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  • richardmitnick 1:21 pm on May 22, 2015 Permalink | Reply
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    From Hubble: “Hubble’s Look at an Extragalactic Peculiarity” 

    NASA Hubble Telescope

    Hubble

    May 22, 2015
    Karl Hille

    1
    NASA/ESA Hubble

    This galaxy goes by the name of ESO 162-17 and is located about 40 million light-years away in the constellation of Carina. At first glance this image seems like a fairly standard picture of a galaxy with dark patches of dust and bright patches of young, blue stars. However, a closer look reveals several peculiar features.

    Firstly, ESO 162-17 is what is known as a peculiar galaxy — a galaxy that has gone through interactions with its cosmic neighbors, resulting in an unusual amount of dust and gas, an irregular shape, or a strange composition.

    Secondly, on February 23, 2010 astronomers observed the supernova known as SN 2010ae nestled within this galaxy. The supernova belongs to a recently discovered class of supernovae called Type Iax supernovae. This class of objects is related to the better known Type-Ia supernovae.

    Type Ia supernovae result when a white dwarf accumulates enough mass either from a companion or, rarely, through collision with another white dwarf, to initiate a catastrophic collapse followed by a spectacular explosion as a supernova. Type Iax supernovae also involve a white dwarf as the central star, but in this case it may survive the event. Type Iax supernovae are much fainter and rarer than Type Ia supernovae, and their exact mechanism is still a matter of open debate.

    The rather beautiful four-pointed shape of foreground stars distributed around ESO 162-17 also draws the eye. This is an optical effect introduced as the incoming light is diffracted by the four struts that support the Hubble Space Telescope’s small secondary mirror.

    See the full article here.

    Please help promote STEM in your local schools.

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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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  • richardmitnick 1:05 pm on May 22, 2015 Permalink | Reply
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    From Hubble: “Hubble Revisits Tangled NGC 6240″ 

    NASA Hubble Telescope

    Hubble

    May 22, 2015
    Ashley Morrow

    1
    Image credit: NASA, ESA, the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration, and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University)

    Not all galaxies are neatly shaped, as this new NASA/ESA Hubble Space Telescope image of NGC 6240 clearly demonstrates. Hubble previously released an image of this galaxy back in 2008, but the knotted region, shown here in a pinky-red hue at the center of the galaxies, was only revealed in these new observations from Hubble’s Wide Field Camera 3 and Advanced Camera for Surveys.

    NASA Hubble WFC3
    WFC3

    NASA Hubble ACS
    ACS

    NGC 6240 lies 400 million light-years away in the constellation of Ophiuchus (The Serpent Holder). This galaxy has an elongated shape with branching wisps, loops and tails. This mess of gas, dust and stars bears more than a passing resemblance to a butterfly and a lobster.

    This bizarrely-shaped galaxy did not begin its life looking like this; its distorted appearance is a result of a galactic merger that occurred when two galaxies drifted too close to one another. This merger sparked bursts of new star formation and triggered many hot young stars to explode as supernovae. A new supernova, not visible in this image was discovered in this galaxy in 2013, named SN 2013dc.

    At the center of NGC 6240 an even more interesting phenomenon is taking place. When the two galaxies came together, their central black holes did so, too. There are two supermassive black holes within this jumble, spiraling closer and closer to one another. They are currently only some 3,000 light-years apart, incredibly close given that the galaxy itself spans 300,000 light-years. This proximity secures their fate as they are now too close to escape each other and will soon form a single immense black hole.

    See the full article here.

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    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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  • richardmitnick 5:00 pm on May 21, 2015 Permalink | Reply
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    From Hubble: “Hubble Observes One-of-a-Kind Star Nicknamed ‘Nasty'” 

    NASA Hubble Telescope

    Hubble

    May 21, 2015
    Donna Weaver / Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4493 / 410-338-4514
    dweaver@stsci.edu / villard@stsci.edu

    1
    Object Name: NaSt1, Wolf-Rayet 122, WR 122
    Object Description: Emission-line Star with Nebula
    Instrument: WFC3/UVIS
    Exposure Date(s): April 27, 2013
    Credit: NASA, ESA, and J. Mauerhan (University of California, Berkeley)
    Release Date: May 21, 2015

    Astronomers using NASA’s Hubble Space Telescope have uncovered surprising new clues about a hefty, rapidly aging star whose behavior has never been seen before in our Milky Way galaxy. In fact, the star is so weird that astronomers have nicknamed it “Nasty 1,” a play on its catalog name of NaSt1. The star may represent a brief transitory stage in the evolution of extremely massive stars.

