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  • richardmitnick 3:07 pm on January 10, 2019 Permalink | Reply
    Tags: , , , , Cygnus A: Ricocheting Black Hole Jet Discovered by Chandra, NASA Chandra   

    From NASA Chandra: “Cygnus A: Ricocheting Black Hole Jet Discovered by Chandra” 

    NASA Chandra Banner

    NASA/Chandra Telescope


    From NASA Chandra

    2019-01-08

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    Cygnus A. Credit: X-ray: NASA/CXC/Columbia Univ./A. Johnson et al.; Optical: NASA/STScI

    A ricocheting jet blasting from a giant black hole has been captured by NASA’s Chandra X-ray Observatory, as reported in our latest press release. In this composite image of Cygnus A, X-rays from Chandra (red, green, and blue that represent low, medium and high energy X-rays) are combined with an optical view from the Hubble Space Telescope of the galaxies and stars in the same field of view. Chandra’s data reveal the presence of powerful jets of particles and electromagnetic energy that have shot out from the black hole. The jet on the left has slammed into a wall of hot gas, then ricocheted to punch a hole in a cloud of energetic particles, before it collides with another part of the gas wall.

    A labeled version outlines the key features described above. The main figure shows the location of the supermassive black hole, the jets, the point that the jet on the left ricocheted off a wall of intergalactic gas (“hotspot E”), and the point where the jet then struck the intergalactic gas a second time (“hotspot D”). The inset contains a close-up view of the hotspots on the left and the hole punched by the rebounding jet, which surrounds hotspot E. The image in the inset combines X-rays from all three energy ranges to give the greatest sensitivity to show fine structures such as the hole.

    The hole is visible because the path of the rebounding jet between hotspots E and D is almost directly along the line of sight to Earth, as shown by the schematic figure depicting the view of Cygnus A from above. A similar rebounding of the jet likely occurred between hotspots A and B but the hole is not visible because the path is not along the Earth’s line of sight.

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    Credit: NASA/CXC/M.Weiss

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    Credit: NASA/CXC/M.Weiss

    Cygnus A is a large galaxy that sits in the middle of a cluster of galaxies about 760 million light years from Earth. A supermassive black hole at the center of Cygnus A is rapidly growing as it pulls material swirling around it into its gravitational grasp. During this process, some of this material is redirected away from the black hole in the form of narrow beams, or jets. Such jets can significantly affect how the galaxy and its surroundings evolve.

    In a deep observation that lasted 23 days, scientists used Chandra to create a highly detailed map of both the jets and the intergalactic gas, which they used to track the path of the jets from the black hole. The jet on the left expanded after ricocheting and created a hole in the surrounding cloud of particles that is between 50,000 and 100,000 light years deep and only 26,000 light years wide. For context, the Earth is located about 26,000 light years away from the center of the Milky Way galaxy.

    The scientists are working to determine what forms of energy — kinetic energy, heat or radiation — the jet carries. The composition of the jet and the types of energy determine how the jet behaves when it ricochets, such as the size of the hole it creates. Theoretical models of the jet and its interactions with surrounding gas are needed to make conclusions about the jet’s properties.

    Energy produced by jets from black holes can heat intergalactic gas in galaxy clusters and prevent it from cooling and forming large numbers of stars in a central galaxy like Cygnus A. Thus, studying Cygnus A can tell scientists more about how jets from black holes interact with their surroundings.

    These results were presented at the 233rd meeting of the American Astronomical Society meeting in Seattle, WA, in a study led by Amalya Johnson of Columbia University in New York.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    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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  • richardmitnick 3:40 pm on December 14, 2018 Permalink | Reply
    Tags: Abell 2597, , , , Cosmic Fountain Powered by Giant Black Hole, , NASA Chandra   

    From NASA Chandra: “Cosmic Fountain Powered by Giant Black Hole” 

    NASA Chandra Banner

    NASA/Chandra Telescope


    From NASA Chandra

    2018-12-10

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    Abell 2597
    Credit: X-ray: NASA/CXC/SAO/G. Tremblay et al; Radio:ALMA: ESO/NAOJ/NRAO/G.Tremblay et al, NRAO/AUI/NSF/B.Saxton; Optical: ESO/VLT

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

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo

    Before electrical power became available, water fountains worked by relying on gravity to channel water from a higher elevation to a lower one. This water could then be redirected to shoot out of the fountain and create a centerpiece for people to admire.

    In space, awesome gaseous fountains have been discovered in the centers of galaxy clusters. One such fountain is in the cluster Abell 2597. There, vast amounts of gas fall toward a supermassive black hole, where a combination of gravitational and electromagnetic forces sprays most of the gas away from the black hole in an ongoing cycle lasting tens of millions of years.

    Scientists used data from the Atacama Large Millimeter/submillimeter Array (ALMA), the Multi-Unit Spectroscopic Explorer (MUSE) on ESO’s Very Large Telescope (VLT) and NASA’s Chandra X-ray Observatory to find the first clear evidence for the simultaneous inward and outward flow of gas being driven by a supermassive black hole.

    ESO MUSE on the VLT on Yepun (UT4),

    Cold gas falls toward the central black hole, like water entering the pump of a fountain. Some of this infalling gas (seen in the image as ALMA data in yellow) eventually reaches the vicinity of the black hole, where the black hole’s gravity causes the gas to swirl around with ever-increasing speeds, and the gas is heated to temperatures of millions of degrees. This swirling motion also creates strong electromagnetic forces that launch high-velocity jets of particles that shoot out of the galaxy.

    These jets push away huge amounts of hot gas detected by Chandra (purple) surrounding the black hole, creating enormous cavities that expand away from the center of the cluster. The expanding cavities also lift up clumps of warm and cold gas and carry them away from the black hole, as observed in the MUSE/VLT data (red).

    Eventually this gas slows down and the gravitational pull of material in the center of the galaxy causes the gas to rain back in on the black hole, repeating the entire process.

    A substantial fraction of the three billion solar masses of gas are pumped out by this fountain and form a filamentary nebula — or cosmic “spray” — that spans the innermost 100,000 light-years of the galaxy.

    These observations agree with predictions of models describing how matter falling towards black holes can generate powerful jets. Galaxy clusters like Abell 2597, containing thousands of galaxies, hot gas, and dark matter, are some of the largest structures in the entire Universe. Abell 2597 is located about 1.1 billion light years from Earth.

    A paper by Grant Tremblay (Harvard-Smithsonian Center for Astrophysics) et al. describing these results appeared in the September 18, 2018 issue of The Astrophysical Journal.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    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.

     
  • richardmitnick 2:38 pm on December 4, 2018 Permalink | Reply
    Tags: ASASSN-16oh, Astronomers have detected a bright X-ray outburst from a star in the Small Magellanic Cloud, , , , , Double Trouble: A White Dwarf Surprises Astronomers, NASA Chandra, Supersoft X-ray   

    From NASA Chandra: “Double Trouble: A White Dwarf Surprises Astronomers” 

    NASA Chandra Banner

    NASA/Chandra Telescope


    From NASA Chandra

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    Illustration of White Dwarf Accretion
    Credit: NASA/CXC/Texas Tech/T. Maccarone Illustration: NASA/CXC/M. Weiss

    Astronomers have detected a bright X-ray outburst from a star in the Small Magellanic Cloud, a nearby galaxy almost 200,000 light years from Earth. A combination of X-ray and optical data indicate that the source of this radiation is a white dwarf star that may be the fastest-growing white dwarf ever observed.

