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  • richardmitnick 10:34 am on January 8, 2020 Permalink | Reply
    Tags: "The Milky Way's impending galactic collision is already birthing new stars", , , , , Flatiron Institute's Center for Computational Astrophysics, Large and Small Magellanic Clouds, The Magellanic Stream   

    From Flatiron Institute’s Center for Computational Astrophysics: “The Milky Way’s impending galactic collision is already birthing new stars” 

    Flatiron Institute’s Center for Computational Astrophysics

    From Flatiron Institute’s Center for Computational Astrophysics

    January 7, 2020
    Thomas Sumner

    Newborn stars on the outskirts of our galaxy probably formed from material from two dwarf galaxies called the Magellanic Clouds.

    DISTANT NEIGHBORS: A newfound cluster of young stars (blue star) sits on the periphery of the Milky Way. These stars probably formed from material originating from neighboring dwarf galaxies called the Magellanic Clouds. D. Nidever; NASA

    The outskirts of the Milky Way are home to the galaxy’s oldest stars. But astronomers have spotted something unexpected in this celestial retirement community: a flock of young stars.

    More surprising still, spectral analysis suggests that the infant stars have an extragalactic origin. The stars seemingly formed not from material from the Milky Way, but from two nearby dwarf galaxies known as the Magellanic Clouds. Those galaxies are on a collision course with our own. The discovery suggests that a stream of gas extending from the galaxies is about half as far from crashing into the Milky Way as previously thought.

    FAR OUT: Astronomers have spotted a group of young stars (blue) on the outskirts of the Milky Way. The scientists propose that these stars formed from material from two dwarf galaxies known as the Magellanic Clouds. A. Price-Whelan

    “This is a puny cluster of stars — less than a few thousand in total — but it has big implications beyond its local area of the Milky Way,” says primary discoverer Adrian Price-Whelan, a research fellow at the Flatiron Institute’s Center for Computational Astrophysics in New York City. (The cluster also bears his name: Price-Whelan 1.)

    The newfound stars could reveal new insights into the Milky Way’s history; they might, for example, tell if the Magellanic Clouds collided with our galaxy in the past.

    Price-Whelan and his colleagues presented their findings January 8 at the American Astronomical Society meeting in Honolulu. They previously reported the discovery of Price-Whelan 1 on December 5 in The Astrophysical Journal and their subsequent spectroscopic analysis of the stars on December 16, also in The Astrophysical Journal.

    Identifying clusters of stars is tricky because our galaxy is chock-full of the radiant orbs. Some stars may appear to be close together in the sky but actually sit at drastically different distances from Earth. Other stars may temporarily neighbor one another but move on in opposite directions. Determining which stars are actually clustered together requires many precise measurements over time.

    Price-Whelan started with the latest data collected by the Gaia spacecraft, which has measured and cataloged the distances and motions of 1.7 billion stars. He searched the Gaia dataset for very blue stars, which are rare in the universe, and identified clumps of stars moving alongside them. After cross-matching with and removing known clusters, one remained.

    The newfound cluster is relatively young at 117 million years old and is on the far outskirts of the Milky Way. “It’s really, really far away,” Price-Whelan says. “It’s further than any known young stars in the Milky Way, which are typically in the disk. So right away, I was like, ‘Holy smokes, what is this?’”

    The cluster inhabits a region near a river of gas, dubbed the Magellanic Stream, that forms the outmost edge of the Large and Small Magellanic Clouds and reaches toward the Milky Way. Gas in the stream doesn’t contain much metal, unlike gases in the outer reaches of the Milky Way. David Nidever, assistant professor of physics at Montana State University in Bozeman, led an analysis of the metal content of the 27 brightest stars in the cluster. Just like the Magellanic Stream, the stars contain meager levels of metal.

    Magellanic Stream. https://lavinia.as.arizona.edu/~gbesla/The_Magellanic_Stream.html

    The researchers propose that the cluster formed as gas from the Magellanic Stream passed through the gases surrounding the Milky Way. This pass-through created a drag force that compressed the Magellanic Stream gas. This drag, along with tidal forces from the Milky Way’s gravitational tug, condensed the gas enough to trigger star formation. Over time, the stars zoomed ahead of the surrounding gas and joined the Milky Way.

