up as a reddish lacy structure surrounding the central bright galaxy NGC 1275. These filaments are cool despite being surrounded by gas that is around 55 million degrees Celsius hot. They are suspended in a magnetic field which maintains their structure and demonstrates how energy from the central black hole is transferred to the surrounding gas.

    NASA/ESA Hubble Telescope

    NASA/ESA Hubble ACS

    They are cool, despite being surrounded by a very hot gas at around 50 million degrees Celsius. The filaments are suspended in a magnetic field which maintains their structure and demonstrates how energy from the central black hole is transferred to the surrounding gas.

    [2] NGC 1055 is located about 60 million light-years away.

    4
    This colourful image from ESO’s Very Large Telescope shows NGC 1055 in the constellation of Cetus (The Sea Monster). This large galaxy is thought to be up to 15 percent larger in diameter than the Milky Way. NGC 1055 appears to lack the whirling arms characteristic of a spiral, as it is seen edge-on. However, it displays odd twists in its structure that were probably caused by an interaction with a large neighbouring galaxy.

    It is an edge-on galaxy, in contrast to Messier 77. This Astronomy Picture of the Day portrays both of them together, in a field of view about the size of the Moon (APOD).

    5
    Cetus Duo M77 and NGC 1055
    Image Credit & Copyright: Dieter Willasch (Astro-Cabinet)

    At the top right, large spiral galaxy NGC 1055 joins spiral Messier 77 in this sharp cosmic view toward the aquatic constellation Cetus. The narrowed, dusty appearance of edge-on spiral NGC 1055 contrasts nicely with the face-on view of Messier 77’s bright nucleus and spiral arms. Both over 100,000 light-years across, the pair are dominant members of a small galaxy group about 60 million light-years away. At that estimated distance, M77 is one of the most remote objects in Charles Messier’s catalog and is separated from fellow island universe NGC 1055 by at least 500,000 light-years. The field of view is about the size of the full Moon on the sky and includes colorful foreground Milky Way stars (with diffraction spikes) along with more distant background galaxies.

    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

     
  • richardmitnick 9:48 am on May 21, 2017 Permalink | Reply
    Tags: , , , , , ESO VLT,   

    From Manu Garcia: “M83, Messier 83, a barred spiral galaxy” 


    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.

    1
    The galaxy Messier 83 is located about 15 million away in the constellation Hydra light-years. Its extension reaches more than 40 thousand light-years, only 40 percent of the size of the Milky Way, but in many ways is similar to our home galaxy, both in its spiral shape and the presence of a band of stars that crosses its center. Messier 83 is famous among astronomers for its many supernovae: vast explosions that killed some stars. In the past century , six supernovae were observed in Messier 83 , a record number has been reached only by a galaxy. Even without supernovae, Messier 83 is one of the brightest nearby galaxies that can be seen using binoculars.

    ESO unveiled one of the most accurate and detailed portraits obtained so far from the nearby galaxy Messier 83. The image, taken with the instrument HAWK-I’s Very Large Telescope (VLT) at the Paranal Observatory (Chile) , shows the galaxy in infrared light and demonstrates the incredible power of this camera.

    ESO HAWK-I

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

    The combination of the huge mirror of the VLT , the large field of view and sensitivity of the camera, and the superb observing conditions of Paranal Observatory ESO , makes HAWK-I one of the most powerful cameras in the world in near infrared. Astronomers eagerly await their turn to use this camera, which began operations in 2007, and to obtain some of the best infrared images taken from Earth to the night sky.

    notes
    [1] HAWK-I stands for High-Acuity Wide-field K-band Imager or high acuity camera, wide – field band K.

    [2] The data used to prepare this were assembled by a team led by Mark Gieles (Cambridge University) and Yuri Beletsky (ESO). Mirna Schirmer (University of Bonn) performed the complex data processing.

    See the full article here .