    In several billion years, our Sun will run out of most of its nuclear fuel and shrink down to a much smaller, fainter “white dwarf” star about the size of Earth. Because a mass equivalent to that of the Sun is packed into such a small volume, the gravity on the surface of a white dwarf is several hundred thousand times that of Earth.

    Unlike our Sun, most stars including white dwarfs, do not exist in isolation, but instead are part of pairs called “binary systems.” If the stars are close enough, the gravity of the white dwarf can pull matter away from its companion.

    A new study based on observations with NASA’s Chandra X-ray Observatory and Neil Gehrels Swift Observatory has reported the discovery of distinctive X-ray emission from a binary system containing a white dwarf called ASASSN-16oh.

    ASAS-SN’s hardware. Off the shelf Mark Elphick-Los Cumbres Observatory

    NASA Neil Gehrels Swift Observatory

    The discovery involves the detection of low-energy — what astronomers refer to as “soft” — X-rays, produced by gas at temperatures of several hundred thousand degrees. In contrast, higher-energy X-rays reveal phenomena at temperatures of tens of millions of degrees. The X-ray emission from ASASSN-16oh is much brighter than the soft X-rays produced by the atmospheres of normal stars, placing it in the special category of a supersoft X-ray source.

    For years, astronomers have thought that supersoft X-ray emission from white dwarf stars is produced by nuclear fusion in a hot, dense layer of hydrogen and helium nuclei. This volatile material accumulated from the infall of matter from the companion star onto the surface of the white dwarf, and led to a nuclear fusion explosion much like a hydrogen bomb.

    However, ASASSN-16oh shows there is more to the story. This binary was first discovered by the All-Sky Automated Survey for Supernovae (ASASSN), a collection of about 20 optical telescopes distributed around the globe to automatically survey the entire sky every night for supernovas and other transient events. Astronomers then used Chandra and Swift to detect the supersoft X-ray emission.

    “In the past, the supersoft sources have all been associated with nuclear fusion on the surface of white dwarfs,” said lead author Tom Maccarone, a professor in the Texas Tech Department of Physics & Astronomy who led the new paper that appears in the December 3rd issue of Nature Astronomy.

    If nuclear fusion is the cause of the supersoft X-rays from ASASSN-16oh then it should begin with an explosion and the emission should come from the entire surface of the white dwarf. However, the optical light does not increase quickly enough to be caused by an explosion and the Chandra data show that the emission is coming from a region smaller than the surface of the white dwarf. The source is also a hundred times fainter in optical light than white dwarfs known to be undergoing fusion on their surface. These observations, plus the lack of evidence for gas flowing away from the white dwarf, provide strong arguments against fusion having taken place on the white dwarf.

    Because none of the signs of nuclear fusion are present, the authors present a different scenario. As with the fusion explanation the white dwarf is pulling gas away from a companion star, a red giant. In a process called accretion, the gas is pulled onto a large disk surrounding the white dwarf and becomes hotter as it spirals toward the white dwarf, as shown in our illustration. The gas then falls onto the white dwarf, producing X-rays along a belt where the disk meets the star. The rate of inflow of matter through the disk varies by a large amount. When the material starts flowing more quickly, the X-ray brightness of the system becomes much higher.

    “The transfer of mass is happening at a higher rate than in any system we’ve caught in the past,” added Maccarone.

    If the white dwarf keeps gaining mass it may reach a mass limit and destroy itself in a Type Ia supernova explosion, a type of event used to discover that the expansion of the universe is accelerating. The team’s analysis suggests that the white dwarf is already unusually massive so ASASSN-16oh may be relatively close — in astronomical terms — to exploding as a supernova.

    “Our result contradicts a decades-long consensus about how supersoft X-ray emission from white dwarfs is produced,” said co-author Thomas Nelson from the University of Pittsburgh. “We now know that the X-ray emission can be made in two different ways: by nuclear fusion or by the accretion of matter from a companion.”

    Also involved in the study were scientists from Texas A&M University, NASA Goddard Space Flight Center, University of Southampton, University of the Free State in the Republic of South Africa, the South African Astronomical Observatory, Michigan State University, State University of New Jersey, Warsaw University Observatory, Ohio State University and the University of Warwick.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    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.

     
  • richardmitnick 9:20 am on November 16, 2018 Permalink | Reply
    Tags: Abell 1033: To Boldly Go into Colliding Galaxy Clusters, , , , , NASA Chandra   

    From NASA Chandra: “Abell 1033: To Boldly Go into Colliding Galaxy Clusters” 

    NASA Chandra Banner

    NASA/Chandra Telescope


    From NASA Chandra

    November 15, 2018


    Composite

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    X-ray

    32
    Optical

    4
    Radio
    Credit X-ray: NASA/CXC/Leiden Univ./F. de Gasperin et al; Optical: SDSS; Radio: LOFAR/ASTRON, NCRA/TIFR/GMRT

    A new composite image of the galaxy cluster Abell 1033 bears a striking resemblance to the Starship Enterprise from Star Trek.

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    USS Enterprise NCC 1701 Credit: Smithsonian National Air & Space Museum

    X-rays from Chandra (purple), radio emission from LOFAR (blue), and SDSS optical data were combined in this image.

    Abell 1033 is a merger of two galaxy clusters, the largest structures in the Universe held together by gravity.

    Pareidolia is the phenomenon where people see familiar shapes and patterns in otherwise random data.

    Hidden in a distant galaxy cluster collision are wisps of gas resembling the starship Enterprise — an iconic spaceship from the “Star Trek” franchise.

    Galaxy clusters — cosmic structures containing hundreds or even thousands of galaxies — are the largest objects in the Universe held together by gravity. Multi-million-degree gas fills the space in between the individual galaxies. The mass of the hot gas is about six times greater than that of all the galaxies combined. This superheated gas is invisible to optical telescopes, but shines brightly in X-rays, so an X-ray telescope like NASA’s Chandra X-ray Observatory is required to study it.

    By combining X-rays with other types of light, such as radio waves, a more complete picture of these important cosmic objects can be obtained. A new composite image of the galaxy cluster Abell 1033, including X-rays from Chandra (purple) and radio emission from the Low-Frequency Array (LOFAR) network in the Netherlands (blue), does just that. Optical emission from the Sloan Digital Sky Survey is also shown. The galaxy cluster is located about 1.6 billion light years from Earth.

    ASTRON LOFAR Radio Antenna Bank, Netherlands

    SDSS Telescope at Apache Point Observatory, near Sunspot NM, USA, Altitude 2,788 meters (9,147 ft)

    Using X-ray and radio data, scientists have determined that Abell 1033 is actually two galaxy clusters in the process of colliding. This extraordinarily energetic event, happening from the top to the bottom in the image, has produced turbulence and shock waves, similar to sonic booms produced by a plane moving faster than the speed of sound.

    In Abell 1033, the collision has interacted with another energetic cosmic process — the production of jets of high-speed particles by matter spiraling into a supermassive black hole, in this case one located in a galaxy in one of the clusters. These jets are revealed by radio emission to the left and right sides of the image. The radio emission is produced by electrons spiraling around magnetic field lines, a process called synchrotron emission.