    The stars’ presence presents a unique opportunity. Gauging the distance of gas from Earth is tricky and imprecise, so astronomers weren’t sure how far the Magellanic Stream was from reaching the Milky Way. The distance of stars, on the other hand, is comparatively trivial. Using the current positions and movements of stars in the cluster, the researchers predict that the edge of the Magellanic Stream is 90,000 light-years away from the Milky Way. That’s roughly half the distance previously predicted.

    “If the Magellanic Stream is closer, especially the leading arm closest to our galaxy, then it’s likely to be incorporated into the Milky Way sooner than the current model predicts,” Nidever says. “Eventually, that gas will turn into new stars in the Milky Way’s disk. Right now, our galaxy is using up gas faster than its being replenished. This extra gas coming in will help us replenish that reservoir and make sure that our galaxy continues to thrive and form new stars.”

    The updated distance to the Magellanic Stream will improve models of where the Magellanic Clouds have been and where they’re going, Price-Whelan says. The improved numbers could even settle a debate over whether the Magellanic Clouds have crossed through the Milky Way before. Finding an answer to that question will help astronomers better understand the history and properties of our galaxy.

    See the full article here .


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    The Center for Computational Astrophysics’s mission is to create new computational frameworks that allow scientists to analyze big astronomical datasets and to understand complex, multi-scale physics in astrophysical systems ranging in scales from planets to cosmology.

    Increasingly more sophisticated ground-based observatories and space missions are collecting data to make tremendous discoveries in astronomy and astrophysics, but to make those discoveries will require the combined power of theory, data analysis and simulation. CCA’s mission is to develop the computational tools needed for these simulations and analyses.

  • richardmitnick 10:22 am on March 31, 2019 Permalink | Reply
    Tags: "Cosmic Fireworks in the Clouds: Volunteer Detectives Sought for Magellanic Clouds Cluster Search", , , , , Large and Small Magellanic Clouds, NOAO-National Optical Astronomy Observatory   

    From NOAO: “Cosmic Fireworks in the Clouds: Volunteer Detectives Sought for Magellanic Clouds Cluster Search” 

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    From NOAO

    March 27, 2019

    Caught in a cosmic dance, our nearest neighbor galaxies, the Magellanic Clouds, are cartwheeling and circling each other as they fall toward our galaxy, the Milky Way. The gravitational interaction between the Clouds sparks cosmic fireworks—bursts of star formation as new clusters of stars flame on. How many and what kind of star clusters have been born this way over the history of the Clouds? A new project, the Local Group Cluster Search, invites citizen scientists to help find out!

    A portrait of the night sky taken from Cerro Tololo Inter-American Observatory in Chile showing the Large and Small Magellanic Clouds (upper and center left, respectively) with the Blanco 4-m telescope (lower right). The Blanco hosts the Dark Energy Camera (DECam), which was used to obtain the SMASH survey images of the Magellanic Clouds used by the Local Group Cluster Search. Inset images zoom in on three star-forming regions in the Large Magellanic Cloud as seen in SMASH survey images, showing strong emission from hot gas that surrounds newborn young massive stars.

    (Credit: Anja von der Linden / Stony Brook University; Inset: SMASH survey)

    Dark Energy Survey

    Dark Energy Camera [DECam], built at FNAL

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


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

    Large Magellanic Cloud. Adrian Pingstone December 2003

    A gallery of Magellanic Clouds star clusters, as seen in images from the SMASH survey. Star clusters span a wide range in size and brightness which vary depending on the age and mass of the cluster.

    (Credit: L.C. Johnson / Northwestern University)

    Our Nearest Galactic Neighbors

    Close enough to see with the naked eye when viewed from the southern hemisphere, the Magellanic Clouds have interacted in multiple close encounters over the past 2 billion years. During the encounters, gravitational forces push and pull on gas in the Clouds, sparking the formation of many new star clusters—“families” of hundreds to millions of stars—each formed from a single cloud of gas and dust.

    These clusters are useful to astronomers because they can be age-dated with great precision and used to reconstruct a historical record of star formation. By counting the number of clusters as a function of age, astronomers can back out the birthrate of clusters and chart the interaction history of the Clouds.

    A new citizen science project, the Local Group Cluster Search, aims to do just that by coupling new, high quality images of the Magellanic Clouds with a proven technique to find star clusters.

