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  • richardmitnick 11:55 am on October 10, 2019 Permalink | Reply
    Tags: "The Milky Way kidnapped several tiny galaxies from its neighbor", , , , , Large Magellanic Cloud,   

    From UC Riverside: “The Milky Way kidnapped several tiny galaxies from its neighbor” 

    UC Riverside bloc

    From UC Riverside

    October 10, 2019
    Iqbal Pittalwala

    UC Riverside-led research shows our galaxy is undergoing a massive merger with its largest satellite galaxy, the Large Magellanic Cloud.

    Large Magellanic Cloud. Adrian Pingstone December 2003

    Just like the moon orbits the Earth, and the Earth orbits the sun, galaxies orbit each other according to the predictions of cosmology.

    For example, more than 50 discovered satellite galaxies orbit our own galaxy, the Milky Way. The largest of these is the Large Magellanic Cloud, or LMC, a large dwarf galaxy that resembles a faint cloud in the Southern Hemisphere night sky.

    A team of astronomers led by scientists at the University of California, Riverside, has discovered that several of the small — or “dwarf” — galaxies orbiting the Milky Way were likely stolen from the LMC, including several ultrafaint dwarfs, but also relatively bright and well-known satellite galaxies, such as Carina and Fornax.

    The researchers made the discovery by using new data gathered by the Gaia space telescope on the motions of several nearby galaxies and contrasting this with state-of-the-art cosmological hydrodynamical simulations.

    ESA/GAIA satellite

    The UC Riverside team used the positions in the sky and the predicted velocities of material, such as dark matter, accompanying the LMC, finding that at least four ultrafaint dwarfs and two classical dwarfs, Carina and Fornax, used to be satellites of the LMC. Through the ongoing merger process, however, the more massive Milky Way used its powerful gravitational field to tear apart the LMC and steal these satellites, the researchers report.

    “These results are an important confirmation of our cosmological models, which predict that small dwarf galaxies in the universe should also be surrounded by a population of smaller fainter galaxy companions,” said Laura Sales, an assistant professor of physics and astronomy, who led the research team. “This is the first time that we are able to map the hierarchy of structure formation to such faint and ultrafaint dwarfs.”

    2
    Laura Sales (right), an assistant professor of physics and astronomy at UC Riverside, is seen here with Ethan Jahn, her graduate student. (UCR/Sales group)

    The findings have important implications for the total mass of the LMC and also on the formation of the Milky Way.

    “If so many dwarfs came along with the LMC only recently, that means the properties of the Milky Way satellite population just 1 billion years ago were radically different, impacting our understanding of how the faintest galaxies form and evolve,” Sales said.

    Study results appear in the November 2019 issue of the Monthly Notices of the Royal Astronomical Society.

    Dwarf galaxies are small galaxies that contain anywhere from a few thousand to a few billion stars. The researchers used computer simulations from the Feedback In Realistic Environments project to show the LMC and galaxies similar to it host numerous tiny dwarf galaxies, many of which contain no stars at all — only dark matter, a type of matter scientists think constitutes the bulk of the universe’s mass.

    3
    Visualization of the simulations used in the study. Top left shows dark matter in white. Bottom right shows a simulated Large Magellanic Cloud-like galaxy with stars and gas, and several smaller companion galaxies. (UCR/Ethan Jahn)

    “The high number of tiny dwarf galaxies seems to suggest the dark matter content of the LMC is quite large, meaning the Milky Way is undergoing the most massive merger in its history, with the LMC, its partner, bringing in as much as one third of the mass in the Milky Way’s dark matter halo — the halo of invisible material that surrounds our galaxy,” said Ethan Jahn, the first author of the paper and a graduate student in Sales’ research group.

    Jahn explained that the number of tiny dwarf galaxies the LMC hosts may be higher than astronomers previously estimated, and that many of these tiny satellites have no stars.

    “Small galaxies are hard to measure, and it’s possible that some already-known ultrafaint dwarf galaxies are in fact associated with the LMC,” he said. “It’s also possible that we will discover new ultrafaints that are associated with the LMC.”

    Dwarf galaxies can either be satellites of larger galaxies, or they can be “isolated,” existing on their own and independent of any larger object. The LMC used to be isolated, Jahn explained, but it was captured by the gravity of the Milky Way and is now its satellite.

    “The LMC hosted at least seven satellite galaxies of its own, including the Small Magellanic Cloud in the Southern Sky, prior to them being captured by the Milky Way,” he said.

    Next, the team will study how the satellites of LMC-sized galaxies form their stars and how that relates to how much dark matter mass they have.

    “It will be interesting to see if they form differently than satellites of Milky Way-like galaxies,” Jahn said.

    Sales and Jahn were joined in the study Andrew Wetzel of UC Davis; Michael Boylan-Kolchin of the University of Texas at Austin; T. K. Chan of UC San Diego; Kareem El-Badry of UC Berkeley; and Alexandres Lazar and James S. Bullock of UC Irvine.

    The research was supported by grants to Sales from NASA and the Hellman Foundation.

    See the full article here .

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    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 11:17 am on February 6, 2019 Permalink | Reply
    Tags: Adaptive Optics-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, , , , , , , Herbig–Haro 1177 or HH 1177 for short, In HII region LHA 120-N 180B MUSE has spotted a jet emitted by a fledgling star — a massive young stellar object . This is the first time such a jet has been observed in visible light outside the Mi, Large Magellanic Cloud, N180 B   

    From European Southern Observatory: “Bubbles of Brand New Stars” 

    From European Southern Observatory

    6 February 2019

    Anna McLeod
    Postdoctoral Research Fellow — Texas Tech University & University of California Berkeley
    Tel: +1 80 6834 2588
    Email: anna.mcleod@ttu.edu

    Calum Turner
    ESO Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6670
    Email: pio@eso.org

    1
    This dazzling region of newly-forming stars in the Large Magellanic Cloud (LMC) was captured by the Multi Unit Spectroscopic Explorer instrument (MUSE) on ESO’s Very Large Telescope [see below]. The relatively small amount of dust in the LMC and MUSE’s acute vision allowed intricate details of the region to be picked out in visible light.

