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  • richardmitnick 1:53 pm on January 5, 2016 Permalink | Reply
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    From NASA NuSTAR: “Andromeda Galaxy Scanned with High-Energy X-ray Vision” 

    NASA NuSTAR
    NuSTAR

    1

    January 5, 2016
    No writer credit found

    NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, has captured the best high-energy X-ray view yet of a portion of our nearest large, neighboring galaxy, Andromeda. The space mission has observed 40 X-ray binaries — intense sources of X-rays comprised of a black hole or neutron star that feeds off a stellar companion.

    The results will ultimately help researchers better understand the role of X-ray binaries in the evolution of our universe. According to astronomers, these energetic objects may play a critical role in heating the intergalactic bath of gas in which the very first galaxies formed.

    “Andromeda is the only large spiral galaxy where we can see individual X-ray binaries and study them in detail in an environment like our own,” said Daniel Wik of NASA Goddard Space Flight Center in Greenbelt, Maryland, who presented the results at the 227th meeting of American Astronomical Society in Kissimmee, Florida. “We can then use this information to deduce what’s going on in more distant galaxies, which are harder to see.”

    Andromeda, also known as M31, can be thought of as the big sister to our own Milky Way galaxy. Both galaxies are spiral in shape, but Andromeda is slightly larger than the Milky Way in size. Lying 2.5 million light-years away, Andromeda is relatively nearby in cosmic terms. It can even be seen by the naked eye in dark, clear skies. [It is not mentioned here, but Andromeda and the Milky Way are apparently destined to merge in the distant future.]

    Other space missions, such as NASA’s Chandra X-ray Observatory, have obtained crisper images of Andromeda at lower X-ray energies than the high-energy X-rays detected by NuSTAR.

    NASA Chandra Telescope
    NASA/Chandra

    The combination of Chandra and NuSTAR provides astronomers with a powerful tool for narrowing in on the nature of the X-ray binaries in spiral galaxies.

    In X-ray binaries, one member is always a dead star or remnant formed from the explosion of what was once a star much more massive than the sun. Depending on the mass and other properties of the original giant star, the explosion may produce either a black hole or neutron star. Under the right circumstances, material from the companion star can “spill over” its outermost edges and then be caught by the gravity of the black hole or neutron star. As the material falls in, it is heated to blazingly high temperatures, releasing a huge amount of X-rays.

    With NuSTAR’s new view of a swath of Andromeda, Wik and colleagues are working on identifying the fraction of X-ray binaries harboring black holes versus neutron stars. That research will help them understand the population as a whole.

    “We have come to realize in the past few years that it is likely the lower-mass remnants of normal stellar evolution, the black holes and neutron stars, may play a crucial role in heating of the intergalactic gas at very early times in the universe, around the cosmic dawn,” said Ann Hornschemeier of NASA Goddard, the principal investigator of the NuSTAR Andromeda studies.

    “Observations of local populations of stellar-mass-sized black holes and neutron stars with NuSTAR allow us to figure out just how much power is coming out from these systems.”

    The new research also reveals how Andromeda may differ from our Milky Way. Fiona Harrison, the principal investigator of the NuSTAR mission, added, “Studying the extreme stellar populations in Andromeda tells us about how its history of forming stars may be different than in our neighborhood.”

    Harrison will be presenting the 2015 Rossi Prize lecture at the AAS meeting. The prize, awarded by the AAS’s High-Energy Astrophysics Division, honors physicist Bruno Rossi, an authority on cosmic-ray physics and a pioneer in the field of X-ray astronomy.

    See the full article here .

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    NuSTAR is a Small Explorer mission led by the California Institute of Technology in Pasadena and managed by NASA’s Jet Propulsion Laboratory, also in Pasadena, for NASA’s Science Mission Directorate in Washington. The spacecraft was built by Orbital Sciences Corporation, Dulles, Va. Its instrument was built by a consortium including Caltech; JPL; the University of California, Berkeley ; Columbia University, New York; NASA’s Goddard Space Flight Center, Greenbelt, Md.; the Danish Technical University in Denmark; Lawrence Livermore National Laboratory, Livermore, Calif.; ATK Aerospace Systems, Goleta, Calif., and with support from the Italian Space Agency (ASI) Science Data Center.

    NuSTAR’s mission operations center is at UC Berkeley, with the ASI providing its equatorial ground station located at Malindi, Kenya. The mission’s outreach program is based at Sonoma State University, Rohnert Park, Calif. NASA’s Explorer Program is managed by Goddard. JPL is managed by Caltech for NASA.