    SMASHingly Good Images

    The Local Group Cluster Search uses images from a new survey, the “Survey of the Magellanic Stellar History” (or SMASH for short).

    In contrast to the earliest studies of star clusters in the Magellanic Clouds, which used images captured on glass photographic plates, SMASH was carried out using the Dark Energy Camera (DECam), a 570-megapixel digital camera on the Blanco 4-m telescope at National Science Foundation’s (NSF) Cerro Tololo Inter-American Observatory in Chile. Using DECam, astronomers obtained images that not only cover the full extent of the two galaxies but also are more sensitive to faint stars than any previous wide-field optical survey of the Clouds.

    Explaining the challenge of surveying the Clouds, David Nidever, an astronomer at the National Optical Astronomy Observatory and Montana State University who leads the SMASH survey, said, “The Large and Small Magellanic Clouds are huge on the sky, covering more than 100 square degrees—an area larger than 500 full moons!” While it would take tens of thousands of tiled images from the Hubble Space Telescope’s largest camera to image the full sky area of the Clouds, DECam surveyed the main bodies of both Clouds with its immense field of view in fewer than 50 images.

    Human Eye Still the Best!

    Hosted by the Zooniverse online citizen science platform, the Local Group Cluster Search asks volunteers to examine small portions of the SMASH images and identify star clusters by eye. Citizen science searches are a great way to catalog clusters, even in today’s age of machine learning and artificial intelligence, because the human brain is highly skilled at pattern recognition.

    Cliff Johnson, a postdoctoral fellow at Northwestern University who leads the citizen science project, said, “While computer-based methods continue to improve, the varying backgrounds and appearance of star clusters in images of nearby galaxies make cluster identification difficult to automate. Algorithmic cluster searches have trouble eliminating false detections due to chance groupings of stars, while human-classified catalogs provide a reliable sample of clusters down to very faint brightness levels.”

    Building on Past Success

    Volunteer-led star cluster identification has a proven track record of success. In the earlier “Andromeda Project”, citizen scientists identified 2753 star clusters in the Andromeda galaxy. The results revealed that cluster formation varies with galactic environment. Through the Local Group Cluster Search, citizen scientists also recently completed a study of the Triangulum galaxy, identifying thousands of star clusters.

    With cluster censuses of Andromeda and Triangulum complete, the search now turns to the Magellanic Clouds, the only nearby galaxies yet to be searched by citizen scientists. What will the search reveal about the interaction history of our closest neighbors? Stay tuned!

    Join the search by visiting the project website at clustersearch.org.

    See the full article here .


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  • richardmitnick 9:22 pm on October 26, 2018 Permalink | Reply
    Tags: , , , , Large and Small Magellanic Clouds, , U-M astronomers confirm collision between two Milky Way satellite galaxies   

    From University of Michigan: “U-M astronomers confirm collision between two Milky Way satellite galaxies” 

    U Michigan bloc

    From University of Michigan

    October 25, 2018
    Morgan Sherburne

    This image shows an overview of the full Small Magellanic Cloud and was composed from two images from the Digitized Sky Survey 2, which digitized photographic surveys of the night sky. Image credit: Davide De Martin (NASA/ESA Hubble)

    Large Magellanic Cloud. Adrian Pingstone December 2003

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

    If you’re standing in the Southern Hemisphere on a clear night, you can see two luminous clouds offset from the Milky Way.

    These clouds of stars are satellite galaxies of the Milky Way, called the Small Magellanic Cloud and the Large Magellanic Cloud, or SMC and LMC.

    Using the newly released data from a new, powerful space telescope, University of Michigan astronomers have discovered that the southeast region, or “Wing,” of the Small Magellanic Cloud is moving away from the main body of that dwarf galaxy, providing the first unambiguous evidence that the Small and Large Magellanic Clouds recently collided.

    “This is really one of our exciting results,” said U-M professor of astronomy Sally Oey, lead author of the study. “You can actually see that the Wing is its own separate region that’s moving away from the rest of the SMC.”

    Their results are published in The Astrophysical Journal Letters.

    Together with an international team, Oey and undergraduate researcher Johnny Dorigo Jones were examining the SMC for “runaway” stars, or stars that have been ejected from clusters within the SMC. To observe this galaxy they were using a recent data release from Gaia, a new [not so new anymore, launched 19 December 2013] orbiting telescope launched by the European Space Agency.

