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  • richardmitnick 7:01 am on June 24, 2015 Permalink | Reply
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    From Chandra: “Circinus X-1: X-ray Echoes Pinpoint Location of Distant Flaring Neutron Star” 

    NASA Chandra

    June 23, 2015

    1
    Composite

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    X-ray

    3
    Optical
    Credit X-ray: NASA/CXC/Univ. of Wisconsin-Madison/S.Heinz et al; Optical: DSS
    Release Date June 23, 2015

    Light echoes around a neutron star have allowed a precise distance to be determined to it. These light echoes are produced when a burst of X-rays bounces off of clouds. Determining distances in astronomy is notoriously difficult so objects like this are valuable. The new distance measurement to Circinus X-1 is over twice that of one previously published value.

    Data from NASA’s Chandra X-ray Observatory has helped provide a rare opportunity to determine the distance to an object on the other side of the Milky Way galaxy, as described in our latest press release.

    The object is Circinus X-1, containing a neutron star – the collapsed core left behind after a star exploded – in orbit with a massive star. The Chandra data reveal a set of four rings that appear as circles around Circinus X-1. These rings can be seen in the composite image where X-rays from Chandra are red, green, and blue corresponding to low, medium, and high-energy X-rays respectively, which have been combined with a view in visible light from the Digitized Sky Survey*. The sharp edges are caused by the large size of the X-ray rings compared to the relatively small field-of-view of the Chandra detectors, providing only partial coverage.

    What are these rings and what information do they provide? These rings are light echoes, similar to sound echoes that we may experience here on Earth. Instead of sound waves bouncing off a canyon wall, the echoes around Circinus X-1 are produced when a burst of X-rays from the star system ricochet off of clouds of dust between Circinus X-1 and Earth.

    4
    This artist’s illustration shows in detail how the ringed structure seen by Chandra is produced. Each ring is caused by X-rays from the Circinus X-1 flare bouncing off of different dust clouds. If the cloud is closer to us, the ring appears to be larger. The result, as seen by Chandra, is a set of concentric rings with different apparent sizes depending on the distance of the intervening cloud from us. The physical sizes of the rings, using the labels given the illustration, are 41 light years (ring a), 49 light years (ring b), 55 light years (ring c), and 52 light years (ring d).

    By combining the light echoes that Chandra detects with radio data from the Mopra radio telescope in Australia, which determined the distance to the intervening clouds, astronomers can estimate the distance to Circinus X-1 using relatively simple geometry.

    CSIRO ATNF Mopra Telescope
    MOPRA

    The light echo method generates a distance of 30,700 light years. The observation thus settles a large difference amongst previous results, one similar to this work and one indicating a much smaller distance of about 13,000 light years.

    Such a difference in distance estimate to Circinus X-1 would have implications for other properties that have been observed before in the system. For example, if it is over twice as far away as some have previously thought, then this means its light output is much greater. (Consider a light bulb that is moved farther away, it will appear dimmer.) Because Circinus X-1 has been known to flare strongly in X-ray light, including an outburst in 2013, this implies that the system has exceeded the so-called Eddington Limit. This threshold, which is the balance between the inward pull of gravity and the outward push of radiation from an object, is generally only exceeded by systems containing black holes, not neutron stars.

    The researchers also determined that the speed of the jet of high-energy particles produced by the system is at least 99.9% of the speed of light. This extreme velocity is usually associated with jets produced by a black hole.

    These results appear in an upcoming issue of The Astrophysical Journal and are available online.

    • The writer does not make clear whether the DSS referenced is from STScI or ESO.

    See the full article here.

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

     
  • richardmitnick 3:23 pm on June 10, 2015 Permalink | Reply
    Tags: , NASA Chandra,   

    From Chandra: “NGC 5813: Chandra Finds Evidence for Serial Black Hole Eruptions” 

    NASA Chandra

    June 10, 2015

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    Composite

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    X-ray

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    Optical
    Credit X-ray: NASA/CXC/SAO/S.Randall et al., Optical: SDSS
    Release Date June 10, 2015

    -Chandra data show the supermassive black hole at the center of NGC 5813 has erupted multiple times over 50 million years.
    -NGC 5813 is a group of galaxies that is immersed in an enormous reservoir of hot gas.
    -Cavities, or bubbles, in the hot gas that Chandra detects gives information about the black hole’s eruptions.
    -Chandra’s observations of NGC 5813 are the longest ever of a galaxy group taken in X-ray light.

    Astronomers have used NASA’s Chandra X-ray Observatory to show that multiple eruptions from a supermassive black hole over 50 million years have rearranged the cosmic landscape at the center of a group of galaxies.