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  • richardmitnick 10:24 am on March 27, 2017 Permalink | Reply
    Tags: , , , , , ESO VLT, ESO X-shooter, IRAS F23128-5919, Stars Born in Winds from Supermassive Black Holes   

    From ESO: “Stars Born in Winds from Supermassive Black Holes” 

    ESO 50 Large

    European Southern Observatory

    27 March 2017
    Roberto Maiolino
    Cavendish Laboratory, Kavli Institute for Cosmology
    University of Cambridge, UK
    Email: r.maiolino@mrao.cam.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

    1
    Observations using ESO’s Very Large Telescope have revealed stars forming within powerful outflows of material blasted out from supermassive black holes at the cores of galaxies. These are the first confirmed observations of stars forming in this kind of extreme environment. The discovery has many consequences for understanding galaxy properties and evolution. The results are published in the journal Nature.

    A UK-led group of European astronomers used the MUSE and X-shooter instruments on the Very Large Telescope (VLT) at ESO’s Paranal Observatory in Chile to study an ongoing collision between two galaxies, known collectively as IRAS F23128-5919, that lie around 600 million light-years from Earth. The group observed the colossal winds of material — or outflows — that originate near the supermassive black hole at the heart of the pair’s southern galaxy, and have found the first clear evidence that stars are being born within them [1].

    2
    IRAS F23128-5919 https://inspirehep.net/record/1265769/plots


    ESO/MUSE on VLT


    ESO X-shooter on VLT

    Such galactic outflows are driven by the huge energy output from the active and turbulent centres of galaxies. Supermassive black holes lurk in the cores of most galaxies, and when they gobble up matter they also heat the surrounding gas and expel it from the host galaxy in powerful, dense winds [2].

    “Astronomers have thought for a while that conditions within these outflows could be right for star formation, but no one has seen it actually happening as it’s a very difficult observation,” comments team leader Roberto Maiolino from the University of Cambridge. “Our results are exciting because they show unambiguously that stars are being created inside these outflows.”

    The group set out to study stars in the outflow directly, as well as the gas that surrounds them. By using two of the world-leading VLT spectroscopic instruments, MUSE and X-shooter, they could carry out a very detailed study of the properties of the emitted light to determine its source.

    Radiation from young stars is known to cause nearby gas clouds to glow in a particular way. The extreme sensitivity of X-shooter allowed the team to rule out other possible causes of this illumination, including gas shocks or the active nucleus of the galaxy.

    The group then made an unmistakable direct detection of an infant stellar population in the outflow [3]. These stars are thought to be less than a few tens of millions of years old, and preliminary analysis suggests that they are hotter and brighter than stars formed in less extreme environments such as the galactic disc.

    As further evidence, the astronomers also determined the motion and velocity of these stars. The light from most of the region’s stars indicates that they are travelling at very large velocities away from the galaxy centre — as would make sense for objects caught in a stream of fast-moving material.

    Co-author Helen Russell (Institute of Astronomy, Cambridge, UK) expands: “The stars that form in the wind close to the galaxy centre might slow down and even start heading back inwards, but the stars that form further out in the flow experience less deceleration and can even fly off out of the galaxy altogether.”

    The discovery provides new and exciting information that could better our understanding of some astrophysics, including how certain galaxies obtain their shapes [4]; how intergalactic space becomes enriched with heavy elements [5]; and even from where unexplained cosmic infrared background radiation may arise [6].

    Maiolino is excited for the future: “If star formation is really occurring in most galactic outflows, as some theories predict, then this would provide a completely new scenario for our understanding of galaxy evolution.”
    Notes

    [1] Stars are forming in the outflows at a very rapid rate; the astronomers say that stars totalling around 30 times the mass of the Sun are being created every year. This accounts for over a quarter of the total star formation in the entire merging galaxy system.

    [2] The expulsion of gas through galactic outflows leads to a gas-poor environment within the galaxy, which could be why some galaxies cease forming new stars as they age. Although these outflows are most likely to be driven by massive central black holes, it is also possible that the winds are powered by supernovae in a starburst nucleus undergoing vigorous star formation.