    ESA/GAIA satellite

    Gaia is designed to image stars again and again over a period of several years in order to plot their movement in real time. That way, scientists can measure how stars move across the sky.

    “We’ve been looking at very massive, hot young stars—the hottest, most luminous stars, which are fairly rare,” Oey said. “The beauty of the Small Magellanic Cloud and the Large Magellanic Cloud is that they’re their own galaxies, so we’re looking at all of the massive stars in a single galaxy.”

    Arrows show the relative speed and directions of motion in the plane of the sky for the 315 targeted stars in the Small Magellanic Cloud. The red and blue colors show the relative speed in the line of sight, with red and blue corresponding to motion away from, and toward, the earth, respectively. To the left of the dashed line is the “Wing”
    region, showing a bulk motion away from the rest of the galaxy. In this image, north is up and east to the left. Image credit: Johnny Dorigo Jones

    Examining stars in a single galaxy helps the astronomers in two ways: First, it provides a statistically complete sample of stars in one parent galaxy. Second, this gives the astronomers a uniform distance to all the stars, which helps them measure their individual velocities.

    “It’s really interesting that Gaia obtained the proper motions of these stars. These motions contain everything we’re looking at,” Dorigo Jones said. “For example, if we observe someone walking in the cabin of an airplane in flight, the motion we see contains that of the plane, as well as the much slower motion of the person walking.

    “So we removed the bulk motion of the entire SMC in order to learn more about the velocities of individual stars. We’re interested in the velocity of individual stars because we’re trying to understand the physical processes occurring within the cloud.”

    Oey and Dorigo Jones study runaway stars to determine how they have been ejected from these clusters. In one mechanism, called the binary supernova scenario, one star in a gravitationally bound, binary pair explodes as a supernova, ejecting the other star like a slingshot. This mechanism produces X-ray-emitting binary stars.

    Another mechanism is that a gravitationally unstable cluster of stars eventually ejects one or two stars from the group. This is called the dynamical ejection scenario, which produces normal binary stars. The researchers found significant numbers of runaway stars among both X-ray binaries and normal binaries, indicating that both mechanisms are important in ejecting stars from clusters.

    In looking at this data, the team also observed that all the stars within the Wing—that southeast part of the SMC—are moving in a similar direction and speed. This demonstrates the SMC and LMC likely had a collision a few hundred million years ago.

    Study contributor Gurtina Besla, an astronomer at the University of Arizona, modeled the collision of the SMC and LMC. She and her team predicted a few years ago that a direct collision would cause the SMC Wing region to move toward the LMC, whereas if the two galaxies simply passed near each other, the Wing stars would be moving in a perpendicular direction. Instead, the Wing is moving away from the SMC, toward the LMC, said Oey, confirming that a direct collision occurred.

    “We want as much information about these stars as possible to better constrain these ejection mechanisms,” Dorigo Jones said. “Everyone loves marveling at images of galaxies and nebulae that are incredibly far away. The SMC is so close to us, however, that we can see its beauty in the night sky with just our naked eye. This fact, along with the data from Gaia, allow us to analyze the complex motions of stars within the SMC and even determine factors of its evolution.”

    The work was funded by the National Science Foundation.

    See the full article here .



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    U MIchigan Campus

    The University of Michigan (U-M, UM, UMich, or U of M), frequently referred to simply as Michigan, is a public research university located in Ann Arbor, Michigan, United States. Originally, founded in 1817 in Detroit as the Catholepistemiad, or University of Michigania, 20 years before the Michigan Territory officially became a state, the University of Michigan is the state’s oldest university. The university moved to Ann Arbor in 1837 onto 40 acres (16 ha) of what is now known as Central Campus. Since its establishment in Ann Arbor, the university campus has expanded to include more than 584 major buildings with a combined area of more than 34 million gross square feet (781 acres or 3.16 km²), and has two satellite campuses located in Flint and Dearborn. The University was one of the founding members of the Association of American Universities.

    Considered one of the foremost research universities in the United States,[7] the university has very high research activity and its comprehensive graduate program offers doctoral degrees in the humanities, social sciences, and STEM fields (Science, Technology, Engineering and Mathematics) as well as professional degrees in business, medicine, law, pharmacy, nursing, social work and dentistry. Michigan’s body of living alumni (as of 2012) comprises more than 500,000. Besides academic life, Michigan’s athletic teams compete in Division I of the NCAA and are collectively known as the Wolverines. They are members of the Big Ten Conference.