    First discovered several decades ago, Nasty 1 was identified as a Wolf-Rayet star, a rapidly evolving star that is much more massive than our sun. The star loses its hydrogen-filled outer layers quickly, exposing its super-hot and extremely bright helium-burning core.

    But Nasty 1 doesn’t look like a typical Wolf-Rayet star. The astronomers using Hubble had expected to see twin lobes of gas flowing from opposite sides of the star, perhaps similar to those emanating from the massive star Eta Carinae, which is a Wolf-Rayet candidate.

    2
    A huge, billowing pair of gas and dust clouds are captured in this stunning NASA Hubble Space Telescope image of the supermassive star Eta Carinae.

    Instead, Hubble revealed a pancake-shaped disk of gas encircling the star. The vast disk is nearly 2 trillion miles wide, and may have formed from an unseen companion star that snacked on the outer envelope of the newly formed Wolf-Rayet. Based on current estimates, the nebula surrounding the stars is just a few thousand years old, and as close as 3,000 light-years from Earth.

    “We were excited to see this disk-like structure because it may be evidence for a Wolf-Rayet star forming from a binary interaction,” said study leader Jon Mauerhan of the University of California, Berkeley. “There are very few examples in the galaxy of this process in action because this phase is short-lived, perhaps lasting only a hundred thousand years, while the timescale over which a resulting disk is visible could be only ten thousand years or less.”

    According to the team’s scenario, a massive star evolves very quickly, and as it begins to run out of hydrogen, it swells up. Its outer hydrogen envelope becomes more loosely bound and vulnerable to gravitational stripping, or a type of stellar cannibalism, by the nearby companion star. In that process, the more compact star winds up gaining mass, and the original massive star loses its hydrogen envelope, exposing its helium core to become a Wolf-Rayet star.

    Another way Wolf-Rayet stars are said to form is when a massive star ejects its own hydrogen envelope in a strong stellar wind streaming with charged particles. The binary interaction model where a companion star is present is gaining traction because astronomers realize that at least 70 percent of massive stars are members of double-star systems. Direct mass loss alone also cannot account for the number of Wolf-Rayet stars relative to other less-evolved massive stars in the galaxy.

    “We’re finding that it is hard to form all the Wolf-Rayet stars we observe by the traditional wind mechanism, because mass loss isn’t as strong as we used to think,” said Nathan Smith of the University of Arizona in Tucson, who is a co-author on the new NaSt1 paper. “Mass exchange in binary systems seems to be vital to account for Wolf-Rayet stars and the supernovae they make, and catching binary stars in this short-lived phase will help us understand this process.”

    But the mass-transfer process in mammoth binary systems isn’t always efficient. Some of the stripped matter can spill out during the dynamical gravitational tussle between the stars, creating a disk around the binary.

    “That’s what we think is happening in Nasty 1,” Mauerhan said. “We think there is a Wolf-Rayet star buried inside the nebula, and we think the nebula is being created by this mass-transfer process. So this type of sloppy stellar cannibalism actually makes Nasty 1 a rather fitting nickname.”

    The star’s catalog name, NaSt1, is derived from the first two letters of each of the two astronomers who discovered it in 1963, Jason Nassau and Charles Stephenson.

    Viewing the Nasty 1 system hasn’t been easy. The system is so heavily cloaked in gas and dust, it blocks even Hubble’s view of the stars. So Mauerhan’s team cannot measure the mass of each star, the distance between them, or the amount of material spilling onto the companion star.

    Previous observations of Nasty 1 have provided some information on the gas in the disk. The material, for example, is travelling about 22,000 miles per hour in the outer nebula, slower than similar stars. The comparatively slow speed indicates that the star expelled its material through a less violent event than Eta Carinae’s explosive outbursts, where the gas is travelling hundreds of thousands of miles per hour.

    Nasty 1 may also be shedding the material sporadically. Past studies in infrared light have shown evidence for a compact pocket of hot dust very close to the central stars. Recent observations by Mauerhan and colleagues at the University of Arizona, using the Magellan telescope at Las Campanas Observatory in Chile, have resolved a larger pocket of cooler dust that may be indirectly scattering the light from the central stars.

    Magellan 6.5 meter telescopes
    Magellan 6.5 meter Interior
    Magellan Telescope

    The presence of warm dust implies that it formed very recently, perhaps in spurts, as chemically enriched material from the two stellar winds collides at different points, mixes, flows away, and cools. Sporadic changes in the wind strength or the rate the companion star strips the main star’s hydrogen envelope might also explain the clumpy structure and gaps seen farther out in the disk.