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 8:33 pm on December 17, 2015 Permalink | Reply
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    From JPL-Caltech: “NuSTAR Finds Cosmic Clumpy Doughnut Around Black Hole” 

    JPL-Caltech

    December 17, 2015
    Whitney Clavin
    Jet Propulsion Laboratory, Pasadena, California
    818-354-4673
    whitney.clavin@jpl.nasa.gov

    1
    Galaxy NGC 1068 can be seen in close-up in this view from NASA’s Hubble Space Telescope.

    NASA Hubble Telescope
    NASA/ESA Hubble

    NuSTAR’s high-energy X-rays eyes were able to obtain the best view yet into the hidden lair of the galaxy’s central, supermassive black hole.

    NASA NuSTAR
    NASA/NuSTAR

    2
    This active black hole is one of the most obscured known, meaning that it is surrounded by extremely thick clouds of gas and dust.

    The NuSTAR data revealed that the torus of gas and dust surrounding the black hole, also referred to as a doughnut, is more clumpy than previously thought. doughnuts around active, supermassive black holes were originally proposed in the mid-1980s to be smooth entities. More recently, researchers have been finding that doughnuts are not so smooth but have lumps. NuSTAR’s latest finding shows that this is true for even the thickest of doughnuts.

    NuSTAR is a Small Explorer mission led by the California Institute of Technology in Pasadena and managed by NASA’s Jet Propulsion Laboratory, also in Pasadena, for NASA’s Science Mission Directorate in Washington. The spacecraft was built by Orbital Sciences Corporation, Dulles, Virginia. Its instrument was built by a consortium including Caltech; JPL; the University of California, Berkeley; Columbia University, New York; NASA’s Goddard Space Flight Center, Greenbelt, Maryland; the Danish Technical University in Denmark; Lawrence Livermore National Laboratory, Livermore, California; ATK Aerospace Systems, Goleta, California, and with support from the Italian Space Agency (ASI) Science Data Center.

    NuSTAR’s mission operations center is at UC Berkeley, with the ASI providing its equatorial ground station located at Malindi, Kenya. The mission’s outreach program is based at Sonoma State University, Rohnert Park, California. NASA’s Explorer Program is managed by Goddard. JPL is managed by Caltech for NASA.

    For more information, visit http://www.nasa.gov/nustar and http://www.nustar.caltech.edu/.

    The most massive black holes in the universe are often encircled by thick, doughnut-shaped disks of gas and dust. This deep-space doughnut material ultimately feeds and nourishes the growing black holes tucked inside.

    Until recently, telescopes weren’t able to penetrate some of these doughnuts, also known as tori.

    “Originally, we thought that some black holes were hidden behind walls or screens of material that could not be seen through,” said Andrea Marinucci of the Roma Tre University in Italy, lead author of a new Monthly Notices of the Royal Astronomical Society study describing results from NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, and the European Space Agency’s XMM-Newton space observatory.

    With its X-ray vision, NuSTAR recently peered inside one of the densest of these doughnuts known to surround a supermassive black hole. This black hole lies at the center of a well-studied spiral galaxy called NGC 1068, located 47 million light-years away in the Cetus constellation.

    The observations revealed a clumpy, cosmic doughnut.

    “The rotating material is not a simple, rounded doughnut as originally thought, but clumpy,” said Marinucci.

    Doughnut-shaped disks of gas and dust around supermassive black holes were first proposed in the mid-1980s to explain why some black holes are hidden behind gas and dust, while others are not. The idea is that the orientation of the doughnut relative to Earth affects the way we perceive a black hole and its intense radiation. If the doughnut is viewed edge-on, the black hole is blocked. If the doughnut is viewed face-on, the black hole and its surrounding, blazing materials can be detected. This idea is referred to as the unified model because it neatly joins together the different black hole types, based solely upon orientation.

    In the past decade, astronomers have been finding hints that these doughnuts aren’t as smoothly shaped as once thought. They are more like defective, lumpy doughnuts that a doughnut shop might throw away.

    The new discovery is the first time this clumpiness has been observed in an ultra-thick doughnut, and supports the idea that this phenomenon may be common. The research is important for understanding the growth and evolution of massive black holes and their host galaxies.

    “We don’t fully understand why some supermassive black holes are so heavily obscured, or why the surrounding material is clumpy,” said co-author Poshak Gandhi of the University of Southampton in the United Kingdom. “This is a subject of hot research.”

    Both NuSTAR and [ESA]XMM-Newton observed the supermassive black hole in NGC 1068 simultaneously on two occasions between 2014 to 2015.