  • richardmitnick 6:06 pm on April 30, 2018 Permalink | Reply
    Tags: , , , , , Large and Small Magellanic Clouds,   

    From astrobites: “Snake (on a Plane) in the Clouds” 

    Astrobites bloc


    Title: Snake in the Clouds: A new nearby dwarf galaxy in the Magellanic bridge
    Authors: Sergey E. Koposov, Matthew G. Walker, Vasily Belokurov, Andrew R. Casey, Alex Geringer-Sameth, Dougal Mackey, Gary Da Costa, Denis Erkal, Prashin Jethwa, Mario Mateo, Edward W. Olszewski, John I. Bailey III
    First Author’s Institutions: McWilliams Center for Cosmology, Carnegie Mellon University, Pittsburgh, PA, USA; Institute for Astronomy, University of Cambridge, UK

    Status: Submitted to MNRAS [open access on arXiv]

    The Magellanic Clouds are two prominent splotches of light visible in the sky of the Southern Hemisphere.

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

    Large Magellanic Cloud. Adrian Pingstone December 2003

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

    Named for their relative sizes, the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC) are two dwarf galaxies, satellites of the Milky Way which are believed to have been pulled into the domain of our galaxy some several billion years ago. During this accretion event, gravitational interactions flung a wide field of debris from the Clouds. While studying the Magellanic Bridge between the two Clouds, the authors of today’s paper found another piece of the puzzle: an intriguing little dwarf galaxy occupying the bridge of debris. Dubbed Hydrus I after the constellation of sky it occupies, a preliminary investigation of this ultra-faint dwarf galaxy (UFD) is the focus of today’s paper.

    See the full article here .

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    Astrobites is a daily astrophysical literature journal written by graduate students in astronomy. Our goal is to present one interesting paper per day in a brief format that is accessible to undergraduate students in the physical sciences who are interested in active research.
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    Reading a technical paper from an unfamiliar subfield is intimidating. It may not be obvious how the techniques used by the researchers really work or what role the new research plays in answering the bigger questions motivating that field, not to mention the obscure jargon! For most people, it takes years for scientific papers to become meaningful.
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  • richardmitnick 1:44 pm on April 2, 2018 Permalink | Reply
    Tags: , , , , Large and Small Magellanic Clouds, This Is How The Milky Way Is Eating Our Galactic Neighbors   

    From Ethan Siegel: “This Is How The Milky Way Is Eating Our Galactic Neighbors” 

    From Ethan Siegel

    A map of star density in the Milky Way and surrounding sky, clearly showing the Milky Way, the Large and Small Magellanic Clouds (our two largest satellite galaxies), and if you look more closely, NGC 104 to the left of the SMC, NGC 6205 slightly above and to the left of the galactic core, and NGC 7078 slightly below. (ESA/GAIA)

    ESA/GAIA satellite

    Two major galaxies in the local group are already in the process of being devoured by us… and each other.

    The Milky Way is the second-largest galaxy in our local group, which contains some 60 galaxies of various sizes.

    Local Group. Andrew Z. Colvin 3 March 2011

    Our Local Group of galaxies is dominated by Andromeda and the Milky Way, but our cosmic neck-of-the-woods contains many dwarf galaxies clustered around each of the large members. The Large Magellanic Cloud is the fourth biggest galaxy in the local group, and the Small Magellanic Cloud is either 5th, 6th, or 7th, as the uncertainties between it, NGC 6822 and NGC 3190 make it impossible to tell who’s larger. (Andrew Z. Colvin)

    Small galaxies are found all across our neighborhood, with many clustered around the largest members:

    Andromeda Galaxy Adam Evans

    ourselves, and Triangulum.

    The VLT Survey Telescope (VST) at ESO’s Paranal Observatory in Chile has captured this beautifully detailed image of the galaxy Messier 33, often called the Triangulum Galaxy. This nearby spiral, the second closest large galaxy to our own galaxy, the Milky Way, is packed with bright star clusters, and clouds of gas and dust. This picture is amongst the most detailed wide-field views of this object ever taken and shows the many glowing red gas clouds in the spiral arms with particular clarity.