    [3] This was achieved through the detection of signatures characteristic of young stellar populations and with a velocity pattern consistent with that expected from stars formed at high velocity in the outflow.

    [4] Spiral galaxies have an obvious disc structure, with a distended bulge of stars in the centre and surrounded by a diffuse cloud of stars called a halo. Elliptical galaxies are composed mostly of these spheroidal components. Outflow stars that are ejected from the main disc could give rise to these galactic features.

    [5] How the space between galaxies — the intergalactic medium — becomes enriched with heavy elements is still an open issue, but outflow stars could provide an answer. If they are jettisoned out of the galaxy and then explode as supernovae, the heavy elements they contain could be released into this medium.

    [6] Cosmic-infrared background radiation, similar to the more famous cosmic microwave background, is a faint glow in the infrared part of the spectrum that appears to come from all directions in space. Its origin in the near-infrared bands, however, has never been satisfactorily ascertained. A population of outflow stars shot out into intergalactic space may contribute to this light.
    More information

    This research was presented in a paper entitled “Star formation in a galactic outflow” by Maiolino et al., to appear in the journal Nature on 27 March 2017 [link is above with image detail].

    The team is composed of R. Maiolino (Cavendish Laboratory; Kavli Institute for Cosmology, University of Cambridge, UK), H.R. Russell (Institute of Astronomy, Cambridge, UK), A.C. Fabian (Institute of Astronomy, Cambridge, UK), S. Carniani (Cavendish Laboratory; Kavli Institute for Cosmology, University of Cambridge, UK), R. Gallagher (Cavendish Laboratory; Kavli Institute for Cosmology, University of Cambridge, UK), S. Cazzoli (Departamento de Astrofisica-Centro de Astrobiología, Madrid, Spain), S. Arribas (Departamento de Astrofisica-Centro de Astrobiología, Madrid, Spain), F. Belfiore ((Cavendish Laboratory; Kavli Institute for Cosmology, University of Cambridge, UK), E. Bellocchi (Departamento de Astrofisica-Centro de Astrobiología, Madrid, Spain), L. Colina (Departamento de Astrofisica-Centro de Astrobiología, Madrid, Spain), G. Cresci (Osservatorio Astrofisico di Arcetri, Firenze, Italy), W. Ishibashi (Universität Zürich, Zürich, Switzerland), A. Marconi (Osservatorio Astrofisico di Arcetri, Firenze, Italy), F. Mannucci (Osservatorio Astrofisico di Arcetri, Firenze, Italy), E. Oliva (Osservatorio Astrofisico di Arcetri, Firenze, Italy), and E. Sturm (Max-Planck-Institut für Extraterrestrische Physik, Garching, Germany).

    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

     
  • richardmitnick 1:44 pm on March 15, 2017 Permalink | Reply
    Tags: , , , , Dark Matter Less Influential in Galaxies in Early Universe, ESO KMOS, ESO SINFONI, ESO VLT   

    From ESO: “Dark Matter Less Influential in Galaxies in Early Universe” 

    ESO 50 Large

    European Southern Observatory

    15 March 2017
    Reinhard Genzel
    Director, Max-Planck-Institut für extraterrestrische Physik
    Garching bei München, Germany
    Tel: +49 89 30000 3280
    Email: genzel@mpe.mpg.de

    Natascha M. Forster Schreiber
    Senior Scientist, Max-Planck-Institut für extraterrestrische Physik
    Garching bei München, Germany
    Tel: +49 89 30000 3524
    Email: forster@mpe.mpg.de

    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
    Schematic representation of rotating disc galaxies in the early Universe (right) and the present day (left). Observations with ESO’s Very Large Telescope suggest that such massive star-forming disc galaxies in the early Universe were less influenced by dark matter (shown in red), as it was less concentrated. As a result the outer parts of distant galaxies rotate more slowly than comparable regions of galaxies in the local Universe. Credit: ESO/L. Calçada