    To measure the hypersonic winds from each star, the astronomers turned to NASA’s Chandra X-ray Observatory.

    NASA Chandra Telescope
    Chandra

    The observations revealed scorching hot plasma, indicating that the winds from both stars are indeed colliding, creating high-energy shocks that glow in X-rays. These results are consistent with what astronomers have observed from other Wolf-Rayet systems.

    The chaotic mass-transfer activity will end when the Wolf-Rayet star runs out of material. Eventually, the gas in the disk will dissipate, providing a clear view of the binary system.

    “What evolutionary path the star will take is uncertain, but it will definitely not be boring,” said Mauerhan. “Nasty 1 could evolve into another Eta Carinae-type system. To make that transformation, the mass-gaining companion star could experience a giant eruption because of some instability related to the acquiring of matter from the newly formed Wolf-Rayet. Or, the Wolf-Rayet could explode as a supernova. A stellar merger is another potential outcome, depending on the orbital evolution of the system. The future could be full of all kinds of exotic possibilities depending on whether it blows up or how long the mass transfer occurs, and how long it lives after the mass transfer ceases.”

    The team’s results will appear May 21 in the online edition of the Monthly Notices of the Royal Astronomical Society.

    See the full article here.

    Please help promote STEM in your local schools.

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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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  • richardmitnick 2:08 pm on May 14, 2015 Permalink | Reply
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    From Hubble: “Hubble Catches a Stellar Exodus in Action” 

    NASA Hubble Telescope

    Hubble

    May 14, 2015
    CONTACT
    Donna Weaver / Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4493 / 410-338-4514
    dweaver@stsci.edu / villard@stsci.edu

    Felicia Chou
    NASA Headquarters, Washington, DC
    202-358-0257
    felicia.chou@nasa.gov

    Jeremy Heyl
    University of British Columbia, Vancouver, BC, Canada
    604-822-0995
    heyl@phas.ubc.ca

    Temp 0
    White Dwarfs Migrating from Globular Cluster 47 Tucanae’s Core

    Using NASA’s Hubble Space Telescope, astronomers have captured for the first time snapshots of fledgling white dwarf stars beginning their slow-paced, 40-million-year migration from the crowded center of an ancient star cluster to the less populated suburbs.

    White dwarfs are the burned-out relics of stars that rapidly lose mass, cool down, and shut off their nuclear furnaces. As these glowing carcasses age and shed weight, their orbits begin to expand outward from the star cluster’s packed downtown. This migration is caused by a gravitational tussle among stars inside the cluster. Globular star clusters sort out stars according to their mass, governed by a gravitational billiard-ball game where lower mass stars rob momentum from more massive stars. The result is that heavier stars slow down and sink to the cluster’s core, while lighter stars pick up speed and move across the cluster to the edge. This process is known as “mass segregation.” Until these Hubble observations, astronomers had never definitively seen the dynamical conveyor belt in action.

    Astronomers used Hubble to watch the white-dwarf exodus in the globular star cluster 47 Tucanae, a dense swarm of hundreds of thousands of stars in our Milky Way galaxy. The cluster resides 16,700 light-years away in the southern constellation Tucana.

    1
    Globular cluster 47 Tucanae (also known as NGC 104). Photo taken by the Southern African Large
    Telescope
    (SALT)

    SALT South African Large Telescope
    SALT

    “We’ve seen the final picture before: white dwarfs that have already sorted themselves out and are orbiting in a location outside the core that is appropriate for their mass,” explained Jeremy Heyl of the University of British Columbia (UBC), Vancouver, Canada, first author on the science paper. The team’s results appeared in the May 1 issue of The Astrophysical Journal.

    “But in this study, which comprises about a quarter of all the young white dwarfs in the cluster, we’re actually catching the stars in the process of moving outward and segregating themselves according to mass,” Heyl said. “The entire process doesn’t take very long, only a few hundreds of millions of years, out of the 10-billion-year age of the cluster, for the white dwarfs to reach their new home in the outer suburbs.”

    “This result hasn’t been seen before, and it challenges some ideas about some of the details of how and when a star loses its mass near the end of its life,” added team member Harvey Richer of UBC.

    Using the ultraviolet-light capabilities of Hubble’s sharp-eyed Wide Field Camera 3 [WFC3], the astronomers examined 3,000 white dwarfs, tracing two populations with diverse ages and orbits.