    ESO VST telescope, at ESO’s Cerro Paranal Observatory,with an elevation of 2,635 metres (8,645 ft) above sea level

    The Large (top right) and Small (lower left) Magellanic Clouds are visible in the southern skies, and helped guide Magellan on his famous voyage some 500 years ago. In reality, the LMC is located some 165,000 light years away, with the SMC slightly farther at 198,000 light years. (ESO/S. Brunier)

    Two of the largest dwarfs, the Large and Small Magellanic Clouds, are located less than 200,000 light years from Earth.

    The Atacama Large Millimetre/submillimetre Array, as photographed with the Magellanic clouds overhead. (ESO/C. Malin)

    Although they’re only between 0.1%-1% the Milky Way’s mass, these irregular, dwarf neighbors are full of interesting, new stars.

    The Large Magellanic Cloud, the fourth largest galaxy in our local group, with the giant star-forming region of the Tarantula Nebula just to the right and below the main galaxy. (NASA, from Wikimedia Commons user Alfa pyxisdis)

    New star formation is triggered by mutual gravitational interactions combined with the Milky Way’s tug.

    The Large Magellanic Cloud is home to the closest supernova of the last century. The pink regions here are not artificial, but are signals of ionized hydrogen and active star formation, likely triggered by gravitational interactions and tidal forces. (Jesús Peláez Aguado)

    The gas within these galaxies gets shunted into new clusters, including the local group’s largest star-forming region: 30 Doradus.

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

    The cluster RMC 136 (R136) in the Tarantula Nebula in the Large Magellanic Cloud, is home to the most massive stars known. R136a1, the greatest of them all, is over 250 times the mass of the Sun.(European Southern Observatory/P. Crowther/C.J. Evans)

    But these gravitational interactions also strip the gas away from these dwarfs, where the Milky Way will devour it.

    In an interaction between two galaxies, small galaxies are gravitationally stretched and torn apart. Most of that material will eventually fall back onto the larger one. If a larger, third galaxy is present, it can help siphon off and steal the gas from the smaller, closely bound dwarfs. (Katharine Johnston)

    In a cosmic tug-of-war between two dwarf galaxies orbiting the Milky Way, only NASA’s Hubble Space Telescope can see who’s winning. The players are the Large and Small Magellanic Clouds, and as they gravitationally tug at each other, one of them has pulled out a huge amount of gas from its companion. This shredded and fragmented gas, called the Leading Arm (in pink, as imaged in the radio part of the spectrum), is being devoured by the Milky Way and feeding new star birth in our galaxy. (Illustration: D. Nidever et al., NRAO/AUI/NSF and A. Mellinger, Leiden-Argentine-Bonn (LAB) Survey, Parkes Observatory, Westerbork Observatory, Arecibo Observatory, and A. Feild (STScI); Science: NASA, ESA, and A. Fox (STScI))

    NASA/ESA Hubble Telescope

    CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia

    Westerbork Synthesis Radio Telescope, an aperture synthesis interferometer near World War II Nazi detention and transit camp Westerbork, north of the village of Westerbork, Midden-Drenthe, in the northeastern Netherlands

    NAIC/Arecibo Observatory, Puerto Rico, USA, at 497 m (1,631 ft) , built into the landscape at Arecibo, Puerto Rico.
    NOAO/AURA/NSF/H. Schweiker/WIYN

    Until, that is, scientists led by Andrew Fox [The Astrophysical Journal] looked at the absorption effects of this gas from background quasar light.

    An ultra-distant quasar will encounter gas clouds on the light’s journey to Earth, allowing us to measure all sorts of parameters, including absorption abundances. The ‘leading arm’ arising from the interaction of the LMC and SMC shows the cosmic fingerprint of the gas, and it matches the small cloud, not the large one. (Ed Janssen, ESO)

    The cosmic fingerprints matched the Small, not Large, Magellanic Cloud.

    The Small Magellanic Cloud, viewed in infrared light through the ESO’s VISTA instrument, consists of a variety of stars, including new stars, but very little gas. What little gas remains inside matches the cosmic fingerprint of the ‘leading arm’ stream found around the Milky Way. (ESO/VISTA VMC)

    While the Milky Way will eventually devour both, large dwarfs strip the gas away from smaller ones, hastening their demise.

    See the full article here .