    ESO MUSE on the VLT on Yepun (UT4)

    2
    Deep within the glowing cloud of the HII region LHA 120-N 180B, MUSE has spotted a jet emitted by a fledgling star — a massive young stellar object . This is the first time such a jet has been observed in visible light outside the Milky Way. Usually, such jets are obscured by their dusty surroundings, meaning they can only be detected at infrared or radio wavelengths by telescopes such as ALMA [see below]. However, the relatively dust-free environment of the LMC allowed this jet — named Herbig–Haro 1177, or HH 1177 for short — to be observed at visible wavelengths. At nearly 33 light-years in length, it is one of the longest such jets ever observed. The blue and red regions in this image show the jet, which was detected as blue- and red-shifted emission peaks of the Hα line. Credit: ESO, A McLeod et al.

    3
    This dazzling region of newly-forming stars in the Large Magellanic Cloud (LMC) was captured by the Multi Unit Spectroscopic Explorer instrument on ESO’s Very Large Telescope [see below]. The relatively small amount of dust in the LMC and MUSE’s acute vision allowed intricate details of the region to be picked out in visible light.
    The image is a colour composite made from exposures from the Digitized Sky Survey 2 [produced by the Space Telescope Science Institute between 1983 and 2006}, and shows the region surrounding LHA 120-N 180B, visible at the centre of the image. Credit: ESO/Digitized Sky Survey 2. Acknowledgment: Davide De Martin

    Jet Infographic
    4
    Credit: ESO, A McLeod et al.

    See the full article to access three videos on this work.

    This region of the Large Magellanic Cloud (LMC) glows in striking colours in this image captured by the Multi Unit Spectroscopic Explorer (MUSE) instrument on ESO’s Very Large Telescope (VLT). The region, known as LHA 120-N 180B — N180 B for short — is a type of nebula known as an H II region (pronounced “H two”), and is a fertile source of new stars.

    The LMC is a satellite galaxy of the Milky Way, visible mainly from the Southern Hemisphere.

    Large Magellanic Cloud. Adrian Pingstone December 2003

    Large Magellanic Cloud by by German astrophotographer Eckhard Slawik

    At only around 160 000 light-years away from the Earth, it is practically on our doorstep. As well as being close to home, the LMC’s single spiral arm appears nearly face-on, allowing us to inspect regions such as N180 B with ease.

    Large Magellanic Cloud by Carlos Milovic showing spiral arms

    H II regions are interstellar clouds of ionised hydrogen — the bare nuclei of hydrogen atoms. These regions are stellar nurseries — and the newly formed massive stars are responsible for the ionisation of the surrounding gas, which makes for a spectacular sight. N180 B’s distinctive shape is made up of a gargantuan bubble of ionised hydrogen surrounded by four smaller bubbles.

    HH 1177 tells us about the early lives of stars. The beam is highly collimated; it barely spreads out as it travels. Jets like this are associated with the accretion discs of their star, and can shed light on how fledgling stars gather matter. Astronomers have found that both high- and low-mass stars launch collimated jets like HH 1177 via similar mechanisms — hinting that massive stars can form in the same way as their low-mass counterparts.

    MUSE has recently been vastly improved by the addition of the Adaptive Optics Facility , the Wide Field Mode of which saw first light in 2017. Adaptive optics is the process by which ESO’s telescopes compensate for the blurring effects of the atmosphere — turning twinkling stars into sharp, high-resolution images. Since obtaining these data, the addition of the Narrow Field Mode, has given MUSE vision nearly as sharp as that of the NASA/ESA Hubble Space Telescope — giving it the potential to explore the Universe in greater detail than ever before.

    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.

    More information

    This research was presented in a paper entitled “An optical parsec-scale jet from a massive young star in the Large Magellanic Cloud” which appeared in the journal Nature.

    The research team was composed of A. F. McLeod (who conducted this research while at the University of Canterbury, New Zealand and is now affiliated with the Department of Astronomy, University of California, Berkeley, and the Department of Physics and Astronomy, Texas Tech University, USA), M. Reiter (Department of Astronomy, University of Michigan, Ann Arbor, USA), R. Kuiper (Institute of Astronomy and Astrophysics, University of Tübingen, Germany), P. D. Klaassen (UK Astronomy Technology Centre, Royal Observatory Edinburgh, UK) and C. J, Evans (UK Astronomy Technology Centre, Royal Observatory Edinburgh, UK).

    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 EEuropean Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

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    ESO VLT 4 lasers on Yepun

    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

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

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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

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    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 1:47 pm on January 4, 2019 Permalink | Reply
    Tags: , , , , Large Magellanic Cloud, , The Large Magellanic Cloud could hit our galaxy in two billion years’ time., The Milky Way is on a collision course with a neighbouring galaxy that could fling our Solar System into space   

    From Durham University: “Milky Way heading for catastrophic collision” 

    Durham U bloc

    From Durham University

    4 January 2019

    1
    Hubble Space Telescope image representing a merger between two galaxies (M51a and M51b) similar in mass to the Milky Way and the Large Magellanic Cloud. Credit: NASA, ESA, S. Beckwith (STScI), and The Hubble Heritage Team (STScI/AURA)

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

    Large Magellanic Cloud by by German astrophotographer Eckhard Slawik

    There’s an enemy in our midst. Quietly circling around our galaxy, it could send our Solar System hurtling out of the Milky Way and into the obscurity of interstellar space.

    Its name is the Large Magellanic Cloud (LMC), and even though it is one of the more researched satellite galaxies buzzing around our own, astrophysicists are only now seeing it for what it truly is: an unusually large cosmic threat.

    The Milky Way is on a collision course with a neighbouring galaxy that could fling our Solar System into space.