    NASA Hubble WFC3
    WFC3

    One grouping was 6 million years old and had just begun their journey. Another was around 100 million years old and had already arrived at its new homestead far away from the center, roughly 1.5 light-years, or nearly 9 trillion miles, away.

    Only Hubble can detect these stars because ultraviolet light is blocked by Earth’s atmosphere and therefore doesn’t reach ground-based telescopes. The astronomers estimated the white dwarfs’ ages by analyzing their colors, which gives them the stars’ temperatures. The hottest dwarfs shine fiercely in ultraviolet light.

    The dwarfs were tossed out of the rough-and-tumble cluster center due to gravitational interactions with heftier stars orbiting the region. Stars in globular clusters sort themselves out by weight, with the heavier stars sinking to the middle. Before flaming out as white dwarfs, the migrating stars were among the most massive in the cluster, weighing roughly as much as our Sun. The more massive stars burned out long ago.

    The migrating white dwarfs, however, are not in a hurry to leave. Their orbits expand outward at about 30 miles an hour, roughly the average speed of a car traveling in the city. The dead stars will continue this pace for about 40 million years, until they reach a location that is more appropriate for their mass.

    Although the astronomers were not surprised to see the migration, they were puzzled to find that the youngest white dwarfs were just embarking on their journey. This discovery may be evidence that the stars shed much of their mass at a later stage in their lives than once thought.

    About 100 million years before stars evolve into white dwarfs, they swell up and become red giant stars. Many astronomers thought that stars lose most of their mass during this phase by blowing it off into space. But the Hubble observations reveal that the stars actually dump 40 percent to 50 percent of their bulk just 10 million years before completely burning out as white dwarfs.

    “This late start is evidence that these white dwarfs are losing a large amount of mass just before they become white dwarfs and not during the earlier red giant phase, as most astronomers had thought,” said Richer. “That’s why we are seeing stars still in the process of moving slowly away from the center of the cluster. It’s only after they lose their mass that they get gravitationally pushed out of the core. If the stars had shed most of their weight earlier in their lives, we wouldn’t see such a dramatic effect between the youngest white dwarfs and the older ones that are 100 million years old.”

    Although the white dwarfs have exhausted the hydrogen fuel that makes them shine as stars, these stellar relics are among the brightest stars in this primordial cluster because their brilliant hot cores have been exposed, which are luminous largely in ultraviolet light. “When a white dwarf forms, they’ve got all this stored-up heat in their cores, and the reason we can see a white dwarf is because over time they radiate their stored thermal energy slowly into space,” Richer explained. “They’re getting cooler and less luminous as time goes on because they have no nuclear sources of energy.”

    After making it through the gauntlet of gravitational interactions within the crowded 1.5-light-year-wide core, the traveling white dwarfs encounter few interactions as they migrate outward, because the density of stars decreases. “A lot of action happens when they’re 30 million to 40 million years old, and continues up to around 100 million years, and then as they get older the white dwarfs still evolve but less dramatically,” Heyl said.

    The 47 Tucanae cluster is an ideal place to study the mass segregation of white dwarfs because it is nearby and has a significant number of centrally concentrated stars that can be resolved by Hubble’s crisp vision.

    See the full article here.

    Please help promote STEM in your local schools.

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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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  • richardmitnick 7:39 am on May 12, 2015 Permalink | Reply
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    From Hubble: “NASA’s Great Observatories Celebrate International Year of Astronomy” old but worth it. 

    NASA Hubble Telescope

    Hubble

    November 10, 2009
    CONTACT

    Donna Weaver / Ray Villard
    Space Telescope Science Institute, Baltimore, Md.
    410-338-4493 / 410-338-4514
    dweaver@stsci.edu / villard@stsci.edu

    Whitney Clavin
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-4673
    whitney.clavin@jpl.nasa.gov

    Megan Watzke
    Chandra X-ray Center, Cambridge, Mass.
    617-496-7998
    mwatzke@cfa.harvard.edu

    A never-before-seen view of the turbulent heart of our Milky Way galaxy is being unveiled by NASA on Nov. 10. This event will commemorate the 400 years since Galileo first turned his telescope to the heavens in 1609.

    1
    In celebration of the International Year of Astronomy 2009, NASA’s Great Observatories — the Hubble Space Telescope, the Spitzer Space Telescope, and the Chandra X-ray Observatory — have collaborated to produce an unprecedented image of the central region of our Milky Way galaxy.