    The electrons in the jets are traveling at very close to the speed of light. As the galaxy and its black hole moved toward the lower part of the image, the jet on the right slowed down as it crashed into hot gas in the other galaxy cluster. The jet on the left did not slow down because it encountered much less hot gas, giving a warped appearance for the jets, rather than the straight line that is typically seen.

    This image of Abell 1033 also provides an example of “pareidolia”, a psychological phenomenon where familiar shapes and patterns are seen in otherwise random data. In Abell 1033, the structures in the data create an uncanny resemblance to many of the depictions of the fictional Starship Enterprise from Star Trek.

    In terms of astrophysical research, a detailed study of the image shows that the energy of the electrons in the “saucer section” and neck of the starship-shaped radio emission in Abell 1033 is higher than that found in the stardrive section towards the lower left (see labels). This suggests that the electrons have been reenergized, presumably when the jets interact with turbulence or shock waves in the hot gas. The energetic electrons producing the radio emission will normally lose substantial amounts of energy over tens to hundreds of millions of years as they radiate. The radio emission would then become undetectable. However, the vastly extended radio emission observed in Abell 1033, extending over about 500,000 light years, implies that energetic electrons are present in larger quantities and with higher energies than previously thought. One idea is that the electrons have been given a further boost in energy by extra bouts of shocks and turbulence.

    Other sources of radio emission in the image besides the starship-shaped object are the shorter jets from another galaxy (labeled “short jets”) and a “radio phoenix” consisting of a cloud of electrons that faded in radio emission but was then reenergized when shock waves compressed the cloud. This caused the cloud to once again shine at radio frequencies, as we reported back in 2015.

    The team who made this study will use observations with Chandra and LOFAR to look for further examples of colliding galaxy clusters with warped radio emission, to further their understanding of these energetic objects.

    A paper describing this result was published in the October 4th, 2017 issue of Science Advances. The authors of the paper are Francesco de Gasperin, Huib Intema, Timothy Shimwell (Leiden University, the Netherlands), Gianfranco Brunetti (Institute of Radio Astronomy, Italy), Marcus Bruggen (University of Hamburg, Germany), Torsten Enblin (Max Planck Institute for Astrophysics, Germany), Reinout van Weeren (Leiden), Annalisa Bonafede (Hamburg), and Huub Rottgering (Leiden).

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    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.

     
  • richardmitnick 12:20 pm on November 7, 2018 Permalink | Reply
    Tags: , , , , , Demonstrated that there is an upper limit – now called the Chandrasekhar limit – to the mass of a white dwarf star, NASA Chandra,   

    From COSMOS Magazine: “Science history: The astrophysicist who defined how stars behave” Subrahmanyan Chandrasekhar 

    Cosmos Magazine bloc

    From COSMOS Magazine

    07 November 2018
    Jeff Glorfeld

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    Subrahmanyan Chandrasekhar meets the press in 1983, shortly after winning the Nobel Prize. Bettmann / Contributor / Getty Images

    Subrahmanyan Chandrasekhar was so influential, NASA honoured him by naming an orbiting observatory after him.

    NASA/Chandra X-ray Telescope

    The NASA webpage devoted to astrophysicist Subrahmanyan Chandrasekhar says he “was known to the world as Chandra. The word chandra means ‘moon’ or ‘luminous’ in Sanskrit.”

    Subrahmanyan Chandrasekhar was born on October 19, 1910, in Lahore, Pakistan, which at the time was part of British India. NASA says that he was “one of the foremost astrophysicists of the 20th century. He was one of the first scientists to couple the study of physics with the study of astronomy.”

    The Encyclopaedia Britannica adds that, with William A. Fowler, he won the 1983 Nobel Prize for physics, “for key discoveries that led to the currently accepted theory on the later evolutionary stages of massive stars”.

    According to an entry on the website of the Harvard-Smithsonian Centre for Astrophysics, early in his career, between 1931 and 1935, he demonstrated that there is an upper limit – now called the Chandrasekhar limit – to the mass of a white dwarf star.

    “This discovery is basic to much of modern astrophysics, since it shows that stars much more massive than the Sun must either explode or form black holes,” the article explains.

    When he first proposed his theory, however, it was opposed by many, including Albert Einstein, “who refused to believe that Chandrasekhar’s findings could result in a star collapsing down to a point”.

    Writing for the Nobel Prize committee, Chandra described how he approached a project.

    “My scientific work has followed a certain pattern, motivated, principally, by a quest after perspectives,” he wrote.

    “In practice, this quest has consisted in my choosing (after some trials and tribulations) a certain area which appears amenable to cultivation and compatible with my taste, abilities, and temperament. And when, after some years of study, I feel that I have accumulated a sufficient body of knowledge and achieved a view of my own, I have the urge to present my point of view, ab initio, in a coherent account with order, form, and structure.

    “There have been seven such periods in my life: stellar structure, including the theory of white dwarfs (1929-1939); stellar dynamics, including the theory of Brownian motion (1938-1943); the theory of radiative transfer, including the theory of stellar atmospheres and the quantum theory of the negative ion of hydrogen and the theory of planetary atmospheres, including the theory of the illumination and the polarisation of the sunlit sky (1943-1950); hydrodynamic and hydromagnetic stability, including the theory of the Rayleigh-Benard convection (1952-1961); the equilibrium and the stability of ellipsoidal figures of equilibrium, partly in collaboration with Norman R. Lebovitz (1961-1968); the general theory of relativity and relativistic astrophysics (1962-1971); and the mathematical theory of black holes (1974- 1983).”

    In 1999, four years after his death on August 21, 1995, NASA launched an x-ray observatory named Chandra, in his honour. The observatory studies the universe in the x-ray portion of the electromagnetic spectrum.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

     
  • richardmitnick 10:37 am on November 6, 2018 Permalink | Reply
    Tags: , , , , , , From ESO and ALMA: "ALMA and MUSE Detect Galactic Fountain-Galaxy-Scale Fountain Seen in Full Glory", , NASA Chandra,   

    From ESO and ALMA: “ALMA and MUSE Detect Galactic Fountain-Galaxy-Scale Fountain Seen in Full Glory” 

    ESO 50 Large

    From European Southern Observatory

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

    From ALMA

    6 November 2018
    ESO Contacts

    Grant Tremblay
    Harvard-Smithsonian Center for Astrophysics
    Cambridge, USA
    Tel: +1 207 504 4862
    Email: grant.tremblay@cfa.harvard.edu

    Francoise Combes
    LERMA, Paris Observatory
    Paris, France
    Email: francoise.combes@obspm.fr

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

    ALMA Contacts
    Nicolás Lira
    Education and Public Outreach Coordinator
    Joint ALMA Observatory, Santiago – Chile
    Phone: +56 2 2467 6519
    Cell phone: +56 9 9445 7726
    Email: nicolas.lira@alma.cl

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory Charlottesville, Virginia – USA
    Phone: +1 434 296 0314
    Cell phone: +1 202 236 6324
    Email: cblue@nrao.edu

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

    Calum Turner
    ESO Assistant Public Information Officer
    Garching bei München, Germany
    Phone: +49 89 3200 6670
    Email: calum.turner@eso.org

    1
    Composite image of the Abell 2597 galaxy cluster showing the fountain-like flow of gas powered by the supermassive black hole in the central galaxy. The yellow is ALMA data of the cold gas. The red is data from MUSE on the Very Large Telescope Yepun UT4 showing the hot hydrogen gas in the same region. The extend purple is the extended hot, ionized gas as imaged by the Chandra X-ray Observatory. Credit: ALMA (ESO/NAOJ/NRAO), Tremblay et al.; NRAO/AUI/NSF, B. Saxton; NASA/Chandra; ESO/VLT

    NASA/Chandra X-ray Telescope

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    ALMA image of cold molecular gas in Abell 2597. Credit: ALMA (ESO/NAOJ/NRAO), G. Tremblay et al.