    Scientists discovered this history of black hole eruptions by studying NGC 5813, a group of galaxies about 105 million light years [1 light year = about 6 trillion miles] from Earth. These Chandra observations are the longest ever obtained of a galaxy group, lasting for just over a week. The Chandra data are shown in this new composite image where the X-rays from Chandra (purple) have been combined with visible light data (red, green and blue).

    Galaxy groups are like their larger cousins, galaxy clusters, but instead of containing hundreds or even thousands of galaxies like clusters do, galaxy groups are typically comprised of 50 or fewer galaxies. Like galaxy clusters, groups of galaxies are enveloped by giant amounts of hot gas that emit X-rays.

    Local Group
    Milky Way’s Local [Galaxy] Group

    The erupting supermassive black hole is located in the central galaxy of NGC 5813. The black hole’s spin, coupled with gas spiraling toward the black hole, can produce a rotating, tightly wound vertical tower of magnetic field that flings a large fraction of the inflowing gas away from the vicinity of the black hole in an energetic, high-speed jet.

    The researchers were able to determine the length of the black hole’s eruptions by studying cavities, or giant bubbles, in the multi-million degree gas in NGC 5813. These cavities are carved out when jets from the supermassive black hole generate shock waves that push the gas outward and create huge holes.

    The latest Chandra observations reveal a third pair of cavities in addition to two that were previously found in NGC 5813, representing three distinct eruptions from the central black hole. (Mouse over the image for annotations of the cavities.) This is the highest number of pairs of cavities ever discovered in either a group or a cluster of galaxies. Similar to how a low-density bubble of air will rise to the surface in water, the giant cavities in NGC 5813 become buoyant and move away from the black hole.

    To understand more about the black hole’s history of eruptions, the researchers studied the details of the three pairs of cavities. They found that the amount of energy required to create the pair of cavities closest to the black hole is lower than the energy that produced the older two pairs. However, the rate of energy production, or power, is about the same for all three pairs. This indicates that the eruption associated with the inner pair of cavities is still occurring.

    Each of the three pairs of cavities is associated with a shock front, visible as sharp edges in the X-ray image. These shock fronts, akin to sonic booms for a supersonic plane, heat the gas, preventing most of it from cooling and forming large numbers of new stars.

    Close study of the shock fronts reveals that they are actually slightly broadened, or blurred, rather than being very sharp. This may be caused by turbulence in the hot gas. Assuming this is the case, the authors found a turbulent velocity – that is, the average speed of random motions of the gas – of about 160,000 miles per hour (258,000 kilometers per hour). This is consistent with the predictions of theoretical models and estimates based on X-ray observations of the hot gas in other groups and clusters.

    A paper describing these results was published in the June 1st, 2015 issue of The Astrophysical Journal and is available online. The first author is Scott Randall from the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, MA and the co-authors are Paul Nulsen, Christine Jones, William Forman and Esra Bulbul from CfA; Tracey Clarke from the Naval Research Laboratory in Washington DC; Ralph Kraft from CfA; Elizabeth Blanton from Boston University in Boston, MA; Lawrence David from CfA; Norbert Werner from Stanford University in Stanford, CA; Ming Sun from University of Alabama in Huntsville, AL; Megan Donahue from Michigan State University in East Lansing, MI; Simona Giacintucci from University of Maryland in College Park, MD and Aurora Simionescu from the Japan Aerospace Exploration Agency in Kanagawa, Japan.

    See the full article here.

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

     
  • richardmitnick 11:02 am on May 28, 2015 Permalink | Reply
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    From Chandra: “Space-time Foam: NASA Telescopes Set Limits on Space-time Quantum Foam” 

    NASA Chandra

    May 28, 2015

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    Credit NASA/CXC/FIT/E.Perlman et al, Illustration: NASA/CXC/M.Weiss
    Release Date May 28, 2015

    Fast Facts for BR 0353-3820:
    Credit NASA/CXC/FIT/E.Perlman et al, Illustration: NASA/CXC/M.Weiss
    Release Date May 28, 2015

    Fast Facts for BR 0418-5723:
    Credit NASA/CXC/FIT/E.Perlman et al, Illustration: NASA/CXC/M.Weiss
    Release Date May 28, 2015

    Fast Facts for BR 0424-2209:
    Credit NASA/CXC/FIT/E.Perlman et al
    Release Date May 28, 2015

    Fast Facts for PSS 0747+4434:
    Credit NASA/CXC/FIT/E.Perlman et al, Illustration: NASA/CXC/M.Weiss
    Release Date May 28, 2015

    Fast Facts for PSS 1058+1245:
    Credit NASA/CXC/FIT/E.Perlman et al, Illustration: NASA/CXC/M.Weiss
    Release Date May 28, 2015

    X-ray and gamma-ray observations of distant quasars are being used to test space-time at extremely tiny scales.