    The Large Magellanic Cloud could hit our galaxy in two billion years’ time.

    On the off chance that humans survive for another two billion years, our descendants will be in for a treat.

    If the catastrophic collision wakes up the black hole sleeping at the center of our galaxy, this dark beast will begin devouring everything in sight, growing ten times larger than it already is.

    As it feeds on surrounding gas, the stage will be set and the show will begin – what the researchers describe as a “spectacular display of cosmic fireworks.”

    “This phenomenon will generate powerful jets of high energy radiation emanating from just outside the black hole,” explains lead author Marius Cautun, a cosmologist at Durham University.

    “While this will not affect our Solar System, there is a small chance that we might not escape unscathed from the collision between the two galaxies which could knock us out of the Milky Way and into interstellar space.”

    Our galaxy is long overdue for such a collision. So far, it has managed to get by relatively unscathed in the grand scheme of things. Especially when you consider the company that it keeps.

    The Milky Way is surrounded by a group of smaller satellite galaxies, orbiting quietly around us.

    These galaxies can lead separate lives for many billions of years, but on occasion, they can find themselves sinking into the centre of their host galaxy, until at last they collide and are swallowed up completely.

    In this way, galaxies are constantly evolving and growing, but the Milky Way’s poor appetite makes it quite atypical.

    In comparison to our own galaxy, for instance, Andromeda can devour galaxies weighing nearly 30 times more.

    “We think that up to now our galaxy has had only a few mergers with very low mass galaxies,” says co-author Alis Deason, a computational cosmologist at Durham University.

    “This represents very slim pickings when compared to nearby galaxies of the same size as the Milky Way.”

    This galactic collision would happen much sooner than the predicted impact between the Milky Way and another neighbour, Andromeda, which scientists say will hit our galaxy in eight billion years.

    Andromeda Galaxy Adam Evans

    Active black hole

    The coming together with the Large Magellanic Cloud could wake up our galaxy’s dormant black hole, which would begin devouring surrounding gas and increase in size by up to ten times.

    SGR A* , the supermassive black hole at the center of the Milky Way. NASA’s Chandra X-Ray Observatory

    Sgr A* from ESO VLT

    As it feeds, the now-active black hole would throw out high-energy radiation.

    While these cosmic fireworks are unlikely to affect life on Earth, researchers say there is a small chance that the initial collision could send our Solar System hurtling into space.

    Dark matter

    The Large Magellanic Cloud is the Milky Way’s brightest satellite galaxy and only entered our neighbourhood about 1.5 billion years ago. It sits about 163,000 light years from our galaxy.

    Until recently, astronomers thought that it would either orbit the Milky Way for many billions of years, or, since it moves so fast, escape from our galaxy’s gravitational pull.

    However, recent measurements indicate that the Large Magellanic Cloud has nearly twice as much dark matter than previously thought.

    Solar System

    Researchers say that since it has a larger than expected mass, the Large Magellanic Cloud is rapidly losing energy and is doomed to collide with our galaxy, which could have consequences for our Solar System.

    Lead researcher Dr Marius Cautun, a postdoctoral fellow in our Institute for Computational Cosmology, said: “There is a small chance that we might not escape unscathed from the collision between the two galaxies, which could knock us out of the Milky Way and into space.”

    Read the full research paper MNRAS.

    See the full article here .

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    Durham University is distinctive – a residential collegiate university with long traditions and modern values. We seek the highest distinction in research and scholarship and are committed to excellence in all aspects of education and transmission of knowledge. Our research and scholarship affect every continent. We are proud to be an international scholarly community which reflects the ambitions of cultures from around the world. We promote individual participation, providing a rounded education in which students, staff and alumni gain both the academic and the personal skills required to flourish.

     
  • richardmitnick 1:05 pm on May 11, 2018 Permalink | Reply
    Tags: , , Australia Telescope Compact Array at the Paul Wild Observatory in New South Wales Australia, , , Large Magellanic Cloud, , , ,   

    From University of Toronto Dunlap Institute for Astronomy: “Mapping the Magnetic Bridge Between Our Nearest Galactic Neighbours” May 11 2017 

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    From University of Toronto

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    Dunlap Institute for Astronomy and Astrophysics

    May 11 2017 [just now in social media.]

    Jane Kaczmarek
    School of Physics
    University of Sydney
    e: jane.kaczmarek@sydney.edu.au

    Prof. Bryan Gaensler, Director
    Dunlap Institute for Astronomy & Astrophysics
    University of Toronto
    p: 416-978-6623
    e: bgaensler@dunlap.utoronto.ca
    w: dunlap.utoronto.ca

    Chris Sasaki
    Communications Co-ordinator
    Dunlap Institute for Astronomy & Astrophysics
    University of Toronto
    p: 416-978-6613
    e: csasaki@dunlap.utoronto.ca
    w: dunlap.utoronto.ca

    For the first time, astronomers have detected a magnetic field associated with the Magellanic Bridge, the filament of gas stretching 75 thousand light-years between the Milky Way Galaxy’s nearest galactic neighbours: the Large and Small Magellanic Clouds (LMC and SMC, respectively).

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

    ESA/GAIA satellite

    2
    The Large (centre left) and Small (centre right) Magellanic Clouds are seen in the sky above a radio telescope that is part of the Australia Telescope Compact Array at the Paul Wild Observatory in New South Wales, Australia. Image: Mike Salway

    CSIRO ATCA at the Paul Wild Observatory, about 25 km west of the town of Narrabri in rural NSW about 500 km north-west of Sydney, AU

    Visible in the southern night sky, the LMC and SMC are dwarf galaxies that orbit our home galaxy and lie at a distance of 160 and 200 thousand light-years from Earth respectively.

    Small Magellanic Cloud. NASA/ESA Hubble and ESO/Digitized Sky Survey 2

    Large Magellanic Cloud. Adrian Pingstone December 2003

    “There were hints that this magnetic field might exist, but no one had observed it until now,” says Jane Kaczmarek, a PhD student in the School of Physics, University of Sydney, and lead author of the paper describing the finding.