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    Animation of the MUSE H-alpha data showing the different velocities of material in the “galactic fountain.” Credit: ESO; G. Tremblay et al.

    ESO MUSE on the VLT on Yepun (UT4),

    ESO MUSE on VLT Yepun UT4

    A mere one billion light-years away in the nearby galaxy cluster known as Abell 2597, there lies a gargantuan galactic fountain. A massive black hole at the heart of a distant galaxy has been observed pumping a vast spout of cold molecular gas into space, which then rains back onto the black hole as an intergalactic deluge .The in- and outflow of such a vast cosmic fountain has never before been observed in combination, and has its origin in the innermost 100 000 light-years of the brightest galaxy in the Abell 2597 cluster.

    “This is possibly the first system in which we find clear evidence for both cold molecular gas inflow toward the black hole and outflow or uplift from the jets that the black hole launches,” explained Grant Tremblay of the Harvard-Smithsonian Center for Astrophysics and former ESO Fellow, who led this study. “The supermassive black hole at the centre of this giant galaxy acts like a mechanical pump in a fountain.”

    Tremblay and his team used ALMA to track the position and motion of molecules of carbon monoxide within the nebula. These cold molecules, with temperatures as low as minus 250–260°C, were found to be falling inwards to the black hole. The team also used data from the MUSE instrument on ESO’s Very Large Telescope to track warmer gas — which is being launched out of the black hole in the form of jets.

    “The unique aspect here is a very detailed coupled analysis of the source using data from ALMA and MUSE,” Tremblay explained. “The two facilities make for an incredibly powerful combination.”

    Together these two sets of data form a complete picture of the process; cold gas falls towards the black hole, igniting the black hole and causing it to launch fast-moving jets of incandescent plasma into the void. These jets then spout from the black hole in a spectacular galactic fountain. With no hope of escaping the galaxy’s gravitational clutches, the plasma cools off, slows down, and eventually rains back down on the black hole, where the cycle begins anew.

    In an earlier study by the same authors published in the journal Nature, the researchers were able to verify the interconnection between the black hole and the galactic fountain by observing the region across a range of wavelengths, or portions of the spectrum. By studying the location and motion of molecules of carbon monoxide (CO) with ALMA, which shine brightly in millimeter-wavelength light, the researchers could measure the motion of the gas as it falls in toward the black hole.

    The ALMA and MUSE data were combined with a new, ultra-deep observation of the cluster by NASA’s Chandra X-ray Observatory, revealing the hot phase of this fountain in exquisite detail, noted the researchers.

    This unprecedented observation could shed light on the life cycle of galaxies. The team speculates that this process may be not only common, but also essential to understanding galaxy formation. While the inflow and outflow of cold molecular gas have both previously been detected, this is the first time both have been detected within one system, and hence the first evidence that the two make up part of the same vast process.

    Abell 2597 is found in the constellation Aquarius, and is named for its inclusion in the Abell catalogue of rich clusters of galaxies. The catalogue also includes such clusters as the Fornax cluster, the Hercules cluster, and Pandora’s cluster.

    More information

    This research was presented in a paper entitled “A Galaxy-Scale Fountain of Cold Molecular Gas Pumped by a Black Hole”, which appeared in The Astrophysical Journal.

    The team was composed of G. R. Tremblay (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA; Yale Center for Astronomy and Astrophysics, Yale University, New Haven, USA), F. Combes (LERMA, Observatoire de Paris, Sorbonne University, Paris, France), J. B. R. Oonk (ASTRON, Dwingeloo, the Netherlands; Leiden Observatory, the Netherlands), H. R. Russell (Institute of Astronomy, Cambridge University, UK), M. A. McDonald (Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, USA), M. Gaspari (Department of Astrophysical Sciences, Princeton University, USA), B. Husemann (Max-Planck-Institut für Astronomie, Heidelberg, Germany), P. E. J. Nulsen (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA; ICRAR, University of Western Australia, Crawley, Australia), B. R. McNamara (Physics & Astronomy Department, Waterloo University, Canada), S. L. Hamer (CRAL, Observatoire de Lyon, Université Lyon, France), C. P. O’Dea (Department of Physics & Astronomy, University of Manitoba, Winnipeg, Canada; School of Physics & Astronomy, Rochester Institute of Technology, USA), S. A. Baum (School of Physics & Astronomy, Rochester Institute of Technology, USA; Faculty of Science, University of Manitoba, Winnipeg, Canada), T. A. Davis (School of Physics & Astronomy, Cardiff University, UK), M. Donahue (Physics and Astronomy Department, Michigan State University, East Lansing, USA), G. M. Voit (Physics and Astronomy Department, Michigan State University, East Lansing, USA), A. C. Edge (Department of Physics, Durham University, UK), E. L. Blanton (Astronomy Department and Institute for Astrophysical Research, Boston University, USA), M. N. Bremer (H. W. Wills Physics Laboratory, University of Bristol, UK), E. Bulbul (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), T. E. Clarke (Naval Research Laboratory Remote Sensing Division, Washington, DC, USA), L. P. David (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), L. O. V. Edwards (Physics Department, California Polytechnic State University, San Luis Obispo, USA), D. Eggerman (Yale Center for Astronomy and Astrophysics, Yale University, New Haven, USA), A. C. Fabian (Institute of Astronomy, Cambridge University, UK), W. Forman (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), C. Jones (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), N. Kerman (Yale Center for Astronomy and Astrophysics, Yale University, New Haven, USA), R. P. Kraft (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), Y. Li (Center for Computational Astrophysics, Flatiron Institute, New York, USA; Department of Astronomy, University of Michigan, Ann Arbor, USA), M. Powell (Yale Center for Astronomy and Astrophysics, Yale University, New Haven, USA), S. W. Randall (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), P. Salomé (LERMA, Observatoire de Paris, Sorbonne University, Paris, France), A. Simionescu (Institute of Space and Astronautical Science [ISAS], Kanagawa, Japan), Y. Su (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), M. Sun (Department of Physics and Astronomy, University of Alabama in Huntsville, USA), C. M. Urry (Yale Center for Astronomy and Astrophysics, Yale University, New Haven, USA), A. N. Vantyghem (Physics & Astronomy Department, Waterloo University, Canada), B. J. Wilkes (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA) and J. A. ZuHone (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA).

    See the full ESO article here .
    See the full ALMA article here .


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

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    ESO 3.6m telescope & HARPS at Cerro LaSilla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

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    Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT.

    ESO/NTT at Cerro La Silla, Chile, at an altitude of 2400 metres


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

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).