    Certain models predict tiny bubbles quadrillions of times smaller than the nucleus of an atom exist.

    This “space-time foam” is impossible to observe directly so scientists use other methods to test ideas about it.

    A new study combining data from NASA’s Chandra X-ray Observatory and Fermi Gamma-ray Telescope, and the Very Energetic Radiation Imaging Telescope Array (VERITAS) in Arizona is helping scientists set limits on the quantum nature of space-time on extremely tiny scales, as explained in our latest press release.

    NASA Fermi Telescope
    Fermi

    NASA VERITAS
    VERITAS

    Certain aspects of quantum mechanics predict that space-time – the three dimensions of space plus time — would not be smooth on the scale of about ten times a billionth of a trillionth of the diameter of a hydrogen atom’s nucleus. They refer to the structure that may exist at this extremely small size as “space-time foam.” This artist’s illustration depicts how the foamy structure of space-time may appear, showing tiny bubbles quadrillions of times smaller than the nucleus of an atom that are constantly fluctuating and last for only infinitesimal fractions of a second.

    Because space-time foam is so small, it is impossible to observe it directly. However, depending on what model of space-time is used, light that has traveled over great cosmic distances may be affected by the unseen foam in ways that scientists can analyze. More specifically, some models predict that the accumulation of distance uncertainties for light traveling across billions of light years would cause the image quality to degrade so much that the objects would become undetectable. The wavelength where the image disappears should depend on the model of space-time foam used.

    The researchers used observations of X-rays and gamma-rays from very distant quasars – luminous sources produced by matter falling towards supermassive black holes – to test models of the smoothness and structure of space-time. Chandra’s X-ray detection of six quasars, shown in the upper part of the graphic, at distances of billions of light years, rules out one model, according to which photons diffuse randomly through space-time foam in a manner similar to light diffusing through fog. Detections of distant quasars at shorter, gamma-ray wavelengths with Fermi and even shorter wavelengths with VERITAS demonstrate that a second, so-called holographic model with less diffusion does not work.

    These results appeared in the May 20th issue of The Astrophysical Journal and are available online. The authors of this study are Eric Perlman (Florida Institute of Technology), Saul Rappaport (Massachusetts Institute of Technology), Wayne Christensen (University of North Carolina), Y. Jack Ng (University of North Carolina), John DeVore (Visidyne), and David Pooley (Sam Houston State University).

    See the full article here.

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

     
  • richardmitnick 3:16 pm on May 14, 2015 Permalink | Reply
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    From Chandra: “Magnetar Near Supermassive Black Hole Delivers Surprises” 

    NASA Chandra

    May 13, 2015
    Janet Anderson
    Marshall Space Flight Center, Huntsville, Ala.
    256-544-0034
    janet.l.anderson@nasa.gov

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

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    Credit NASA/CXC/INAF/F.Coti Zelati et al
    Release Date May 14, 2015

    A magnetar near the Milky Way’s supermassive black hole is exhibiting some unusual behavior.

    Since its discovery in 2013, this magnetar has been monitored by Chandra and XMM-Newton.

    The X-ray output from this magnetar is dropping more slowly than others and its surface is exceptionally hot.

    In 2013, astronomers announced they had discovered a magnetar exceptionally close to the supermassive black hole at the center of the Milky Way using a suite of space-borne telescopes including NASA’s Chandra X-ray Observatory.

    Magnetars are dense, collapsed stars (called “neutron stars“) that possess enormously powerful magnetic fields. At a distance that could be as small as 0.3 light years (or about 2 trillion miles) from the 4-million-solar mass black hole in the center of our Milky Way galaxy, the magnetar is by far the closest neutron star to a supermassive black hole ever discovered and is likely in its gravitational grip.

    Since its discovery two years ago when it gave off a burst of X-rays, astronomers have been actively monitoring the magnetar, dubbed SGR 1745-2900, with Chandra and the European Space Agency’s XMM-Newton.

    ESA XMM Newton
    ESA/XMM-Newton

    The main image of the graphic shows the region around the Milky Way’s black hole in X-rays from Chandra (red, green, and blue are the low, medium, and high-energy X-rays respectively). The inset contains Chandra’s close-up look at the area right around the black hole, showing a combined image obtained between 2005 and 2008 (left) when the magnetar was not detected, during a quiescent period, and an observation in 2013 (right) when it was caught as a bright point source during the X-ray outburst that led to its discovery.