    In this spectacular image, observations using infrared light and X-ray light see through the obscuring dust and reveal the intense activity near the galactic core. Note that the center of the galaxy is located within the bright white region to the right of and just below the middle of the image. The entire image width covers about one-half a degree, about the same angular width as the full moon.

    Each telescope’s contribution is presented in a different color:

    • Yellow represents the near-infrared observations of Hubble. These observations outline the energetic regions where stars are being born as well as reveal hundreds of thousands of stars.
    • Red represents the infrared observations of Spitzer.

    NASA Spitzer Telescope
    Spitzer

    The radiation and winds from stars create glowing dust clouds that exhibit complex structures from compact, spherical globules to long, stringy filaments.

    • Blue and violet represent the X-ray observations of Chandra.

    NASA Chandra Telescope
    Chandra

    X-rays are emitted by gas heated to millions of degrees by stellar explosions and by outflows from the supermassive black hole in the galaxy’s center. The bright blue blob on the left side is emission from a double star system containing either a neutron star or a black hole.

    When these views are brought together, this composite image provides one of the most detailed views ever of our galaxy’s mysterious core.

    In celebration of this International Year of Astronomy, NASA is releasing images of the galactic center region as seen by its Great Observatories to more than 150 planetariums, museums, nature centers, libraries, and schools across the country.

    The sites will unveil a giant, 6-foot-by-3-foot print of the bustling hub of our galaxy that combines a near-infrared view from the Hubble Space Telescope, an infrared view from the Spitzer Space Telescope, and an X-ray view from the Chandra X-ray Observatory into one multiwavelength picture. Experts from all three observatories carefully assembled the final image from large mosaic photo surveys taken by each telescope. This composite image provides one of the most detailed views ever of our galaxy’s mysterious core.

    Participating institutions also will display a matched trio of Hubble, Spitzer, and Chandra images of the Milky Way’s center on a second large panel measuring 3 feet by 4 feet. Each image shows the telescope’s different wavelength view of the galactic center region, illustrating not only the unique science each observatory conducts, but also how far astronomy has come since Galileo.

    The composite image features the spectacle of stellar evolution: from vibrant regions of star birth, to young hot stars, to old cool stars, to seething remnants of stellar death called black holes. This activity occurs against a fiery backdrop in the crowded, hostile environment of the galaxy’s core, the center of which is dominated by a supermassive black hole nearly four million times more massive than our Sun. Permeating the region is a diffuse blue haze of X-ray light from gas that has been heated to millions of degrees by outflows from the supermassive black hole as well as by winds from massive stars and by stellar explosions. Infrared light reveals more than a hundred thousand stars along with glowing dust clouds that create complex structures including compact globules, long filaments, and finger-like “pillars of creation,” where newborn stars are just beginning to break out of their dark, dusty cocoons.

    The unveilings will take place at 152 institutions nationwide, reaching both big cities and small towns. Each institution will conduct an unveiling celebration involving the public, schools, and local media.

    The Astrophysics Division of NASA’s Science Mission Directorate supports the International Year of Astronomy Great Observatories image unveiling. The project is a collaboration among the Space Telescope Science Institute in Baltimore, Md., the Spitzer Science Center in Pasadena, Calif., and the Chandra X-ray Center in Cambridge, Mass.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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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  • richardmitnick 3:26 pm on May 7, 2015 Permalink | Reply
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    From Hubble: “Hubble Finds Giant Halo Around the Andromeda Galaxy” 

    NASA Hubble Telescope

    Hubble

    May 7, 2015
    CONTACT
    Ann Jenkins / Ray Villard
    Space Telescope Science Institute, Baltimore, Md.
    410-338-4488 / 410-338-4514
    jenkins@stsci.edu / villard@stsci.edu

    Felicia Chou
    NASA Headquarters, Washington, D.C.
    202-358-0257
    felicia.chou@nasa.gov

    Nicolas Lehner
    University of Notre Dame, Notre Dame, Indiana
    574-631-5755
    nlehner@nd.edu

    1

    Scientists using NASA’s Hubble Space Telescope have discovered that the immense halo of gas enveloping the Andromeda galaxy, our nearest massive galactic neighbor, is about six times larger and 1,000 times more massive than previously measured. The dark, nearly invisible halo stretches about a million light-years from its host galaxy, halfway to our own Milky Way galaxy. This finding promises to tell astronomers more about the evolution and structure of majestic giant spirals, one of the most common types of galaxies in the universe.