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

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

    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 5:58 pm on October 25, 2018 Permalink | Reply
    Tags: NASA Chandra, ,   

    From NASA Spaceflight: “Two NASA space telescopes returning to work following sick days” 

    NASA Spaceflight

    From NASA Spaceflight

    October 23, 2018
    Chris Bergin

    1
    NASA/ESA Hubble

    Two flagship space telescopes are returning to their respective operations after they both entered safe mode around the same time earlier this month. The Hubble Space Telescope is close to moving back into normal science observations following a gyro issue, while the Chandra Space Telescope has now resumed its detections of X-ray emissions from very hot regions of the universe.
    Hubble was the first to report a problem back on October 5, relating to a backup gyroscope that was incorrectly returning extremely high rotation rates. Hubble’s gyros measure the speed at which the spacecraft is turning, and is needed to help Hubble turn and lock on to new targets.

    The Hubble Space Telescope is one of the most famous spacecraft ever launched by NASA and is closing it on its 30th anniversary since launch.

    Shuttle Discovery – STS-31 in 1990 – was Hubble’s ride into space, with her crew including former NASA Administrator Charlie Bolden, reaching a 380 statute mile orbit – higher than most orbiters would normally head to in space.

    Giving birth to Hubble on orbit didn’t go as smoothly as was hoped, as one of the observatory’s solar arrays stopped as it was unfurling. The plan for such a scenario was to conduct a contingency spacewalk. However, the ground teams eventually persuaded the array to deploy.

    2
    Hubble deployment during Discovery’s mission via L2 Historical.

    While Discovery completed her mission – and landed at Edwards Air Force Base in California on April 29 in 1990 – scientists were eagerly waiting to get their hands on the first images from the latest NASA hardware in space.

    Those first images showed Hubble had a problem.

    Ultimately, Discovery’s mission was a success, but the images revealed Hubble’s main mirror had been ground incorrectly, effectively compromising Hubble’s eyesight. A major effort was undertaken to fix the problem, via another Shuttle mission.

    It was Discovery’s younger sister that came to the rescue of Hubble in 1993, as Endeavour launched on only her fifth mission to carry out a critical service mission, with the main goal of correcting the telescope’s impaired vision.

    STS-61’s five grueling EVAs in a row successfully installed a corrective optics package – along with new solar arrays – during the highly complex 11-day mission.

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    Endeavour to the rescue during repair mission to Hubble – via L2 Historical.

    Hubble was back to full health and started to provide the stunning images of the cosmos that have fascinated the entire human race ever since.

    Discovery would return to Hubble in 1997, as STS-82’s mission upgraded the telescope’s scientific instruments and increased its research capabilities. Discovery would visit her favorite telescope once again on the third servicing mission in 1999, replacing all six of Hubble’s gyroscopes – three of which had failed – along with replacing a Fine Guidance Sensor (FGS) and the telescope’s computer.

    In what was Columbia’s penultimate mission prior to her tragic loss, STS-109 carried out the fourth servicing mission in 2002, with each visit extending the life of the telescope.

    The five-EVA mission installed the Advanced Camera for Surveys (ACS), new rigid Solar Arrays (SA3), a new Power Control Unit (PCU) and a new Cryocooler for the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). Columbia also provided Hubble with a farewell push, as the orbiter reboosted the telescope to a higher orbit.

    NASA Hubble Advanced Camera forSurveys

    NASA/Hubble NICMOS

    However, due to Columbia’s loss the following year, NASA managers were left with a dilemma, one that was likely to result in the telescope deorbited.

    Hubble was next scheduled to be serviced in 2005, yet NASA’s own Return To Flight (RTF) rules insisted on the “safe haven” requirement, allowing for an orbiter, damaged during launch, to fly to the International Space Station (ISS) for its crew to wait for another shuttle to bring them home safe.

    Based on these rules, then-NASA Chief Sean O’Keefe resisted the calls for Hubble to be serviced, whilst noting an alternative mission using robotic assets would not be developed in time to save the telescope. Hubble’s gyroscopes were expected to fail – and its batteries to run out – no later than 2010.

    Mr. O’Keefe’s successor, Mike Griffin, noted the NASA stance was based mainly on the understandable pain associated with losing Columbia and the need to not take any unnecessary chances with the orbiters and their crews during the final era of their service.

    As it stood, NASA was expected to press ahead with a plan to deorbit Hubble into the Pacific Ocean.

    Thankfully, the Return To Flight of the Shuttle fleet showed the array of safety improvements allowed for the final Hubble Servicing Mission (SM-4) to be re-evaluated. However, the challenge of launching a mission without the Safe Haven of the ISS being available needed to be solved.

    That solution came in the form of another Shuttle, ready to launch within days of a problem on an elaborate rescue mission.

    Administrator Griffin eventually approved SM-4 for Atlantis and STS-125, after the Space Shuttle Program (SSP) started to prove its new safety measures were working – such as the increasing the mitigation of External Tank foam loss and advances in Thermal Protection System (TPS) inspection, along with repair techniques – during the opening salvo of post-RTF missions.

    The best possible crew were assigned to Atlantis for the final rendezvous between the world-famous vehicles, led by commander Scott Altman, assisted by six crewmembers that included John Grunsfeld and Mike Massimino.

    Endeavour would also receive a co-star role by standing by as the STS-400 rescue mission, seeing her sat on Pad 39B ready to launch at short notice in the event Atlantis’ launch – from Pad 39A – suffered a major issue during the ride uphill on what proved to be a delayed launch date, as Hubble itself worked through problems on orbit.

    That contingency wasn’t required, as Atlantis and her crew conducted a flawless launch and rendezvous with Hubble in May 2009 – no easy task even under nominal conditions, as the orbiters use up nearly half of their prop capability just to reach the “height” of the telescope’s orbit and can endure higher MMOD risks.

    The 14-day mission involved five back-to-back EVAs, including its own challenges – highlighted by Massimino literally using brute force to pull off the STIS handrail from the telescope during EVA-4.

    However, the mission achieved all of its primary goals, including the installation of two new instruments, namely the Cosmic Origins Spectrograph (COS) and the Wide Field Camera 3 (WFC 3), leaving Hubble in a great condition to continue its role for many years to come.

    NASA Hubble Cosmic Origins Spectrograph

    NASA/ESA Hubble WFC3

    NASA explained that a wheel inside the gyro spins at a constant rate of 19,200 revolutions per minute. This wheel is mounted in a sealed cylinder, called a float, which is suspended in a thick fluid. Electricity is carried to the motor by thin wires, approximately the size of a human hair, that are immersed in the fluid. Electronics within the gyro detect very small movements of the axis of the wheel and communicate this information to Hubble’s central computer.

    These gyros have two modes – high and low. High mode is a coarse mode used to measure large rotation rates when the spacecraft turns across the sky from one target to the next. Low mode is a precision mode used to measure finer rotations when the spacecraft locks onto a target and needs to stay very still.

    In an attempt to correct the erroneously high rates produced by the backup gyro, the Hubble operations team executed a running restart of the gyro on October 16. This procedure turned the gyro off for one second and then restarted it before the wheel spun down. The intention was to clear any faults that may have occurred during startup after the gyro had been off for more than 7.5 years. However, the resulting data showed no improvement in the gyro’s performance.

    “On October 18, the Hubble operations team commanded a series of spacecraft maneuvers, or turns, in opposite directions to attempt to clear any blockage that may have caused the float to be off-center and produce the exceedingly high rates. During each maneuver, the gyro was switched from high mode to low mode to dislodge any blockage that may have accumulated around the float,” NASA added.

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    Hubble’s gyros overview – via ESA

    Following the October 18 maneuvers, the team noticed a significant reduction in the high rates, allowing rates to be measured in low mode for brief periods of time. The following day, the operations team commanded Hubble to perform additional maneuvers and gyro mode switches, which appear to have cleared the issue. Data showed the gyro rates now look normal in both high and low mode.