    A new study uses long-term monitoring observations to reveal that the amount of X-rays from SGR 1745-2900 is dropping more slowly than other previously observed magnetars, and its surface is hotter than expected.

    The team first considered whether “starquakes” are able to explain this unusual behavior. When neutron stars, including magnetars, form, they can develop a tough crust on the outside of the condensed star. Occasionally, this outer crust will crack, similar to how the Earth’s surface can fracture during an earthquake. Although starquakes can explain the change in brightness and cooling seen in many magnetars, the authors found that this mechanism by itself was unable to explain the slow drop in X-ray brightness and the hot crustal temperature. Fading in X-ray brightness and surface cooling occur too quickly in the starquake model.

    The researchers suggest that bombardment of the surface of the magnetar by charged particles trapped in twisted bundles of magnetic fields above the surface may provide the additional heating of the magnetar’s surface, and account for the slow decline in X-rays. These twisted bundles of magnetic fields can be generated when the neutron star forms.

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    This illustration shows how an extremely rapidly rotating neutron star, which has formed from the collapse of a very massive star, can produce incredibly powerful magnetic fields. (Illustration: NASA/CXC/M.Weiss)

    The researchers do not think that the magnetar’s unusual behavior is caused by its proximity to a supermassive black hole, as the distance is still too great for strong interactions via magnetic fields or gravity.

    Astronomers will continue to study SGR 1745-2900 to glean more clues about what is happening with this magnetar as it orbits our galaxy’s supermassive black hole.

    These results appear in Monthly Notices of the Royal Astronomical Society in a paper led by the PhD student Francesco Coti Zelati (Universita’ dell’ Insubria, University of Amsterdam, INAF-OAB), within a large international collaboration including N. Rea (University of the Amsterdam, CSIC-IEEC), A. Papitto, D. Viganò (CSIC-IEEC), J. A. Pons (Universitat d’Alacant), R. Turolla (Universita’ di Padova, MSSL), P. Esposito (INAF, CfA), D. Haggard (Amherst college), F. K. Baganoff (MIT), G. Ponti (MPE), G. L. Israel, S. Campana (INAF), D. F. Torres (CSIC-IEEC, ICREA), A. Tiengo (IUSS, INAF), S. Mereghetti (INAF), R. Perna (Stony Brook University), S. Zane (MSSL), R. P. Mignani (INAF, University of Zielona Gora), A. Possenti, L. Stella (INAF).

    See the full article here.

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

     
    • kagmi 5:37 pm on May 14, 2015 Permalink | Reply

      Thanks for explaining about the colors in the images!

      I always wonder, looking at these telescopic images, how close to “true color” they are.

      You can often find images of the same nebula in a variety of color schemes depending on how they’re coding color, I presume, which makes me wonder if any of them are anything akin to “real color” or if many of these objects (like nebulae) are just too faint to be seen in any meaningful capacity by the naked eye, even from close-up.

      Like

    • richardmitnick 6:09 pm on May 14, 2015 Permalink | Reply

      I would love to take credit for the explanations. But I cannot. Everything I give you was in the article from the source. The link to the original article is near the bottom of every post.

      Thanks for all of your comments.

      Like

  • 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.

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    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.

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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 3:39 pm on May 1, 2015 Permalink | Reply
    Tags: , , NASA Chandra,   

    From Chandra: “NASA’s Chandra Suggests Black Holes Gorging at Excessive Rates” 

    NASA Chandra

    April 30, 2015
    Jennifer Harbaugh

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    Illustration: CXC/M. Weiss
    X-ray images: NASA/CXC/Penn State/B. Luo et al.

    A group of unusual giant black holes may be consuming excessive amounts of matter, according to a new study using NASA’s Chandra X-ray Observatory. This finding may help astronomers understand how the largest black holes were able to grow so rapidly in the early Universe.

    Astronomers have known for some time that supermassive black holes − with masses ranging from millions to billions of times the mass of the Sun and residing at the centers of galaxies − can gobble up huge quantities of gas and dust that have fallen into their gravitational pull. As the matter falls towards these black holes, it glows with such brilliance that they can be seen billions of light years away. Astronomers call these extremely ravenous black holes “quasars.”

    This new result suggests that some quasars are even more adept at devouring material than scientists previously knew.