    Such cosmic magnetic fields can only be detected indirectly, and this detection was made by observing the radio signals from hundreds of very distant galaxies that lie beyond the LMC and SMC. The observations were made with the Australia Telescope Compact Array radio telescope at the Paul Wild Observatory in New South Wales, Australia.

    “The radio emission from the distant galaxies served as background ‘flashlights’ that shine through the Bridge,” says Kaczmarek. “Its magnetic field then changes the polarization of the radio signal. How the polarized light is changed tells us about the intervening magnetic field.”

    A radio signal, like a light wave, oscillates or vibrates in a single direction or plane; for example, waves on the surface of a pond move up and down. When a radio signal passes through a magnetic field, the plane is rotated. This phenomenon is known as Faraday Rotation and it allows astronomers to measure the strength and the polarity—or direction—of the field.

    The observation of the magnetic field, which is one millionth the strength of the Earth’s, may provide insight into whether it was generated from within the Bridge after the structure formed, or was “ripped” from the dwarf galaxies when they interacted and formed the structure.

    “In general, we don’t know how such vast magnetic fields are generated, nor how these large-scale magnetic fields affect galaxy formation and evolution,” says Kaczmarek. “The LMC and SMC are our nearest neighbours, so understanding how they evolve may help us understand how our Milky Way Galaxy will evolve.”

    “Understanding the role that magnetic fields play in the evolution of galaxies and their environment is a fundamental question in astronomy that remains to be answered.”

    The paper is one of a growing number of new results that are building a map of the Universe’s magnetism. According to Prof. Bryan Gaensler, Director of the Dunlap Institute for Astronomy & Astrophysics, University of Toronto, and a co-author on the paper, “Not only are entire galaxies magnetic, but the faint delicate threads joining galaxies are magnetic, too. Everywhere we look in the sky, we find magnetism.”

    The paper appeared in the Monthly Notices of the Royal Astronomical Society.

    See the full article here .

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    The Dunlap Institute is committed to sharing astronomical discovery with the public. Through lectures, the web, social and new media, an interactive planetarium, and major events like the Toronto Science Festival, we are helping to answer the public’s questions about the Universe.
    Our work is greatly enhanced through collaborations with the Department of Astronomy & Astrophysics, Canadian Institute for Theoretical Astrophysics, David Dunlap Observatory, Ontario Science Centre, Royal Astronomical Society of Canada, the Toronto Public Library, and many other partners.

    Established in 1827, the University of Toronto has one of the strongest research and teaching faculties in North America, presenting top students at all levels with an intellectual environment unmatched in depth and breadth on any other Canadian campus.

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  • richardmitnick 8:59 am on April 25, 2018 Permalink | Reply
    Tags: , , , , , Large Magellanic Cloud, ,   

    From Science Magazine: “European satellite reveals motions of more than 1 billion stars and shape of the Milky Way” 

    ScienceMag
    Science Magazine

    Apr. 25, 2018
    Daniel Clery

    1
    The Large Magellanic Cloud, one of the Milky Way’s nearest neighbors, may be more massive than previously thought. The image is not a photograph, but rather a map of the density of stars detected by Gaia in each pixel.
    DPAC/Gaia/ESA/Gaia

    Large Magellanic Cloud. Adrian Pingstone December 2003

    ESA/GAIA satellite

    “It’s like waiting for Christmas,” said Vasily Belokurov, an astronomer at the University of Cambridge in the United Kingdom last week. Today, the gifts arrived: the exact positions, motions, brightnesses, and colors of 1.3 billion stars in and around the Milky Way, as tracked by the European Space Agency’s (ESA’s) €750 million Gaia satellite, which after launch in 2013 began measuring the positions of stars and, over time, how they move. On 25 April, ESA made Gaia’s second data set—based on 22 months of observations—publicly available, which should enable a precise 3D map of large portions of the galaxy and the way it moves. “Nothing comes close to what Gaia will release,” Belokurov says.

    One might think that the galaxy is completely mapped. But large parts of it are obscured by gas and dust, and it is hard to discern structure from the vantage of the solar system. Gaia is not only expected to clarify the spiral structures of the galaxy today, but because the satellite traces how stars move, astronomers can wind the clock backward and see how the galaxy evolved over the past 13 billion years—a field known as galactic archaeology. With Gaia’s color and brightness information, astronomers can classify the stars by composition and identify the stellar nurseries where different types were born, to understand how chemical elements were forged and distributed.

    Gaia isn’t only about the Milky Way. For solar system scientists, the new data set will contain data on 14,000 asteroids. That’s a small fraction of the roughly 750,000 known minor bodies, but Gaia provides orbit information 100 times more accurate than before, says University of Cambridge astronomer Gerry Gilmore, who heads the U.K. branch of Gaia’s data processing consortium. That should help astronomers identify families of asteroids and trace how they relate to each other, shedding light on the solar system’s past and how planets formed from smaller bodies.

    See the full article here .

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  • richardmitnick 1:32 pm on February 23, 2018 Permalink | Reply
    Tags: , , , , , Large Magellanic Cloud, ,   

    From ALMA: “Large Magellanic Cloud Contains Surprisingly Complex Organic Molecules” 

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

    ALMA

    30 January, 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

    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

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

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

    1
    Astronomers using ALMA have uncovered chemical “fingerprints” of methanol, dimethyl ether, and methyl formate in the Large Magellanic Cloud. The latter two molecules are the largest organic molecules ever conclusively detected outside the Milky Way. The far-infrared image on the left shows the full galaxy. The zoom-in image shows the star-forming region observed by ALMA. It is a combination of mid-infrared data from Spitzer and visible (H-alpha) data from the Blanco 4-meter telescope. Credit: NRAO/AUI/NSF; ALMA (ESO/NAOJ/NRAO); Herschel/ESA; NASA/JPL-Caltech; NOAO

    NASA/Spitzer Infrared Telescope

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

    ESA/Herschel spacecraft

    The nearby dwarf galaxy known as the Large Magellanic Cloud (LMC) is a chemically primitive place.