    “Halos are the gaseous atmospheres of galaxies. The properties of these gaseous halos control the rate at which stars form in galaxies according to models of galaxy formation,” explained the lead investigator, Nicolas Lehner of the University of Notre Dame, Indiana. The gargantuan halo is estimated to contain half the mass of the stars in the Andromeda galaxy itself, in the form of a hot, diffuse gas. If it could be viewed with the naked eye, the halo would be 100 times the diameter of the full Moon in the sky. This is equivalent to the patch of sky covered by two basketballs held at arm’s length.

    The Andromeda galaxy, also known as M31, lies 2.5 million light-years away and looks like a faint spindle, about 6 times the diameter of the full Moon. It is considered a near-twin to the Milky Way galaxy.

    2
    Andromeda Galaxy. Adam Evans

    Because the gas in Andromeda’s halo is dark, the team looked at bright background objects through the gas and observed how the light changed. This is a bit like looking at a glowing light at the bottom of a pool at night. The ideal background “lights” for such a study are quasars, which are very distant bright cores of active galaxies powered by black holes. The team used 18 quasars residing far behind Andromeda to probe how material is distributed well beyond the visible disk of the galaxy. Their findings were published in the May 10, 2015, edition of The Astrophysical Journal.

    Earlier research from Hubble’s Cosmic Origins Spectrograph (COS)-Halos program studied 44 distant galaxies and found halos like Andromeda’s, but never before has such a massive halo been seen in a neighboring galaxy. Because the previously studied galaxies were much farther away, they appeared much smaller on the sky. Only one quasar could be detected behind each faraway galaxy, providing only one light anchor point to map their halo size and structure. With its close proximity to Earth and its correspondingly large footprint on the sky, Andromeda provides a far more extensive sampling of a lot of background quasars.

    “As the light from the quasars travels toward Hubble, the halo’s gas will absorb some of that light and make the quasar appear a little darker in just a very small wavelength range,” explains co-investigator J. Christopher Howk, also of Notre Dame. “By measuring the dip in brightness in that range, we can tell how much halo gas from M31 there is between us and that quasar.”

    The scientists used Hubble’s unique capability to study the ultraviolet light from the quasars. Ultraviolet light is absorbed by Earth’s atmosphere, which makes it difficult to observe with a ground-based telescope. The team drew from about 5 years’ worth of observations stored in the Hubble data archive to conduct this research. Many previous Hubble campaigns have used quasars to study gas much farther away than — but in the general direction of — Andromeda, so a treasure trove of data already existed.

    But where did the giant halo come from? Large-scale simulations of galaxies suggest that the halo formed at the same time as the rest of Andromeda. The team also determined that it is enriched in elements much heavier than hydrogen and helium, and the only way to get these heavy elements is from exploding stars called supernovae. The supernovae erupt in Andromeda’s star-filled disk and violently blow these heavier elements far out into space. Over Andromeda’s lifetime, nearly half of all the heavy elements made by its stars have been expelled far beyond the galaxy’s 200,000-light-year-diameter stellar disk.

    What does this mean for our own galaxy? Because we live inside the Milky Way, scientists cannot determine whether or not such an equally massive and extended halo exists around our galaxy. It’s a case of not being able to see the forest for the trees. If the Milky Way does possess a similarly huge halo, the two galaxies’ halos may be nearly touching already and quiescently merging long before the two massive galaxies collide. Hubble observations indicate that the Andromeda and Milky Way galaxies will merge to form a giant elliptical galaxy beginning about 4 billion years from now.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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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  • richardmitnick 3:02 pm on May 7, 2015 Permalink | Reply
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    From ALMA: “ALMA Discovers Proto Super Star Cluster — a Cosmic ‘Dinosaur Egg’ About to Hatch” 

    ESO ALMA Array
    ALMA

    07 May 2015
    Valeria Foncea
    Education and Public Outreach Officer
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 467 6258
    Cell: +56 9 75871963
    Email: vfoncea@alma.cl

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory
    Charlottesville, Virginia, USA
    Tel: +1 434 296 0314
    Cell: +1 434.242.9559
    E-mail: cblue@nrao.edu

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

    Masaaki Hiramatsu
    Education and Public Outreach Officer, NAOJ Chile
    Observatory Tokyo, Japan
    Tel: +81 422 34 3630
    E-mail: hiramatsu.masaaki@nao.ac.jp

    1
    The Antennae galaxies, shown in visible light in a Hubble image (upper image), were studied with ALMA, revealing extensive clouds of molecular gas (center right image). One cloud (bottom image) is incredibly dense and massive, yet apparently star free, suggesting it is the first example of a prenatal globular cluster ever identified. Credit: NASA/ESA Hubble, B. Whitmore (STScI); K. Johnson, U.Va.; ALMA (NRAO/ESO/NAOJ); B. Saxton (NRAO/AUI/NSF).