    “Even for famously prodigious consumers of material, these huge black holes appear to be dining at enormous rates, at least five to ten times faster than typical quasars,” said Bin Luo of Penn State University in State College, Pennsylvania, who led the study.

    Luo and his colleagues examined data from Chandra for 51 quasars that are located at a distance between about 5 billion and 11.5 billion light years from Earth. These quasars were selected because they had unusually weak emission from certain atoms, especially carbon, at ultraviolet wavelengths. About 65% of the quasars in this new study were found to be much fainter in X-rays, by about 40 times on average, than typical quasars.

    The weak ultraviolet atomic emission and X-ray fluxes from these objects could be an important clue to the question of how a supermassive black hole pulls in matter. Computer simulations show that, at low inflow rates, matter swirls toward the black hole in a thin disk. However, if the rate of inflow is high, the disk can puff up dramatically, because of pressure from the high radiation, into a torus or donut that surrounds the inner part of the disk.

    “This picture fits with our data,” said co-author Jianfeng Wu of the Harvard-Smithsonian Center for Astrophysics, in Cambridge, Massachusetts. “If a quasar is embedded in a thick donut-shaped structure of gas and dust, the donut will absorb much of the radiation produced closer to the black hole and prevent it from striking gas located further out, resulting in weaker ultraviolet atomic emission and X-ray emission.”

    The usual balance between the inward pull of gravity and the outward pressure of radiation would also be affected.

    “More radiation would be emitted in a direction perpendicular to the thick disk, rather than along the disk, allowing material to fall in at higher rates,” said co-author Niel Brandt, also of Penn State University.

    The important implication is that these “thick-disk” quasars may harbor black holes growing at an extraordinarily rapid rate. The current study and previous ones by different teams suggest that such quasars might have been more common in the early Universe, only about a billion years after the Big Bang. Such rapid growth might also explain the existence of huge black holes at even earlier times.

    A paper describing these results appears in an upcoming issue of The Astrophysical Journal and is available online.

    Read More from NASA’s Chandra X-ray Observatory

    See the full article here.

    Please help promote STEM in your local schools.

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

     
  • richardmitnick 10:57 am on April 17, 2015 Permalink | Reply
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    From Chandra: “NGC 6388: White Dwarf May Have Shredded Passing Planet” 

    NASA Chandra

    April 16, 2015

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    Composite

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    X-ray

    3
    Optical
    Credit X-ray: NASA/CXC/IASF Palermo/M.Del Santo et al; Optical: NASA/STScI
    Release Date April 16, 2015

    A planet may have been ripped apart by a white dwarf star in the outskirts of the Milky Way.

    A white dwarf is the dense core of a star like the Sun that has run out of nuclear fuel.

    Combining data from Chandra and several other telescopes, researchers think a “tidal disruption” may explain what is observed.

    The destruction of a planet may sound like the stuff of science fiction, but a team of astronomers has found evidence that this may have happened in an ancient cluster of stars at the edge of the Milky Way galaxy.

    Using several telescopes, including NASA’s Chandra X-ray Observatory, researchers have found evidence that a white dwarf star – the dense core of a star like the Sun that has run out of nuclear fuel – may have ripped apart a planet as it came too close.

    How could a white dwarf star, which is only about the size of the Earth, be responsible for such an extreme act? The answer is gravity. When a star reaches its white dwarf stage, nearly all of the material from the star is packed inside a radius one hundredth that of the original star. This means that, for close encounters, the gravitational pull of the star and the associated tides, caused by the difference in gravity’s pull on the near and far side of the planet, are greatly enhanced. For example, the gravity at the surface of a white dwarf is over ten thousand times higher than the gravity at the surface of the Sun.

    Researchers used the European Space Agency’s INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) to discover a new X-ray source near the center of the globular cluster NGC 6388.

    ESA Integral
    ESA/INTEGRAL

    Optical observations had hinted that an intermediate-mass black hole with mass equal to several hundred Suns or more resides at the center of NGC 6388. The X-ray detection by INTEGRAL then raised the intriguing possibility that the X-rays were produced by hot gas swirling towards an intermediate-mass black hole.

    In a follow-up X-ray observation, Chandra’s excellent X-ray vision enabled the astronomers to determine that the X-rays from NGC 6388 were not coming from the putative black hole at the center of the cluster, but instead from a location slightly off to one side. A new composite image shows NGC 6388 with X-rays detected by Chandra in pink and visible light from the Hubble Space Telescope in red, green, and blue, with many of the stars appearing to be orange or white.

    NASA Hubble Telescope
    NASA/ESA Hubble

    Overlapping X-ray sources and stars near the center of the cluster also causes the image to appear white.