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    “Starts With A Bang! is a blog/video blog about cosmology, physics, astronomy, and anything else I find interesting enough to write about. I am a firm believer that the highest good in life is learning, and the greatest evil is willful ignorance. The goal of everything on this site is to help inform you about our world, how we came to be here, and to understand how it all works. As I write these pages for you, I hope to not only explain to you what we know, think, and believe, but how we know it, and why we draw the conclusions we do. It is my hope that you find this interesting, informative, and accessible,” says Ethan

  • richardmitnick 8:40 am on December 1, 2017 Permalink | Reply
    Tags: AAO AAT, , , , , Large and Small Magellanic Clouds, ,   

    From AAO via Manu Garcia at IAC: ” The shooting stars of the Magellanic Clouds” 

    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.

    AAO Australian Astronomical Observatory

    Australian Astronomical Observatory

    November 29, 2017
    Kirsten Banks
    Ángel López-Sánchez

    The Magellanic Clouds over the Anglo-Australian Telescope (AAT, Siding Spring Observatory, Australia).
    Superimposed false color distribution of atomic gas shown in both dwarfs and Magellan bridge connecting the two. The black rectangle indicates the region of sky explored in AAT observations, enlargement shows the position of the “lost stars” of the SMC (identified as bright spots in image grayscale) found. Credits: Image of the Magellanic Clouds on AAT: Angel R. Lopez-Sanchez (AAO / MQU). Radio image showing the gas HI: M. Putman (Columbia, US) and Leiden / Argentine / Bonn (LAB) survey of Galactic H I (Kalberla & Haud 2015). Grayscale image: Digital Sky Survey (DSS). Image composition: Ricardo Carrera (IAC / INAF) and Angel R. Lopez-Sanchez (AAO / MQU).

    Using the Anglo-Australian Telescope (AAT), an international team of astrophysicists has confirmed the existence of stars in the Magellanic Bridge, a gaseous structure connecting the two Magellanic Clouds. These “lost stars” were stripped from the Small Magellanic Cloud by the gravitational pull of the Large Magellanic Cloud in a recent nearby encounter. The results of this research were recently published in the journal <a href="http://Using the Anglo-Australian Telescope (AAT), an international team of astrophysicists has confirmed the existence of stars in the Magellanic Bridge, a gaseous structure connecting the two Magellanic Clouds. These “lost stars” were stripped from the Small Magellanic Cloud by the gravitational pull of the Large Magellanic Cloud in a recent nearby encounter.Paper in MNRAS.

    Our galaxy, the Milky Way has two small galaxies “satellite” around: the Magellanic Clouds.

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

    Large Magellanic Cloud. Adrian Pingstone December 2003

    Only visible from the Southern Hemisphere, the Small and the Large Magellanic Cloud (SMC and LMC, respectively, for its acronym in English) look like two isolated objects, but in reality, both galaxies are linked by a structure of gas: Bridge Magallanes . The material of the bridge has been started Cloud Magellan as a result of interactions between them.

    The Large and Small Magellanic Clouds, their stellar halos and the RR Lyrae bridge: pale white veils and the narrow bridge between the Clouds represent the distribution of the RR Lyrae stars detected with the data from ESA’s Gaia satellite. Image credit: V. Belokurov / D. Erkal / A. Mellinger.

    ESA/GAIA satellite

    Using the 3.9m Anglo-Australian Telescope (AAT), located at Siding Spring Observatory (Coonabarabran, Australia) and managed by the Australian Astronomical Observatory (AAO), an international team of astrophysicists has confirmed, for the first time, the detection of stars within the Magellanic Bridge.

    2dF robot Anglo-Australian Telescope moving optical fibers which are illuminated in red. Credit: Angel R. Lopez-Sanchez (AAO / MQU), together with the AAOmega spectrograph to measure around 1500 stars in that region of the sky.

    ANU AAOmega spectrograph Anglo Australian Telescope

    The 2dF robot, a pioneer in the world, can simultaneously observe objects 400 in a region of sky whose diameter is equal to 4 moons. Thus it is possible to obtain high quality data from a large number of stars in just a few nights, “said Angel Lopez-Sanchez, PhD in Astrophysics from the University of La Laguna (ULL) and the IAC, an astrophysicist at the AAO and team member investigator.