    Large Magellanic Cloud. Adrian Pingstone December 2003

    Unlike the Milky Way, this semi-spiral collection of a few tens-of-billions of stars lacks our galaxy’s rich abundance of heavy elements, like carbon, oxygen, and nitrogen. With such a dearth of heavy elements, astronomers predict that the LMC should contain comparatively paltry amounts of complex carbon-based molecules. Previous observations of the LMC seem to support that view.

    New observations with the Atacama Large Millimeter/submillimeter Array (ALMA), however, have uncovered the surprisingly clear chemical “fingerprints” of the complex organic molecules methanol, dimethyl ether, and methyl formate. Though previous observations found hints of methanol in the LMC, the latter two are unprecedented findings and stand as the most complex molecules ever conclusively detected outside of our galaxy.

    Astronomers discovered the molecules’ faint millimeter-wavelength “glow” emanating from two dense star-forming embryos in the LMC, regions known as “hot cores.” These observations may provide insights into the formation of similarly complex organic molecules early in the history of the universe.

    “Even though the Large Magellanic Cloud is one of our nearest galactic companions, we expect it should share some uncanny chemical similarity with distant, young galaxies from the early universe,” said Marta Sewiło, an astronomer with NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author on a paper appearing in the Astrophysical Journal Letters.

    Astronomers refer to this lack of heavy elements as “low metallicity.” It takes several generations of star birth and star death to liberally seed a galaxy with heavy elements, which then get taken up in the next generation of stars and become the building blocks of new planets.

    “Young, primordial galaxies simply didn’t have enough time to become so chemically enriched,” said Sewiło. “Dwarf galaxies like the LMC probably retained this same youthful makeup because of their relatively low masses, which severely throttles back the pace of star formation.”

    “Due to its low metallicity, the LMC offers a window into these early, adolescent galaxies,” noted Remy Indebetouw, an astronomer at the National Radio Astronomy Observatory in Charlottesville, Virginia, and coauthor on the study. “Star-formation studies of this galaxy provide a stepping stone to understand star formation in the early universe.”

    The astronomers focused their study on the N113 Star Formation Region in the LMC, which is one of the galaxy’s most massive and gas-rich regions. Earlier observations of this area with NASA’s Spitzer Space Telescope and ESA’s Herschel Space Observatory revealed a startling concentration of young stellar objects – protostars that have just begun to heat their stellar nurseries, causing them to glow brightly in infrared light. At least a portion of this star formation is due to a domino-like effect, where the formation of massive stars triggers the formation of other stars in the same general vicinity.

    Sewiło and her colleagues used ALMA to study several young stellar objects in this region to better understand their chemistry and dynamics. The ALMA data surprisingly revealed the telltale spectral signatures of dimethyl ether and methyl formate, molecules that have never been detected so far from Earth.

    Complex organic molecules, those with six or more atoms including carbon, are some of the basic building blocks of molecules that are essential to life on Earth and – presumably – elsewhere in the universe. Though methanol is a relatively simple compound compared to other organic molecules, it nonetheless is essential to the formation of more complex organic molecules, like those that ALMA recently observed, among others.

    If these complex molecules can readily form around protostars, it’s likely that they would endure and become part of the protoplanetary disks of young star systems. Such molecules were likely delivered to the primitive Earth by comets and meteorites, helping to jumpstart the development of life on our planet.

    The astronomers speculate that since complex organic molecules can form in chemically primitive environments like the LMC, it’s possible that the chemical framework for life could have emerged relatively early in the history of the universe.
    Additional Information

    This research is presented in a paper titled “’The detection of hot cores and complex organic molecules in the Large Magellanic Cloud,” by M. Sewiło, et al., which appears in The Astrophysical Journal Letters.

    The research team was composed by Marta Sewilo [1], Remy Indebetouw [2, 3], Steven B. Charnley [1], Sarolta Zahorecz [4, 5], Joana M. Oliveira [6], Jacco Th. van Loon [6], Jacob L. Ward [7], C.-H. Rosie Chen [8], Jennifer Wiseman [1], Yasuo Fukui [9], Akiko Kawamura [10], Margaret Meixner [11], Toshikazu Onishi [4], and Peter Schilke [12].

    [1] NASA Postdoctoral Program Fellow, NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD 20771, USA
    [2] Department of Astronomy, University of Virginia, PO Box 400325, Charlottesville, VA 22904, USA
    [3] National Radio Astronomy Observatory, 520 Edgemont Rd, Charlottesville, VA 22903, USA
    [4] Department of Physical Science, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan
    [5] Chile Observatory, National Astronomical Observatory of Japan, National Institutes of Natural Science, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588, Japan
    [6] Lennard-Jones Laboratories, Keele University, ST5 5BG, UK
    [7] Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstr. 12-14, 69120 Heidelberg Germany
    [8] Max-Planck-Institut für Radioastronomie, Auf dem Hügel, 69 D-53121 Bonn, Germany
    [9] School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
    [10] National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
    [11] Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
    [12] I. Physikalisches Institut der Universität zu Köln, Zülpicher Str. 77, 50937, Köln, Germany

    See the full article here .

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

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

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  • richardmitnick 9:29 am on January 5, 2018 Permalink | Reply
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    From COSMOS: “Unlike Hollywood, the universe is full of big stars” 

    Cosmos Magazine bloc

    COSMOS Magazine

    05 January 2018
    Richard A Lovett

    Research finds massive star numbers have been underestimated – affecting calculations for black holes, neutron stars and gravitational waves.