    With the central black hole ruled out as the potential X-ray source, the hunt continued for clues about the actual source in NGC 6388. The source was monitored with the X-ray telescope on board NASA’s Swift Gamma Ray Burst mission for about 200 days after the discovery by INTEGRAL.

    NASA SWIFT Telescope
    NASA/Swift

    The source became dimmer during the period of Swift observations. The rate at which the X-ray brightness dropped agrees with theoretical models of a disruption of a planet by the gravitational tidal forces of a white dwarf. In these models, a planet is first pulled away from its parent star by the gravity of the dense concentration of stars in a globular cluster. When such a planet passes too close to a white dwarf, it can be torn apart by the intense tidal forces of the white dwarf. The planetary debris is then heated and glows in X-rays as it falls onto the white dwarf. The observed amount of X-rays emitted at different energies agrees with expectations for a tidal disruption event.

    The researchers estimate that the destroyed planet would have contained about a third of the mass of Earth, while the white dwarf has about 1.4 times the Sun’s mass.

    While the case for the tidal disruption of a planet is not iron-clad, the argument for it was strengthened when astronomers used data from the multiple telescopes to help eliminate other possible explanations for the detected X-rays. For example, the source does not show some of the distinctive features of a binary containing a neutron star, such as pulsations or rapid X-ray bursts. Also, the source is much too faint in radio waves to be part of a binary system with a stellar-mass black hole.

    A paper describing these results was published in an October 2014 issue of the Monthly Notices of the Royal Astronomical Society. The first author is Melania Del Santo of the National Institute for Astrophysics (INAF), IASF-Palermo, Italy, and the co-authors are Achille Nucita of the Universitá del Salento in Lecce, Italy; Giuseppe Lodato of the Universitá Degli Studi di Milano in Milan, Italy; Luigi Manni and Francesco De Paolis of the Universitá del Salento in Lecce, Italy; Jay Farihi of University College London in London, UK; Giovanni De Cesare of the National Institute for Astrophysics in IAPS-Rome, Italy and Alberto Segreto of the National Institute for Astrophysics (INAF), IASF-Palermo, Italy.

    See the full article here.

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

     
  • richardmitnick 4:12 pm on March 16, 2015 Permalink | Reply
    Tags: , NASA Chandra   

    From Chandra: “GK Persei: “Mini Supernova” Explosion Could Have Big Impact” 

    NASA Chandra

    March 16, 2015

    GK Persei is a “classical nova,” an outburst produced by a thermonuclear explosion on the surface of a white dwarf star. Classical novas are considered to be miniature versions of supernova explosions. Astronomers used Chandra to observe differences in GK Persei over a span of nearly 14 years. A new image of GK Persei contains X-rays (blue), optical data (yellow), and radio data (pink).

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    Credit X-ray: NASA/CXC/RIKEN/D.Takei et al; Optical: NASA/STScI; Radio: NRAO/VLA
    Release Date March 16, 2015

    In Hollywood blockbusters, explosions are often among the stars of the show. In space, explosions of actual stars are a focus for scientists who hope to better understand their births, lives, and deaths and how they interact with their surroundings.

    Using NASA’s Chandra X-ray Observatory, astronomers have studied one particular explosion that may provide clues to the dynamics of other, much larger stellar eruptions.

    A team of researchers pointed the telescope at GK Persei, an object that became a sensation in the astronomical world in 1901 when it suddenly appeared as one of the brightest stars in the sky for a few days, before gradually fading away in brightness. Today, astronomers cite GK Persei as an example of a “classical nova,” an outburst produced by a thermonuclear explosion on the surface of a white dwarf star, the dense remnant of a Sun-like star.

    A nova can occur if the strong gravity of a white dwarf pulls material from its orbiting companion star. If enough material, mostly in the form of hydrogen gas, accumulates on the surface of the white dwarf, nuclear fusion reactions can occur and intensify, culminating into a cosmic-sized hydrogen bomb blast. The outer layers of the white dwarf are blown away, producing a nova outburst that can be observed for a period of months to years as the material expands into space.

    Classical novas can be considered to be “miniature” versions of supernova explosions. Supernovas signal the destruction of an entire star and can be so bright that they outshine the whole galaxy where they are found. Supernovas are extremely important for cosmic ecology because they inject huge amounts of energy into the interstellar gas, and are responsible for dispersing elements such as iron, calcium and oxygen into space where they may be incorporated into future generations of stars and planets.