    NASA Hubble Telescope
    NASA/ESA Hubble

    NRAO VLA
    NRAO/VLA

    Globular clusters – dazzling agglomerations of up to a million ancient stars – are among the oldest objects in the universe. Though plentiful in and around many galaxies, newborn examples are vanishingly rare and the conditions necessary to create new ones have never been detected, until now.

    Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have discovered what may be the first known example of a globular cluster about to be born: an incredibly massive, extremely dense, yet star-free cloud of molecular gas.

    “We may be witnessing one of the most ancient and extreme modes of star formation in the universe,” said Kelsey Johnson, an astronomer at the University of Virginia in Charlottesville and lead author on a paper accepted for publication in the Astrophysical Journal. “This remarkable object looks like it was plucked straight out of the very early universe. To discover something that has all the characteristics of a globular cluster, yet has not begun making stars, is like finding a dinosaur egg that’s about to hatch.”

    This object, which the astronomers playfully refer to as the “Firecracker,” is located approximately 50 million light-years away from Earth nestled inside a famous pair of interacting galaxies (NGC 4038 and NGC 4039), which are collectively known as the Antennae galaxies. The tidal forces generated by their ongoing merger are triggering star formation on a colossal scale, much of it occurring inside dense clusters.

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    NGC 4038 (left) and NGC 4039 (right)

    What makes the Firecracker unique, however, is its extraordinary mass, comparatively small size, and apparent lack of stars.

    All other globular cluster analogues astronomers have observed to date are already brimming with stars. The heat and radiation from these stars have therefore altered the surrounding environment considerably, erasing any evidence of its colder, quieter beginnings.

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    ALMA image of dense cores of molecular gas in the Antennae galaxies. The round yellow object near the center may be the first prenatal example of a globular cluster ever identified. It is surrounded by a giant molecular cloud. Credit: K. Johnson, U.Va.; ALMA (NRAO/ESO/NAOJ).

    With ALMA, the astronomers were able to find and study in detail a pristine example of such an object before stars forever change its unique characteristics. This afforded astronomers a first-ever glimpse of the conditions that may have led to the formation of many, if not all globular clusters.

    “Until now, clouds with this potential have only been seen as teenagers, after star formation had begun,” said Johnson. “That meant that the nursery had already been disturbed. To understand how a globular cluster forms, you need to see its true beginnings.”

    Most globular clusters formed during a veritable “baby boom” around 12 billion years ago, at a time when galaxies first assembled. Each contains as many as a million densely packed “second generation” stars — stars with conspicuously low concentrations of heavy metals, indicating they formed very early in the history of the universe. Our own Milky Way is known to have at least 150 such clusters, though it may have many more.

    Throughout the universe, star clusters of various sizes are still forming to this day. It’s possible, though increasingly rare, that the largest and densest of these will go on to become globular clusters.

    “The survival rate for a massive young star cluster to remain intact is very low – around one percent,” said Johnson. “Various external and internal forces pull these objects apart, either forming open clusters like the Pleiades or completely disintegrating to become part of a galaxy’s halo.”

    The astronomers believe, however, that the object they observed with ALMA, which contains 50 million times the mass of the Sun in molecular gas, is sufficiently dense that it has a good chance of being one of the lucky ones.


    Animation of ALMA data depicting dense cores of molecular gas in the Antennae galaxies. The yellow object at the center may be the first prenatal example of a globular cluster ever identified. Credit: K. Johnson, U.Va.; ALMA (NRAO/ESO/NAOJ)

    Globular clusters evolve out of their embryonic, star-free stage very rapidly — in as little as one million years. This means the object discovered by ALMA is undergoing a very special phase of its life, offering astronomers a unique opportunity to study a major component of the early universe.

    The ALMA data also indicate that the Firecracker cloud is under extreme pressure – approximately 10,000 times greater than typical interstellar pressures. This supports previous theories that high pressures are required to form globular clusters.

    In exploring the Antennae, Johnson and her colleagues observed the faint emission from carbon monoxide molecules, which allowed them to image and characterize individual clouds of dust and gas. The lack of any appreciable thermal emission – the telltale signal given off by gas heated by nearby stars – confirms that this newly discovered object is still in its pristine, unaltered state.

    Further studies with ALMA may reveal additional examples of proto super star clusters in the Antennae galaxies and other interacting galaxies, shedding light on the origins of these ancient objects and the role they play in galactic evolution.