    1
    This composite of 30 Doradus, aka the Tarantula Nebula, contains data from Chandra, Hubble, and Spitzer. Located in the Large Magellanic Cloud, the Tarantula Nebula is one of the largest star-forming regions close to the Milky Way. Universal History Archive / Contributor / Getty Images

    NASA/Chandra Telescope

    NASA/ESA Hubble Telescope

    NASA/Spitzer Infrared Telescope

    2
    Large Magellanic Cloud, NASA/ESA Hubble

    Giant stars hundreds of times more massive than the sun may have been much more common in the early universe than previously believed, astronomers say.

    The find, published in the journal Science, used the European Southern Observatory’s Very Large Telescope in Chile to examine about 800 stars in a “starburst” region called 30 Doradus (also known as the Tarantula Nebula) in the Large Magellanic Cloud, a galaxy about 160,000 light years away from the Milky Way.

    3
    30 Doradus, aka the Tarantula Nebula, ESO/VLT

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

    Using a spectrometer so sensitive it could pick out individual stars only 1.2 arcseconds apart (about 1/1500 the width of the full moon), the researchers counted substantially more high-mass stars – ranging from 30 to 200 times the mass of the sun – than predicted by long-standing models of star formation. Furthermore, the discrepancy was particularly large for the largest stars.

    Historically, astronomers have believed that the vast majority of stellar matter is in the form of myriad small stars, with only a fraction of it in giants of the type observed in 30 Doradus. (In fact, it was only recently that astronomers realized that the largest of these gigantic stars even existed.)

    But the new research appears to have stood the traditional notion on its head. “Our results suggest that a significant fraction [of the mass] is in high-mass stars,” says one of the authors, Chris Evans of the UK’s Astronomy Technology Centre, in Edinburgh, Scotland.

    That’s important, adds the study’s lead author, Fabian Schneider, an astrophysicist from the University of Oxford, because a star 100 times the mass of our sun isn’t equivalent to 100 suns.

    “These are extremely bright,” he says. “A 100 solar-mass star would be a million times brighter than our sun. You need only a handful of these to outshine all the others.”

    Such bright stars, he adds, are “cosmic engines” that blast out not only light but ionising radiation and strong stellar winds. They burn bright, but also die young in massive explosions that not only create black holes and neutron stars, but disperse the elements of planets — and life — into space: carbon, oxygen, silicon, iron, and many others.

    In the earliest universe, after it had cooled down from the initial fury of the Big Bang, there was nothing but hydrogen and helium, cold and dark, Schneider says. But about 150 million years later, astrophysicists believe that the infant universe’s “dark age” ended with the coalescing of these materials into the first stars and galaxies.

    The resulting burst of radiation not only brought light back to the universe, but produced a series of other important effects, including the production of ionising radiation, stellar winds, and supernovae. In combination, these shaped galaxies and slowed the rate of star formation enough to keep the first generation of stars from gobbling up all of the available matter.

    The result, Schneider says, was to “regulate” the star forming process “so that you [still] see stars forming today. Otherwise, it would have stopped early on.”

    In today’s universe, giant star-forming regions such as 30 Doradus are relatively rare. Ancient regions can still be studied by peering at distant galaxies, whose light has been traveling for billions of years, but these are far away and difficult to observe in detail.

    Having one nearby, where we can study it closely, is therefore a perfect opportunity, especially because 30 Doradus is so close and large that it is easily visible in a small telescope.

    And it is so bright that if it were in our own galaxy at the distance of the Orion Nebula’s star-forming cluster (easily visible to the naked eye) it would span an area 60 times larger than the full moon and cast visible shadows on cloudless nights, Schneider says.

    And while it doesn’t constitute a perfect laboratory – it has too many heavier elements, for example, to be a perfect analogy to star-forming regions in the earliest galaxies – the fact it contains so many super-massive stars has major ramifications for our understanding of our universe’s history.

    “There might [have been] 70% more supernovae, a tripling of the chemical yields and towards four times the ionising radiation from massive star populations,” says Schneider.

    “Also, the formation rate of black holes might be increased by 180%, directly translating into a corresponding increase of binary black hole mergers that have recently been detected via their gravitational wave signals.”

    Brad Tucker, an astrophysicist and cosmologist at Australian National University, calls the new study “a very good paper” with “wide-reaching impact.”

    Its authors, he adds comprise a “who’s who” of experts in the field.

    “[It] suggests we should expect more core-collapse supernovae, and thus more metals, in the early Universe,” he says. There should also be more black hole mergers to be detected in the future by the gravitational waves they produced.

    “Simply put,” he says, “more larger stars equals a more exciting universe.”

    See the full article here .

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  • richardmitnick 7:55 am on October 7, 2017 Permalink | Reply
    Tags: , , , Bubbles in space, , , Large Magellanic Cloud,   

    From ESA: “Bubbles in space” 

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    European Space Agency

    1
    Bubbles in space
    Released 06/10/2017
    Copyright NASA/ESA Hubble. Acknowledgements: Judy Schmidt CC BY 4.0

    At a distance of just 160 000 light-years, the Large Magellanic Cloud (LMC) is one of the Milky Way’s closest companions. It is also home to one of the largest and most intense regions of active star formation known to exist anywhere in our galactic neighbourhood — the Tarantula Nebula. This NASA/ESA Hubble Space Telescope image shows both the spindly, spidery filaments of gas that inspired the region’s name, and the intriguing structure of stacked “bubbles” that forms the so-called Honeycomb Nebula (to the lower left).

    The Honeycomb Nebula was found serendipitously by astronomers using ESO’s New Technology Telescope to image the nearby SN1987A, the closest observed supernova to Earth for over 400 years. The nebula’s strange bubble-like shape has baffled astronomers since its discovery in the early 1990s. Various theories have been proposed to explain its unique structure, some more exotic than others.

    In 2010, a group of astronomers studied the nebula and, using advanced data analysis and computer modelling, came to the conclusion that its unique appearance is likely due to the combined effect of two supernovae — a more recent explosion has pierced the expanding shell of material created by an older explosion. The nebula’s especially striking appearance is suspected to be due to a fortuitous viewing angle; the honeycomb effect of the circular shells may not be visible from another viewpoint.