    2
    Schematic representation of rotating disc galaxies in the distant Universe and the present day. Observations with ESO’s Very Large Telescope suggest that such massive star-forming disc galaxies in the early Universe were less influenced by dark matter. As a result the outer parts of distant galaxies rotate more slowly than comparable regions of galaxies in the local Universe. Their rotations curves, rather than being flat, drop with increasing radius. Credit: ESO


    Access mp4 video here .
    New observations from ESO’s Very Large Telescope have revealed that the outer parts of massive disc galaxies 10 billion years ago were rotating less quickly than the spiral galaxies, like the Milky Way, that we see today. This ESOcast Light summarises the important points of this discovery and the significance of dark matter, and how it is distributed.
    The video is available in 4K UHD.
    The ESOcast Light is a series of short videos bringing you the wonders of the Universe in bite-sized pieces. The ESOcast Light episodes will not be replacing the standard, longer ESOcasts, but complement them with current astronomy news and images in ESO press releases. Credit: ESO

    Editing: Herbert Zodet.
    Web and technical support: Mathias André and Raquel Yumi Shida.
    Written by: Thomas Barratt and Lauren Fuge.
    Music: Jennifer Athena Galatis.
    Footage and photos: ESO, The Illustris Project (visualization by Dylan Nelson), L. Calçada and F. Char.
    Directed by: Herbert Zodet.
    Executive producer: Lars Lindberg Christensen.

    New observations indicate that massive, star-forming galaxies during the peak epoch of galaxy formation, 10 billion years ago, were dominated by baryonic or “normal” matter. This is in stark contrast to present-day galaxies, where the effects of mysterious dark matter seem to be much greater. This surprising result was obtained using ESO’s Very Large Telescope and suggests that dark matter was less influential in the early Universe than it is today. The research is presented in four papers, one of which was published in the journal Nature today.

    We see normal matter as brightly shining stars, glowing gas and clouds of dust. But the more elusive dark matter does not emit, absorb or reflect light and can only be observed via its gravitational effects. The presence of dark matter can explain why the outer parts of nearby spiral galaxies rotate more quickly than would be expected if only the normal matter that we can see directly were present [1].

    Now, an international team of astronomers led by Reinhard Genzel at the Max Planck Institute for Extraterrestrial Physics in Garching, Germany have used the KMOS and SINFONI instruments at ESO’s Very Large Telescope in Chile [2] to measure the rotation of six massive, star-forming galaxies in the distant Universe, at the peak of galaxy formation 10 billion years ago.


    KMOS


    SINFONI

    What they found was intriguing: unlike spiral galaxies in the modern Universe, the outer regions of these distant galaxies seem to be rotating more slowly than regions closer to the core — suggesting there is less dark matter present than expected [3].

    “Surprisingly, the rotation velocities are not constant, but decrease further out in the galaxies,” comments Reinhard Genzel, lead author of the Nature paper. “There are probably two causes for this. Firstly, most of these early massive galaxies are strongly dominated by normal matter, with dark matter playing a much smaller role than in the Local Universe. Secondly, these early discs were much more turbulent than the spiral galaxies we see in our cosmic neighbourhood.”

    Both effects seem to become more marked as astronomers look further and further back in time, into the early Universe. This suggests that 3 to 4 billion years after the Big Bang, the gas in galaxies had already efficiently condensed into flat, rotating discs, while the dark matter halos surrounding them were much larger and more spread out. Apparently it took billions of years longer for dark matter to condense as well, so its dominating effect is only seen on the rotation velocities of galaxy discs today

    This explanation is consistent with observations showing that early galaxies were much more gas-rich and compact than today’s galaxies.

    The six galaxies mapped in this study were among a larger sample of a hundred distant, star-forming discs imaged with the KMOS and SINFONI instruments at ESO’s Very Large Telescope at the Paranal Observatory in Chile. In addition to the individual galaxy measurements described above, an average rotation curve was created by combining the weaker signals from the other galaxies. This composite curve also showed the same decreasing velocity trend away from the centres of the galaxies. In addition, two further studies of 240 star forming discs also support these findings.