    More Information

    The paper The Physical Conditions in a Pre Super Star Cluster Molecular Cloud in the Antennae Galaxies by K.E. Johnson et.al it can be found here.

    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 2:31 pm on May 4, 2015 Permalink | Reply
    Tags: , , NASA/ESA Hubble   

    From Hubble: “The peculiar asymmetry of NGC 949″ 

    NASA Hubble Telescope

    Hubble

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    Credit: NASA/ESA Hubble

    This image provides the clearest ever view of galaxy NGC 949, which lies over 30 million light-years away in the constellation of Triangulum. The galaxy has an unusual shape, made more obscure due to its inclination. From our point of view, it is difficult to discern exactly what type of galaxy NGC 949 is, but it is certainly a disc galaxy of some kind, most likely a spiral.

    NGC 949 was first discovered by Sir William Herschel on 21 September 1786, using an 18.7-inch reflecting telescope. The galaxy was one of about 3000 objects Herschel catalogued as “nebulae” during an intense and systematic deep sky survey, the results of which eventually formed the bulk of the New General Catalogue (NGC).

    Taken with Hubble’s Advanced Camera for Surveys (ACS), this new image shows extraordinary detail.

    NASA Hubble ACS
    ACS

    This detail allows us to see a strange asymmetric alignment in the dark lanes of dust that snake across the galaxy. The top-right half of the galaxy appears considerably more marbled with dust in this image; a curious observation explained by stars tending to favour locations towards the centre of a galaxy, and dust preferring almost invariably to reside along the galactic plane.

    When a galaxy is inclined as NGC 949 is, some regions — in this case the top-right — are tipped towards us and the light from the stars we see in these regions has had to travel through more dust. This causes the light to appear redder — the result of the same process that gives the sun’s light a red hue at dusk — or else disappear entirely, making the dust appear more prominent on that side of the galaxy.

    In the part tipped away from us, the light from the stars has had to pass through much less dust to reach us, so it appears brighter, and the dust is much less prominent.

    Were it possible to view NGC 949 from the opposite side, the apparent alignment of the dust would be reversed.

    The scientific advantages of this effect were recently displayed in suitably stunning style in the M31 PHAT mosaic, which allowed astronomers to produce a partial three-dimensional dust map of M31 four times clearer than any previously attempted.

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    M31 PHAT Mosaic
    Credits: NASA, ESA, J. Dalcanton (University of Washington), the PHAT team, R. Gendler

    See the full article here.

    Please help promote STEM in your local schools.

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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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  • richardmitnick 2:13 pm on April 25, 2015 Permalink | Reply
    Tags: , , NASA/ESA Hubble   

    From NOVA: “Invisible Universe Revealed”- The Story of the Hubble Space Telescope 

    PBS NOVA

    NOVA

    Apr 25, 2015

    25 years ago, NASA launched one of the most ambitious experiments in the history of astronomy: the Hubble Space Telescope. In honor of Hubble’s landmark anniversary, this show tells the remarkable story of the telescope that forever changed our understanding of the cosmos and our place in it. But amazingly, when the telescope first sent images back to earth, it seemed that the entire project was a massive failure; a one-millimeter engineering blunder had turned the billion-dollar telescope into an object of ridicule. It fell to five heroic astronauts in a daring mission to return Hubble to the cutting edge of science. Hear from the scientists and engineers on the front line who tell the amazing Hubble story as never before. This single telescope has helped astronomers pinpoint the age of the universe, revealed the birthplace of stars and planets, advanced our understanding of dark energy and cosmic expansion, and uncovered black holes lurking at the heart of galaxies. For more than a generation, Hubble’s stunning images have brought the beauty of the heavens to millions, revealing a cosmos richer and more wondrous than we ever imagined. Enjoy the story of this magnificent machine and its astonishing discoveries.

    See the full article here.

    Please help promote STEM in your local schools.

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    NOVA is the highest rated science series on television and the most watched documentary series on public television. It is also one of television’s most acclaimed series, having won every major television award, most of them many times over.

     
  • richardmitnick 3:38 pm on April 24, 2015 Permalink | Reply
    Tags: , , NASA/ESA Hubble   

    From Hubble: The 25th Anniversary Image – Hubblecast 82 

    NASA Hubble Telescope

    Hubble

    This Hubblecast explores the new image of star cluster Westerlund 2, taken by the NASA/ESA Hubble Space telescope and released to celebrate its 25th year in orbit.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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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