    Although the remnants of supernovas are much more massive and energetic than classical novas, some of the fundamental physics is the same. Both involve an explosion and creation of a shock wave that travels at supersonic speeds through the surrounding gas.

    The more modest energies and masses associated with classical novas means that the remnants evolve more quickly. This, plus the much higher frequency of their occurrence compared to supenovas, makes classical novas important targets for studying cosmic explosions.

    Chandra first observed GK Persei in February 2000 and then again in November 2013. This 13-year baseline provides astronomers with enough time to notice important differences in the X-ray emission and its properties.

    This new image of GK Persei contains X-rays from Chandra (blue), optical data from NASA’s Hubble Space Telescope (yellow), and radio data from the National Science Foundation’s [NRAO] Very Large Array [VLA](pink). The X-ray data show hot gas and the radio data show emission from electrons that have been accelerated to high energies by the nova shock wave. The optical data reveal clumps of material that were ejected in the explosion. The nature of the point-like source on the lower left is unknown.

    NASA Hubble Telescope
    NASA/ESA Hubble

    NRAO VLA
    NRAO/VLA

    Over the years that the Chandra data span, the nova debris expanded at a speed of about 700,000 miles per hour. This translates to the blast wave moving about 90 billion miles during that period.

    One intriguing discovery illustrates how the study of nova remnants can provide important clues about the environment of the explosion. The X-ray luminosity of the GK Persei remnant decreased by about 40% over the 13 years between the Chandra observations, whereas the temperature of the gas in the remnant has essentially remained constant, at about one million degrees Celsius. As the shock wave expanded and heated an increasing amount of matter, the temperature behind the wave of energy should have decreased. The observed fading and constant temperature suggests that the wave of energy has swept up a negligible amount of gas in the environment around the star over the past 13 years. This suggests that the wave must currently be expanding into a region of much lower density than before, giving clues to stellar neighborhood in which GK Persei resides.

    A paper describing these results appeared in the March 10th issue of The Astrophysical Journal. The authors were Dai Takei (RIKEN, SPring-8 Center Japan), Jeremy Drake (Smithsonian Astrophysical Observatory), Hiroya Yamaguichi (Goddard Space Flight Center), Patrick Slane (Smithsonian Astrophysical Observatory), Yasunobu Uchimaya (Rikkyo University, Japan), Satoru Katsuda (Japan Aerospace Exploration Agency).

    See the full article here.

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

     
  • richardmitnick 4:53 am on March 16, 2015 Permalink | Reply
    Tags: , , NASA Chandra   

    From Chandra: “PSR B1509-58: A Young Pulsar Shows its Hand” 2009 

    April 3, 2009

    NASA Chandra

    1
    Credit NASA/CXC/SAO/P.Slane, et al.
    Release Date April 3, 2009

    A small, dense object only twelve miles in diameter is responsible for this beautiful X-ray nebula that spans 150 light years. At the center of this image made by NASA’s Chandra X-ray Observatory is a very young and powerful pulsar, known as PSR B1509-58, or B1509 for short. The pulsar is a rapidly spinning neutron star which is spewing energy out into the space around it to create complex and intriguing structures, including one that resembles a large cosmic hand. In this image, the lowest energy X-rays that Chandra detects are colored red, the medium range is green, and the most energetic ones are blue. Astronomers think that B1509 is about 1700 years old as measured in Earth’s time-frame (referring to when events are observable at Earth) and is located about 17,000 light years away.

    Neutron stars are created when massive stars run out of fuel and collapse. B1509 is spinning completely around almost 7 times every second and is releasing energy into its environment at a prodigious rate – presumably because it has an intense magnetic field at its surface, estimated to be 15 trillion times stronger than the Earth’s magnetic field.

    The combination of rapid rotation and ultra-strong magnetic field makes B1509 one of the most powerful electromagnetic generators in the Galaxy. This generator drives an energetic wind of electrons and ions away from the neutron star. As the electrons move through the magnetized nebula, they radiate away their energy and create the elaborate nebula seen by Chandra.

    In the innermost regions, a faint circle surrounds the pulsar, and marks the spot where the wind is rapidly decelerated by the slowly expanding nebula. In this way, B1509 shares some striking similarities to the famous Crab Nebula. However B1509’s nebula is 15 times wider than the Crab’s diameter of 10 light years.

    Finger-like structures extend to the north, apparently energizing knots of material in a neighboring gas cloud known as RCW 89. The transfer of energy from the wind to these knots makes them glow brightly in X-rays (orange and red features to the upper right). The temperature in this region appears to vary in a circular pattern around this ring of emission, suggesting that the pulsar may be precessing like a spinning top and sweeping an energizing beam around the gas in RCW 89.