    Detailed modelling shows that while normal matter typically accounts for about half of the total mass of all galaxies on average, it completely dominates the dynamics of galaxies at the highest redshifts.
    Notes

    [1] The disc of a spiral galaxy rotates over a timescale of hundreds of millions of years. Spiral galaxy cores have high concentrations of stars, but the density of bright matter decreases towards their outskirts. If a galaxy’s mass consisted entirely of normal matter, then the sparser outer regions should rotate more slowly than the dense regions at the centre. But observations of nearby spiral galaxies show that their inner and outer parts actually rotate at approximately the same speed. These “flat rotation curves ” indicate that spiral galaxies must contain large amounts of non-luminous matter in a dark matter halo surrounding the galactic disc.

    [2] The data analysed were obtained with the integral field spectrometers KMOS and SINFONI at ESO’s Very Large Telescope in Chile in the framework of the KMOS3D and SINS/zC-SINF surveys. It is the first time that such a comprehensive study of the dynamics of a large number of galaxies spanning the redshift interval from z~0.6 to 2.6, or 5 billion years of cosmic time, has been carried out.

    [3] This new result does not call into question the need for dark matter as a fundamental component of the Universe or the total amount. Rather it suggests that dark matter was differently distributed in and around disc galaxies at early times compared to the present day.
    More information

    This research was presented in a paper entitled Strongly baryon dominated disk galaxies at the peak of galaxy formation ten billion years ago, by R. Genzel et al., to appear in the journal Nature.

    The team is composed of R. Genzel (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany; University of California, Berkeley, USA), N.M. Förster Schreiber (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), H. Übler (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), P. Lang (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), T. Naab (Max-Planck-Institut für Astrophysik, Garching, Germany), R. Bender (Universitäts-Sternwarte Ludwig-Maximilians-Universität, München, Germany; Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), L.J. Tacconi (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), E. Wisnioski (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), S.Wuyts (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany; University of Bath, Bath, UK), T. Alexander (The Weizmann Institute of Science, Rehovot, Israel), A. Beifiori (Universitäts-Sternwarte Ludwig-Maximilians-Universität, München, Germany; Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), S.Belli (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), G. Brammer (Space Telescope Science Institute, Baltimore, USA), A.Burkert (Max-Planck-Institut für Astrophysik, Garching, Germany; Max-Planck-Institut für extraterrestrische Physik, Garching, Germany) C.M. Carollo (Eidgenössische Technische Hochschule, Zürich, Switzerland), J. Chan (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), R. Davies (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), M. Fossati (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany; Universitäts-Sternwarte Ludwig-Maximilians-Universität, München, Germany), A. Galametz (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany; Universitäts-Sternwarte Ludwig-Maximilians-Universität, München, Germany), S. Genel (Center for Computational Astrophysics, New York, USA), O. Gerhard (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), D. Lutz (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), J.T. Mendel (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany; Universitäts-Sternwarte Ludwig-Maximilians-Universität, München, Germany), I. Momcheva (Yale University, New Haven, USA), E.J. Nelson (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany; Yale University, New Haven, USA), A. Renzini (Vicolo dell’Osservatorio 5, Padova, Italy), R.Saglia (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany; Universitäts-Sternwarte Ludwig-Maximilians-Universität, München, Germany), A. Sternberg (Tel Aviv University, Tel Aviv, Israel), S. Tacchella (Eidgenössische Technische Hochschule, Zürich, Switzerland), K.Tadaki (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany) and D. Wilman (Universitäts-Sternwarte Ludwig-Maximilians-Universität, München, Germany; Max-Planck-Institut für extraterrestrische Physik, Garching, Germany)

    Links

    Research Paper 1
    Research Paper 2
    Research Paper 3
    Research Paper 4

    See the full article here .

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    • gregoriobaquero 7:26 pm on March 15, 2017 Permalink | Reply

      The younger the galaxy (the farther away we look) the less DM. It is an accumulative phenomenon.

      Like

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