    Access to AAT has been made possible by the OPTICON program framework of the European Union 7 program that allows access to facilities where a different source for researchers European country involved,” says Ricardo Carrera, a researcher at IAC and first author of the study.

    Observations with 2dF revealed that certain stars within the region of the sky where the bridge is Magallanes move differently than they do the stars of the Milky Way. However, their movement coincides with the Magellanic Bridge. The data were used to estimate the age of these “wandering stars” is between one thousand and ten billion years. However, the Puente de Magallanes was formed about 200 million years ago, much younger than the stars now detected in age, so really these stars had to be torn from one of the two galaxies (or perhaps both).

    The AAT observations revealed that some stars within the region where the Magellanic Bridge is located are not moving with the Milky Way. Instead, the movement of these stars agrees with that of the gas of the Magellanic Bridge.

    The researchers discovered that these “lost stars” are very old, born between 1 and 10 billion years ago.

    The Magellanic Bridge was only formed around 200 million years ago, much more recently than the stars associated with it, meaning that the “lost stars” were actually born within the LMC or the SMC and later stripped from the galaxies.

    Some dynamical models explaining the formation and evolution of the Magellanic Bridge already predicted that both stars and gas should be present. These new observations have confirmed, for the first time, that this is true.

    “Although preliminary studies suggested the existence of stars within the Magellanic Bridge, the data obtained with the AAT have definitively confirmed the existence of these old ‘lost stars’”, says Dr Carrera.

    “An important part of the gas and the stars in the Magellanic Clouds was “stripped” by effect of the gravitational forces. Comparing with dynamical models it is possible to estimate that this happened around 200 million years ago, when the two dwarf galaxies were very close. This was the origin of the Magellanic Bridge”, says Dr Noelia E. D. Noël, lecturer in Astrophysics at the University of Surrey in the UK.

    Furthermore, the spectroscopic data provided by the AAT have been also used to estimate the chemical composition of the “lost stars” found within the Magellanic Bridge.

    “Combining both the kinematics and the chemical composition of the stars, we can unequivocally conclude that these stars were actually born in the Small Magellanic Cloud”, says Dr Ricardo Carrera.

    Galaxy interactions and mergers were very common in the early Universe, and they are still happening today. Indeed, galaxy evolution is largely dominated by these encounters.

    “Galaxy interactions can distort or even drastically change the morphology of the galaxies. During these encounters there is an interchange of material between galaxies, new star-forming regions are created, and frequently the gas and stars are also stripped into the space between galaxies, called the intergalactic medium”, says Dr Ángel López-Sánchez.

    Dynamic models that explain the formation of Puente de Magallanes had already predicted that the gas should be accompanied by a stellar component, but these observations have been confirmed that for the first time, that this is so. “Although there were some indications of the existence of these stars, the data obtained with the AAT have allowed for the first time confirmed the existence of these” “much older than the Magellanic Bridge” wandering stars, says Carrera.

    “Much of the gas and stars in the Magellanic Clouds was ‘ripped off’ by tidal forces. Comparing with dynamic models can conclude that this occurred about 200 million years ago when two galaxies had a great approach including which the Puente de Magallanes was born, “says Noelia ED Noël, PhD in Astrophysics from the University of La Laguna (ULL) and the IAC and currently a researcher at the University of Surrey in the UK.

    The tidal forces acting on the galaxies are similar to those that cause tides in Earth’s oceans due to the gravitational pull of the moon, but the spectroscopic data obtained in the AAT have also served to determine the chemical composition of the detected stars within the Magellanic Bridge. “By combining information on the composition of these stars and their kinematics have determined unequivocally that these stars were created in the Small Magellanic Cloud,” says Carrera.

    Interactions and mergers between galaxies were very common in the early universe, but today are still frequent. So much so that the evolution of galaxies is dominated by these meetings. “The interactions between galaxies can distort and even radically alter the morphology of the systems involved. During these approaches there is exchange of material between them, creating regions where new stars are formed and starting often gas and stars, “said Lopez-Sanchez.

    See the full article here .

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    Anglo-Australian telescope

    The Australian Astronomical Observatory, a division of the Department of Industry, Innovation and Science, operates the Anglo-Australian and UK Schmidt telescopes on behalf of the astronomical community of Australia. To this end the Observatory is part of and is funded by the Australian Government. Its function is to provide world-class observing facilities for Australian optical astronomers.

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