    See the full article here.

    Another view

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    Pareidolia is the psychological phenomenon where people see recognizable shapes in clouds, rock formations, or otherwise unrelated objects or data. There are many examples of this phenomenon on Earth and in space.

    When an image from NASA’s Chandra X-ray Observatory of PSR B1509-58 — a spinning neutron star surrounded by a cloud of energetic particles –was released in 2009, it quickly gained attention because many saw a hand-like structure in the X-ray emission. In a new image of the system, X-rays from Chandra in gold are seen along with infrared data from NASA’s Wide-field Infrared Survey Explorer (WISE) telescope in red, green and blue. Pareidolia may strike again as some people report seeing a shape of a face in WISE’s infrared data. What do you see?

    NASA Wise Telescope
    WISE

    NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, also took a picture of the neutron star nebula in 2014, using higher-energy X-rays than Chandra.

    NASA NuSTAR

    PSR B1509-58 is about 17,000 light-years from Earth.
    JPL, a division of the California Institute of Technology in Pasadena, manages the WISE mission for NASA.

    Please help promote STEM in your local schools.

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

     
  • richardmitnick 6:05 pm on March 4, 2015 Permalink | Reply
    Tags: , , NASA Chandra   

    From Chandra: “Abell 2597: NASA’s Chandra Observatory Finds Cosmic Showers Halt Galaxy Growth” 

    NASA Chandra

    March 4, 2015

    Media contacts:
    Felicia Chou
    Headquarters, Washington
    202-358-0257
    felicia.chou@nasa.gov

    Janet Anderson
    Marshall Space Flight Center
    256-544-6162
    janet.l.anderson@nasa.gov

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

    New research shows how an unusual form of cosmic precipitation can affect the growth and evolution of galaxies. Over 200 galaxy clusters were surveyed in this new study using X-ray data from Chandra. These results provide evidence that this precipitation can slow down star formation in galaxies with giant black holes.

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    Credit X-ray: NASA/CXC/Michigan State Univ/G.Voit et al; Optical: NASA/STScI & DSS; H-alpha: Carnegie Obs./Magellan/W.Baade Telescope
    Release Date March 4, 2015

    This galaxy cluster comes from a sample of over 200 that were studied to determine how giant black holes at their centers affect the growth and evolution of their host galaxy, as reported in our latest press release. This study revealed that an unusual form of cosmic precipitation enables a feedback loop of cooling and heating, stifling star formation in the middle of these galaxy clusters.

    Abell 2597, shown here, is a galaxy cluster located about one billion light years from Earth. This image contains X-rays from NASA’s Chandra X-ray Observatory (blue), optical data from the Hubble Space Telescope and the Digitized Sky Survey (yellow) and emission from hydrogen atoms (red) from the Walter Baade Telescope in Chile.

    NASA Hubble Telescope
    Hubble

    Magellan 6.5 meter telescopes
    Magellan 6.5 meter Interior
    Walter Baade Telescope

    According to this new study, the regulation of the largest black hole and their host galaxies works as follows: in some galaxies, such as NGC 2597, hot gas is able to quickly cool through radiation and energy loss, in a process called precipitation. The clouds of cool gas that result then fall into the central supermassive black hole, producing jets that heat the gas and prevent further cooling.

    The researchers used Chandra data to estimate how long it should take for the gas to cool at different distances from the black holes in the study. Using that information, they were able to accurately predict the “weather” around each of the black holes.

    They found that the precipitation feedback loop driven by energy produced by the black hole jets prevents the showers of cold clouds from getting too strong. The Chandra data indicate that the regulation of this precipitation has been going on for the last 7 billion years or more.

    While a rain of cool clouds appears to play a key role in regulating the growth of some galaxies, the researchers have found other galaxies where the cosmic precipitation had shut off. The intense heat in these central galaxies, possibly from colliding with another galaxy cluster, likely “dried up” the precipitation around the black hole.

    Evidence was also found, in a few galaxy clusters, that strong bursts of outflows from regions near the black hole may have temporarily shut down precipitation, but the heating is not strong enough to result in conduction. In these cases, further cooling of gas should occur and active precipitation should resume in a few hundred million years.

    A pre-print of the Nature study by Mark Voit (Michigan State University), Megan Donahue (Michigan State), Greg Bryan (Columbia University), and Michael McDonald (Massachusetts Institute of Technology) is available online; the study builds on work by Voit and Donahue that was published in the January 20th, 2015 issue of The Astrophysical Journal Letters and is available online.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

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

     
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