    Hubble then executed additional maneuvers to make sure that the gyro remained stable within operational limits as the spacecraft moved. The team saw no problems and continued to observe the gyro through the weekend to ensure that it remained stable.

    “The Hubble operations team plans to execute a series of tests to evaluate the performance of the gyro under conditions similar to those encountered during routine science observations, including moving to targets, locking on to a target, and performing precision pointing. After these engineering tests have been completed, Hubble is expected to soon return to normal science operations,” NASA said.

    Meanwhile, the Chandra X-ray Observatory has returned to science operations.

    Chandra’s launch was the most eventful element of the spacecraft’s early days, with Shuttle Columbia having several tantrums before finally lofting the spacecraft into space.

    STS-93 suffered an abort just seconds prior to the initial launch attempt, before finally launching on 23 July 1999 from KSC’s 39B. Eileen Collins became the first female shuttle Commander on this flight.

    Problems were noted immediately after liftoff, when a gold pin – used to plug an oxidizer post in Columbia’s right engine – came loose and was violently ejected during ignition, striking the engine nozzle’s inner surface and tearing open three cooling tubes containing hydrogen – causing a leak. An electrical short in the center engine’s primary controller also kept controllers busy, before Columbia made it to orbit, albeit ending with a LOX Level Cutoff.

    The Chandra X-ray Observatory (CXO), previously known as the Advanced X-ray Astrophysics Facility (AXAF), is a Flagship-class space observatory.

    Chandra is 19 years old, which is well beyond the original design lifetime of 5 years. In 2001, NASA extended its lifetime to 10 years. It is now well into its extended mission and is expected to continue carrying out forefront science for many years to come.

    As with Hubble, a gyro was believed to be the issue relating to entering safe mode on October 10.

    Safe mode involves putting the observatory into a safe configuration, where critical hardware is swapped to backup units, the spacecraft points so that the solar panels get maximum sunlight, and the mirrors point away from the Sun.

    “Analysis of available data indicates the transition to safe mode was normal behavior for such an event. All systems functioned as expected and the scientific instruments are safe. The cause of the safe mode transition (possibly involving a gyroscope) is under investigation,” NASA noted at the time.

    6
    An overview of Chandra – via NASA

    Five days later, the cause of Chandra’s safe mode event was understood and the Operations team successfully returned the spacecraft to its normal pointing mode. The safe mode was caused by a glitch in one of Chandra’s gyroscopes resulting in a 3-second period of bad data that in turn led the onboard computer to calculate an incorrect value for the spacecraft momentum. The erroneous momentum indication then triggered the safe mode.

    “The team has completed plans to switch gyroscopes and place the gyroscope that experienced the glitch in reserve. Once configured with a series of pre-tested flight software patches, the team will return Chandra to science operations which are expected to commence by the end of this week,” NASA added.

    That remedy appears to have worked, as on Tuesday NASA noted that Chandra had returned to science operations, with more details to follow later in the week.

    See the full article here .

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    NASASpaceFlight.com, now in its eighth year of operations, is already the leading online news resource for everyone interested in space flight specific news, supplying our readership with the latest news, around the clock, with editors covering all the leading space faring nations.

    Breaking more exclusive space flight related news stories than any other site in its field, NASASpaceFlight.com is dedicated to expanding the public’s awareness and respect for the space flight industry, which in turn is reflected in the many thousands of space industry visitors to the site, ranging from NASA to Lockheed Martin, Boeing, United Space Alliance and commercial space flight arena.

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  • richardmitnick 8:44 pm on October 18, 2018 Permalink | Reply
    Tags: , , , , Dame Susan Jocelyn Bell Burnell first discovered pulsars in 1968, Kes 75: Milky Way's Youngest Pulsar Exposes Secrets of Star's Demise, NASA Chandra   

    From NASA Chandra: “Kes 75: Milky Way’s Youngest Pulsar Exposes Secrets of Star’s Demise” 

    NASA Chandra Banner

    NASA/Chandra Telescope


    From NASA Chandra

    1
    Composite

    2
    X-ray

    1
    Optical

    Since their first discovery in the 1960s, over 2,000 pulsars — rapidly spinning, dense stellar cores — have been found.

    Dame Susan Jocelyn Bell Burnell, discovered pulsars with radio astronomy. Jocelyn Bell at the Mullard Radio Astronomy Observatory, Cambridge University, taken for the Daily Herald newspaper in 1968. Denied the Nobel.

    Data from NASA’s Chandra X-ray Observatory has confirmed the youngest known pulsar in our Milky Way galaxy.

    This pulsar, known as Kes 75, is located about 19,000 light years from Earth.

    Scientists have uncovered interesting properties of Kes 75 that could help them better understand how some stars end their lives.

    Scientists have confirmed the identity of the youngest known pulsar in the Milky Way galaxy using data from NASA’s Chandra X-ray Observatory. This result could provide astronomers new information about how some stars end their lives.

    After some massive stars run out of nuclear fuel, then collapse and explode as supernovas, they leave behind dense stellar nuggets called “neutron stars”. Rapidly rotating and highly magnetized neutron stars produce a lighthouse-like beam of radiation that astronomers detect as pulses as the pulsar’s rotation sweeps the beam across the sky.

    Since Jocelyn Bell Burnell, Antony Hewish, and their colleagues first discovered pulsars through their radio emission in the 1960s, over 2,000 of these exotic objects have been identified.

    Dame Susan Jocelyn Bell Burnell 2009

    However, many mysteries about pulsars remain, including their diverse range of behaviors and the nature of stars that form them.

    New data from Chandra are helping address some of those questions. A team of astronomers has confirmed that the supernova remnant Kes 75, located about 19,000 light years from Earth, contains the youngest known pulsar in the Milky Way galaxy.

    The rapid rotation and strong magnetic field of the pulsar have generated a wind of energetic matter and antimatter particles that flow away from the pulsar at near the speed of light . This pulsar wind has created a large, magnetized bubble of high-energy particles called a pulsar wind nebula, seen as the blue region surrounding the pulsar.

    In this composite image of Kes 75, high-energy X-rays observed by Chandra are colored blue and highlight the pulsar wind nebula surrounding the pulsar, while lower-energy X-rays appear purple and show the debris from the explosion. A Sloan Digital Sky Survey optical image reveals stars in the field.

    The Chandra data taken in 2000, 2006, 2009, and 2016 show changes in the pulsar wind nebula with time. Between 2000 and 2016, the Chandra observations reveal that the outer edge of the pulsar wind nebula is expanding at a remarkable 1 million meters per second, or over 2 million miles per hour.

    This high speed may be due to the pulsar wind nebula expanding into a relatively low-density environment. Specifically, astronomers suggest it is expanding into a gaseous bubble blown by radioactive nickel formed in the explosion and ejected as the star exploded. This nickel also powered the supernova light, as it decayed into diffuse iron gas that filled the bubble. If so, this gives astronomers insight into the very heart of the exploding star and the elements it created.

    The expansion rate also tells astronomers that Kes 75 exploded about five centuries ago as seen from Earth. (The object is some 19,000 light years away, but astronomers refer to when its light would have arrived at Earth.) Unlike other supernova remnants from this era such as Tycho and Kepler, there is no known evidence from historical records that the explosion that created Kes 75 was observed.