    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 1:46 pm on July 5, 2017 Permalink | Reply
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    From U Cambridge: “Fastest stars in the Milky Way are ‘runaways’ from another galaxy” 

    U Cambridge bloc

    Cambridge University

    05 Jul 2017
    Sarah Collins
    sarah.collins@admin.cam.ac.uk

    1
    Artist’s impression of a runaway star. Credit: Amanda Smith, Institute of Astronomy.

    A group of astronomers have shown that the fastest-moving stars in our galaxy – which are travelling so fast that they can escape the Milky Way – are in fact runaways from a much smaller galaxy in orbit around our own. A group of astronomers have shown that the fastest-moving stars in our galaxy – which are travelling so fast that they can escape the Milky Way – are in fact runaways from a much smaller galaxy in orbit around our own.

    The researchers, from the University of Cambridge, used data from the Sloan Digital Sky Survey and computer simulations to demonstrate that these stellar sprinters originated in the Large Magellanic Cloud (LMC), a dwarf galaxy in orbit around the Milky Way.

    SDSS Telescope at Apache Point Observatory, NM, USA

    Large Magellanic Cloud. Adrian Pingstone December 2003

    These fast-moving stars, known as hypervelocity stars, were able to escape their original home when the explosion of one star in a binary system caused the other to fly off with such speed that it was able to escape the gravity of the LMC and get absorbed into the Milky Way. The results are published in the Monthly Notices of the Royal Astronomical Society, and will be presented today (5 July) at the National Astronomy Meeting in Hull.

    Astronomers first thought that the hypervelocity stars, which are large blue stars, may have been expelled from the centre of the Milky Way by a supermassive black hole. Other scenarios involving disintegrating dwarf galaxies or chaotic star clusters can also account for the speeds of these stars but all three mechanisms fail to explain why they are only found in a certain part of the sky.

    To date, roughly 20 hypervelocity stars have been observed, mostly in the northern hemisphere, although it’s possible that there are many more that can only be observed in the southern hemisphere.

    “Earlier explanations for the origin of hypervelocity stars did not satisfy me,” said Douglas Boubert, a PhD student at Cambridge’s Institute of Astronomy and the paper’s lead author. “The hypervelocity stars are mostly found in the Leo and Sextans constellations – we wondered why that is the case.”

    An alternative explanation to the origin of hypervelocity stars is that they are runaways from a binary system. In binary star systems, the closer the two stars are, the faster they orbit one another. If one star explodes as a supernova, it can break up the binary and the remaining star flies off at the speed it was orbiting. The escaping star is known as a runaway. Runaway stars originating in the Milky Way are not fast enough to be hypervelocity because blue stars can’t orbit close enough without the two stars merging. But a fast-moving galaxy could give rise to these speedy stars.

    The LMC is the largest and fastest of the dozens of dwarf galaxies in orbit around the Milky Way. It only has 10% of the mass of the Milky Way, and so the fastest runaways born in this dwarf galaxy can easily escape its gravity. The LMC flies around the Milky Way at 400 kilometres per second and, like a bullet fired from a moving train, the speed of these runaway stars is the velocity they were ejected at plus the velocity of the LMC. This is fast enough for them to be the hypervelocity stars.

    “These stars have just jumped from an express train – no wonder they’re fast,” said co-author Rob Izzard, a Rutherford fellow at the Institute of Astronomy. “This also explains their position in the sky, because the fastest runaways are ejected along the orbit of the LMC towards the constellations of Leo and Sextans.”
    Astronomers first thought that the hypervelocity stars, which are large blue stars, may have been expelled from the centre of the Milky Way by a supermassive black hole. Other scenarios involving disintegrating dwarf galaxies or chaotic star clusters can also account for the speeds of these stars but all three mechanisms fail to explain why they are only found in a certain part of the sky.

    To date, roughly 20 hypervelocity stars have been observed, mostly in the northern hemisphere, although it’s possible that there are many more that can only be observed in the southern hemisphere.

    “Earlier explanations for the origin of hypervelocity stars did not satisfy me,” said Douglas Boubert, a PhD student at Cambridge’s Institute of Astronomy and the paper’s lead author. “The hypervelocity stars are mostly found in the Leo and Sextans constellations – we wondered why that is the case.”

    An alternative explanation to the origin of hypervelocity stars is that they are runaways from a binary system. In binary star systems, the closer the two stars are, the faster they orbit one another. If one star explodes as a supernova, it can break up the binary and the remaining star flies off at the speed it was orbiting. The escaping star is known as a runaway. Runaway stars originating in the Milky Way are not fast enough to be hypervelocity because blue stars can’t orbit close enough without the two stars merging. But a fast-moving galaxy could give rise to these speedy stars.

    The LMC is the largest and fastest of the dozens of dwarf galaxies in orbit around the Milky Way. It only has 10% of the mass of the Milky Way, and so the fastest runaways born in this dwarf galaxy can easily escape its gravity. The LMC flies around the Milky Way at 400 kilometres per second and, like a bullet fired from a moving train, the speed of these runaway stars is the velocity they were ejected at plus the velocity of the LMC. This is fast enough for them to be the hypervelocity stars.

    “These stars have just jumped from an express train – no wonder they’re fast,” said co-author Rob Izzard, a Rutherford fellow at the Institute of Astronomy. “This also explains their position in the sky, because the fastest runaways are ejected along the orbit of the LMC towards the constellations of Leo and Sextans.”

    The researchers used a combination of data from the Sloan Digital Sky Survey and computer simulations to model how hypervelocity stars might escape the LMC and end up in the Milky Way. The researchers simulated the birth and death of stars in the LMC over the past two billion years, and noted down every runaway star. The orbit of the runaway stars after they were kicked out of the LMC was then followed in a second simulation that included the gravity of the LMC and the Milky Way. These simulations allow the researchers to predict where on the sky we would expect to find runaway stars from the LMC.