    Why wasn’t Kes 75 seen from Earth? The Chandra observations along with previous ones from other telescopes indicate that the interstellar dust and gas that fill our Galaxy are very dense in the direction of the doomed star. This would have rendered it too dim to be seen from Earth several centuries ago.

    The brightness of the pulsar wind nebula has decreased by 10% from 2000 to 2016, mainly concentrated in the northern area, with a 30% decrease in a bright knot. The rapid changes observed in the Kes 75 pulsar wind nebula, as well as its unusual structure, point to the need for more sophisticated models of the evolution of pulsar wind nebulas.

    A paper describing these results appeared in The Astrophysical Journal and is available online. The authors are Stephen Reynolds, Kazimierz Borokowski, and Peter Gwynne from North Carolina 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 9:21 pm on October 16, 2018 Permalink | Reply
    Tags: "We have a case of cosmic look-alikes " said co-author Geoffrey Ryan of UMCP-so the simplest explanation is that they are from the same family of objects.", , , , , , , GW170817 and GRB 150101B, , NASA Chandra   

    From NASA Chandra: All in the Family: Kin of Gravitational-Wave Source Discovered 

    NASA Chandra Banner

    NASA/Chandra Telescope

    From NASA Chandra

    October 16, 2018
    Media contacts:
    Megan Watzke
    Chandra X-ray Center, Cambridge, Mass.
    617-496-7998
    mwatzke@cfa.harvard.edu

    1
    Credit: X-ray: NASA/CXC/GSFC/UMC/E. Troja et al.; Optical and infrared: NASA/STScI

    NASA/ESA Hubble Telescope

    A source with remarkable similarities to GW170817, the first source identified to emit gravitational waves and light, has been discovered.

    This new object, called GRB 150101B, was first seen as a gamma-ray burst in January 2015.

    Follow-up observations with Chandra and several other telescopes at different wavelengths uncovered common traits between the two objects.

    Chandra images showed how GRB 150101B faded with time, a key piece of information.

    About a year ago, astronomers excitedly reported the first detection of electromagnetic waves, or light, from a gravitational wave source. Now, a year later, researchers are announcing the existence of a cosmic relative to that historic event.

    The discovery was made using data from telescopes including NASA’s Chandra X-ray Observatory, Fermi Gamma-ray Space Telescope, Neil Gehrels Swift Observatory, the NASA Hubble Space Telescope (HST), and the Discovery Channel Telescope (DCT).

    NASA/Fermi LAT


    NASA/Fermi Gamma Ray Space Telescope

    NASA Neil Gehrels Swift Observatory


    Discovery Channel Telescope at Lowell Observatory, Happy Jack AZ, USA, Altitude 2,360 m (7,740 ft)

    The object of the new study, called GRB 150101B, was first reported as a gamma-ray burst detected by Fermi in January 2015. This detection and follow-up observations at other wavelengths show GRB 150101B shares remarkable similarities to the neutron star merger and gravitational wave source discovered by Advanced Laser Interferometer Gravitational Wave Observatory (LIGO) and its European counterpart Virgo in 2017 known as GW170817. The latest study concludes that these two separate objects may, in fact, be related.


    “It’s a big step to go from one detected object to two,” said Eleonora Troja, lead author of the study from NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the University of Maryland at College Park (UMCP). “Our discovery tells us that events like GW170817 and GRB 150101B could represent a whole new class of erupting objects that turn on and off in X-rays and might actually be relatively common.”

    Troja and her colleagues think both GRB 150101B and GW170817 were most likely produced by the same type of event: the merger of two neutron stars, a catastrophic coalescence that generated a narrow jet, or beam, of high-energy particles. The jet produced a short, intense burst of gamma rays (known as a short GRB), a high-energy flash that can last only seconds. GW170817 proved that these events may also create ripples in space-time itself called gravitational waves.

    The apparent match between GRB 150101B and GW170817 is striking: both produced an unusually faint and short-lived gamma ray burst, and both were a source of bright, blue optical light lasting a few days, and X-ray emission lasted much longer. The host galaxies are also remarkably similar, based on Hubble Space Telescope and DCT observations. Both are bright elliptical galaxies with a population of stars a few billion years old and displaying no evidence for new stars forming.

    “We have a case of cosmic look-alikes,” said co-author Geoffrey Ryan of UMCP. “They look the same, act the same and come from similar neighborhoods, so the simplest explanation is that they are from the same family of objects.”

    In the cases of both GRB 150101B and GW170817, the slow rise in the X-ray emission compared to most GRBs implies that the explosion was likely viewed “off-axis,” that is, with the jet not pointing directly towards the Earth. The discovery of GRB150101 represents only the second time astronomers have ever detected an off-axis short GRB.

    While there are many commonalities between GRB 150101B and GW170817, there are two very important differences. One is their location. GW170817 is about 130 million light years from Earth, while GRB 150101B lies about 1.7 billion light years away. Even if Advanced LIGO had been operating in early 2015, it would very likely not have detected gravitational waves from GRB 150101B because of its greater distance.

    “The beauty of GW170817 is that it gave us a set of characteristics, kind of like genetic markers, to identify new family members of explosive objects at even greater distances than LIGO can currently reach,” said co-author Luigi Piro of National Institute for Astrophysics in Rome.

    The optical emission from GB150101B is largely in the blue portion of the spectrum, providing an important clue that this event involved a so-called kilonova, as seen in GW170817. A kilonova is an extremely powerful explosion that not only releases a large amount energy, but may also produce important elements like gold, platinum, and uranium that other stellar explosions do not.

    It is possible that a few mergers like the ones seen in GW170817 and GRB 150101B had been detected as short GRBs before but had not been identified with other telescopes. Without detections at longer wavelengths like X-rays or optical light, GRB positions are not accurate enough to determine what galaxy they are located in.

    In the case of GRB 150101B, astronomers thought at first that the counterpart was an X-ray source detected by Swift in the center of the galaxy, likely from material falling into a supermassive black hole. However, follow-up observations with Chandra detected the true counterpart away from the center of the host galaxy.

    The other important difference between GW170817 and GRB 150101B is that without gravitational wave detection, the team does not know the masses of the two objects that merged. It is possible that the merger was between a black hole and a neutron star, rather than two neutron stars.

    “We need more cases like GW170817 that combine gravitational wave and electromagnetic data to find an example between a neutron star and black hole. Such a detection would be the first of its kind,” said co-author Hendrik Van Eerten of the University of Bath in the United Kingdom. “Our results are encouraging for finding more mergers and making such a detection.”

    A paper describing these results appears in the journal Nature Communications today.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    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.

     
  • richardmitnick 3:22 pm on October 8, 2018 Permalink | Reply
    Tags: , , , , , NASA Chandra,   

    From Ethan Siegel: “The Most Important X-Ray Image Ever Taken Proved The Existence Of Dark Matter” 

    From Ethan Siegel
    Oct 8, 2018

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    NASA Finds Direct Proof of Dark Matter
    For Release: August 21, 2006 from Chandra
    NASA RELEASE 06-297
    The gravitational lensing map (blue), overlayed over the optical and X-ray (pink) data of the Bullet cluster. The mismatch of the locations of the X-rays and the inferred mass is undeniable. (X-RAY: NASA/CXC/CFA/M.MARKEVITCH ET AL.; LENSING MAP: NASA/STSCI; ESO WFI; MAGELLAN/U.ARIZONA/D.CLOWE ET AL.; OPTICAL: NASA/STSCI; MAGELLAN/U.ARIZONA/D.CLOWE ET AL.)