    “We are the first to simulate the ejection of runaway stars from the LMC – we predict that there are 10,000 runaways spread across the sky,” said Boubert. Half of the simulated stars which escape the LMC are fast enough to escape the gravity of the Milky Way, making them hypervelocity stars. If the previously known hypervelocity stars are runaway stars it would also explain their position in the sky.

    Massive blue stars end their lives by collapsing to a neutron star or black hole after hundreds of millions of years and runaway stars are no different. Most of the runaway stars in the simulation died ‘in flight’ after being kicked out of the LMC. The neutron stars and black holes that are left behind just continue on their way and so, along with the 10,000 runaway stars, the researchers also predict a million runaway neutron stars and black holes flying through the Milky Way.

    “We’ll know soon enough whether we’re right,” said Boubert. “The European Space Agency’s Gaia satellite will report data on billions of stars next year, and there should be a trail of hypervelocity stars across the sky between the Leo and Sextans constellations in the North and the LMC in the South.”

    ESA/GAIA satellite

    See the full article here .

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    U Cambridge Campus

    The University of Cambridge (abbreviated as Cantab in post-nominal letters) is a collegiate public research university in Cambridge, England. Founded in 1209, Cambridge is the second-oldest university in the English-speaking world and the world’s fourth-oldest surviving university. It grew out of an association of scholars who left the University of Oxford after a dispute with townsfolk. The two ancient universities share many common features and are often jointly referred to as “Oxbridge”.

    Cambridge is formed from a variety of institutions which include 31 constituent colleges and over 100 academic departments organised into six schools. The university occupies buildings throughout the town, many of which are of historical importance. The colleges are self-governing institutions founded as integral parts of the university. In the year ended 31 July 2014, the university had a total income of £1.51 billion, of which £371 million was from research grants and contracts. The central university and colleges have a combined endowment of around £4.9 billion, the largest of any university outside the United States. Cambridge is a member of many associations and forms part of the “golden triangle” of leading English universities and Cambridge University Health Partners, an academic health science centre. The university is closely linked with the development of the high-tech business cluster known as “Silicon Fen”.

     
  • richardmitnick 12:58 pm on March 30, 2017 Permalink | Reply
    Tags: , , , , Large Magellanic Cloud, ,   

    From Hubble: “Search For Stellar Survivor of a Supernova Explosion ” Hubble-Europe and USA/HubbleSite 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    NASA/ESA Hubble Telescope

    You-Hua Chu
    Institute of Astronomy and Astrophysics, Academia Sinica
    Taipei, Taiwan
    Tel: +886 2 2366 5300
    Email: yhchu@asiaa.sincia.edu.tw

    Mathias Jäger
    ESA/Hubble, Public Information Officer
    Garching bei München, Germany
    Tel: +49 176 62397500
    Email: mjaeger@partner.eso.org

    Christine Pulliam
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-6437
    cpulliam@stsci.edu

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4514
    villard@stsci.edu

    1
    A group of astronomers used Hubble to study the remnant of the Type Ia supernova explosion SNR 0509-68.7 — also known as N103B (seen at the top). The supernova remnant is located in the Large Magellanic Cloud, just over 160 000 light-years from Earth.

    2
    This ground-based image shows both the Small and the Large Magellanic Clouds — two satellite galaxies of the Milky Way. The Small Magellanic Cloud can be seen on the left, the Large Magellanic Cloud on the right. This photo was taken by the Japanese astrophotographer Akira Fujii.

    In contrast to many other Supernova remnants N103B does not appear to have a spherical shape but is strongly elliptical. Astronomers assume that part of material ejected by the explosion hit a denser cloud of interstellar material, which slowed its speed. The shell of expanding material being open to one side supports this idea.

    The relative proximity of N103B allows astronomers to study the life cycles of stars in another galaxy in great detail. And probably even to lift the veil on questions surrounding this type of supernova. The predictable luminosity of Type Ia supernovae means that astronomers can use them as cosmic standard candles to measure their distances, making them useful tools in studying the cosmos. Their exact nature, however, is still a matter of debate. Astronomers suspect Type Ia supernovae occur in binary systems in which at least one of the stars in the pair is a white dwarf [1].

    There are currently two main theories describing how these binary systems become supernovae. Studies like the one that has provided the new image of N103B — that involve searching for remnants of past explosions — can help astronomers to finally confirm one of the two theories.

    One theory assumes that both stars in the binary are white dwarfs. If the stars merge with one another it would ultimately lead to a supernova explosion of type Ia.

    The second theory proposes that only one star in the system is a white dwarf, while its companion is a normal star. In this theory material from the companion star is accreted onto the white dwarf until its mass reaches a limit, leading to a dramatic explosion. In that scenario, the theory indicates that the normal star should survive the blast in at least some form. However, to date no residual companion around any type Ia supernova has been found.

    Astronomers observed the N103B supernova remnant in a search for such a companion. They looked at the region in H-alpha — which highlights regions of gas ionised by the radiation from nearby stars — to locate supernova shock fronts. They hoped to find a star near the centre of the explosion which is indicated by the curved shock fronts. The discovery of a surviving companion would put an end to the ongoing discussion about the origin of type Ia supernova.

    And indeed they found one candidate star that meets the criteria — for star type, temperature, luminosity and distance from the centre of the original supernova explosion. This star has approximately the same mass as the Sun, but it is surrounded by an envelope of hot material that was likely ejected from the pre-supernova system.

    Although this star is a reasonable contender for N103B’s surviving companion, its status cannot be confirmed yet without further investigation and a spectroscopic confirmation. The search is still ongoing.

    Notes

    [1] A white dwarf is the small, dense core of a medium-mass star that is left behind after it has reached the end of its main-sequence lifetime and blown off its outer layers. Our own Sun is expected to become a white dwarf in around five billion years.

    See the full article here .

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    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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