    NASA/Chandra X-ray Telescope

    NASA/ESA Hubble Telescope

    ESO WFI LaSilla 2.2-m MPG/ESO telescope at La Silla, 600 km north of Santiago de Chile at an altitude of 2400 metres


    ESO 2.2 meter telescope 600 km north of Santiago de Chile at Cerro LaSilla, at an altitude of 2400 metres

    Carnegie 6.5 meter Magellan Baade and Clay Telescopes located at Carnegie’s Las Campanas Observatory, Chile. over 2,500 m (8,200 ft) high

    NASA’s Chandra X-ray observatory has shown us the Universe like nothing else ever before.

    When it comes to the Universe, it mainly generates X-rays through high-temperature heating.

    2
    X-rays from Chandra reveal the cluster MACS J0717’s hot gas, while optical data show the individual galaxies in the system. (X-RAY (NASA/CXC/IFA/C. MA ET AL.); OPTICAL (NASA/STSCI/IFA/C. MA ET AL.)

    When matter heats up, through collisions, interactions, acceleration or collapse, it can emit X-rays.

    3
    X-ray emissions that are large, extended, and structure-rich highlight a variety of supernovae seen in the galaxy. Some of these are only a few hundred years old; others are many thousands. A complete absence of X-rays indicates the lack of a supernova. In the early Universe, this was the most common death-mechanism of the first stars. (NASA/CXC/SAO)

    Galaxy clusters, supernova remnants, active galaxies, binary star systems, and even the Moon emit them.

    4
    As seen in X-rays against the cosmic background, the Moon’s illuminated (bright) and non-illuminated portions (dark) are clearly visible in this early X-ray image taken by ROSAT. The X-rays arise mostly from reflected emission from the Sun. (DARA, ESA, MPE, NASA, J.H.M.M. SCHMITT)

    ROSAT X-ray satellite built by DLR , with instruments built by West Germany, the United Kingdom and the United States

    Yet the most important X-ray image of all time was an incredible surprise.

    This is the Bullet Cluster: a system of two galaxy clusters colliding at high speeds.

    5
    The X-ray observations of the Bullet Cluster, as taken by the Chandra X-ray observatory. (NASA/CXC/CFA/M.MARKEVITCH ET AL., FROM MAXIM MARKEVITCH (SAO))

    As the gaseous matter inside collides, it slows, heats up, and lags behind, emitting X-rays.

    6
    Optical images from the Magellan telescope [see above] with overplotted contours of the spatial distribution of mass (left), from gravitational lensing. When you look at those same contours overplotted over Chandra X-ray data that traces hot plasma in a galaxy (right), you can see that the normal matter and the overall effects of mass do not align. (D. CLOWE, M BRADAČ, A. H. GONZALEZ ET AL., APJ (2006))

    However, we can use gravitational lensing to learn where the mass is located in this system.

    The bending and shearing of light from background galaxies shows it’s separated from the matter’s and X-rays’ location.

    7
    Large-field mass reconstruction based on the combined (HST and CFHT) catalogs. On the left-hand side, the mass contours of Abell 520 are overlaid on the smoothed rest-frame luminosity distribution of the cluster. On the right-hand side, the distribution of the high (red) and low (green) velocity groups, corresponding to the multiple mass centers of the cluster. (M.J. JEE ET AL. (2012), THE ASTROPHYSICAL JOURNAL, VOLUME 747, NUMBER 2)

    This separation is some of our strongest evidence for dark matter.

    8
    Three colliding galaxy clusters (and one colliding group, at the lower-left), showing the separation between X-rays (pink) and gravitation (blue), indicative of dark matter. On large scales, cold dark matter is necessary, and no alternative or substitute will do. (X-RAY: NASA/CXC/UVIC./A.MAHDAVI ET AL. OPTICAL/LENSING: CFHT/UVIC./A. MAHDAVI ET AL. (TOP LEFT); X-RAY: NASA/CXC/UCDAVIS/W.DAWSON ET AL.; OPTICAL: NASA/ STSCI/UCDAVIS/ W.DAWSON ET AL. (TOP RIGHT); ESA/XMM-NEWTON/F. GASTALDELLO (INAF/ IASF, MILANO, ITALY)/CFHTLS (BOTTOM LEFT); X-RAY: NASA, ESA, CXC, M. BRADAC (UNIVERSITY OF CALIFORNIA, SANTA BARBARA), AND S. ALLEN (STANFORD UNIVERSITY) (BOTTOM RIGHT))



    CFHT Telescope, Maunakea, Hawaii, USA, at Maunakea, Hawaii, USA,4,207 m (13,802 ft) above sea level

    ESA/XMM Newton

    Since then, over a dozen additional colliding clusters display such a separation, in a variety of configurations.

    9
    The X-ray (pink) and overall matter (blue) maps of various colliding galaxy clusters show a clear separation between normal matter and gravitational effects, some of the strongest evidence for dark matter. Alternative theories now need to be so contrived that they are considered by many to be quite ridiculous. (X-RAY: NASA/CXC/ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE, SWITZERLAND/D.HARVEY NASA/CXC/DURHAM UNIV/R.MASSEY; OPTICAL/LENSING MAP: NASA, ESA, D. HARVEY (ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE, SWITZERLAND) AND R. MASSEY (DURHAM UNIVERSITY, UK))

    Whatever dark matter is, it cannot be accounted for by the Universe’s normal matter alone.

    10
    The large-scale clustering data (dots) and the prediction of a Universe with 85% dark matter and 15% normal matter (solid line) match up incredibly well. The lack of a cutoff indicates the temperature (and coldness) of dark matter; the magnitude of the wiggles indicates the ratio of normal matter to dark matter; the fact that the curve is largely smooth and doesn’t have spontaneous drops down to zero amplitude rules out a normal-matter-only Universe. (L. ANDERSON ET AL. (2012), FOR THE SLOAN DIGITAL SKY SURVEY)

    The Bullet Cluster images were the first to demonstrate this effect.

    11
    The colliding galaxy cluster “El Gordo,” the largest one known in the observable Universe, showing the same evidence of dark matter as other colliding clusters. It is possible to explain El Gordo with new physics, but this is an unnecessary complication; standard collisionless dark matter does just fine here, as it does for all of the colliding clusters. (NASA, ESA, J. JEE (UNIV. OF CALIFORNIA, DAVIS), J. HUGHES (RUTGERS UNIV.), F. MENANTEAU (RUTGERS UNIV. & UNIV. OF ILLINOIS, URBANA-CHAMPAIGN), C. SIFON (LEIDEN OBS.), R. MANDELBUM (CARNEGIE MELLON UNIV.), L. BARRIENTOS (UNIV. CATOLICA DE CHILE), AND K. NG (UNIV. OF CALIFORNIA, DAVIS))

    NASA’s Chandra, which took the image, has been rightfully renewed as NASA’s flagship X-ray observatory after 19 continuous years.

    12
    Artist illustration of the Chandra X-ray Observatory. Chandra is the most sensitive X-ray telescope ever built, and has just been extended through at least 2024 as the flagship X-ray observatory in the NASA arsenal. (NASA/CXC/NGST TEAM)

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

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

     
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