    ESA XMM Newton
    ESA/XMM-Newton

    On one of those occasions, in August 2014, NuSTAR observed a spike in brightness. NuSTAR observes X-rays in a higher-energy range than XMM-Newton, and those high-energy X-rays can uniquely pierce thick clouds around the black hole. The scientists say the spike in high-energy X-rays was due to a clearing in the thickness of the material entombing the supermassive black hole.

    “It’s like a cloudy day, when the clouds partially move away from the sun to let more light shine through,” said Marinucci.

    NGC 1068 is well known to astronomers as the first black hole to give birth to the unification idea. “But it is only with NuSTAR that we now have a direct glimpse of its black hole through such clouds, albeit fleeting, allowing a better test of the unification concept,” said Marinucci.

    The team says that future research will address the question of what causes the unevenness in doughnuts. The answer could come in many flavors. It’s possible that a black hole generates turbulence as it chomps on nearby material. Or, the energy given off by young stars could stir up turbulence, which would then percolate outward through the doughnut. Another possibility is that the clumps may come from material falling onto the doughnut. As galaxies form, material migrates toward the center, where the density and gravity is greatest. The material tends to fall in clumps, almost like a falling stream of water condensing into droplets as it hits the ground.

    “We’d like to figure out if the unevenness of the material is being generated from outside the doughnut, or within it,” said Gandhi.

    “These coordinated observations with NuSTAR and XMM-Newton show yet again the exciting science possible when these satellites work together,” said Daniel Stern, NuSTAR project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California.

    See the full article here.

    Another simpler view of NGC 1068 from Hubble:
    4

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 10:59 am on November 27, 2015 Permalink | Reply
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    From JPL-Caltech: “NASA, ESA Telescopes Give Shape to Furious Black Hole Winds” 

    JPL-Caltech

    February 19, 2015
    Whitney Clavin
    Jet Propulsion Laboratory, Pasadena, California
    818-354-4673
    whitney.clavin@jpl.nasa.gov

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

    1
    Supermassive black holes at the cores of galaxies blast radiation and ultra-fast winds outward, as illustrated in this artist’s conception. New data from NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) and the European Space Agency’s (ESA’s) XMM-Newton telescopes show that these winds, which contain gases of highly ionized atoms, blow in a nearly spherical fashion, emanating in every direction, as shown in the artwork. The findings rule out the possibility that the winds blow in narrow beams.

    NASA NuSTAR
    NASA/NuSTAR

    ESA XMM Newton
    ESA/XMM-Newton

    With the shape and extent of the winds known, the researchers were able to determine the winds’ strength. The high-speed winds are powerful enough to shut down star formation throughout a galaxy.

    The artwork is based on an image of the Pinwheel galaxy (Messier 101) taken by NASA’s Hubble Space Telescope.

    NASA Hubble Telescope
    NASA/ESA Hubble

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    The galaxy Messier 101 (M101, also known as NGC 5457 and also nicknamed the Pinwheel Galaxy) lies in the northern circumpolar constellation, Ursa Major (The Great Bear), at a distance of about 21 million light-years from Earth. This is one of the largest and most detailed photo of a spiral galaxy that has been released from Hubble. The galaxy’s portrait is actually composed of 51 individual Hubble exposures, in addition to elements from images from ground-based photos [CFHT image: Canada-France-Hawaii Telescope/J.-C. Cuillandre/Coelum NOAO image: George Jacoby, Bruce Bohannan, Mark Hanna/NOAO/AURA/NSF.

    NuSTAR’s mission operations center is at UC Berkeley, with the ASI providing its equatorial ground station located at Malindi, Kenya. The mission’s outreach program is based at Sonoma State University, Rohnert Park, California. NASA’s Explorer Program is managed by Goddard. JPL is managed by Caltech for NASA.

    2
    This plot of data from two space telescopes, NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) and the European Space Agency’s (ESA’s) XMM-Newton determines for the first time the shape of ultra-fast winds from supermassive black holes, or quasars. The winds blow in every direction, in a nearly spherical fashion, coming from both sides of a galaxy (only one side is shown here).

    The plot shows the brightness of X-ray light from an extremely luminous quasar called PDS 456, with the highest-energy rays on the right. XMM-Newton sees lower-energy X-rays, and NuSTAR, higher. XMM Newton had previously observed the extremely luminous quasar, called PDS 456, on its own in 2001. At that time, it had measured the X-rays up to an energy level of 11 kiloelectron volts. From those data, researchers detected a dip in the X-ray light, called an absorption feature (see dip in plot). The dip is caused by iron atoms — which are carried by the winds along with other matter — absorbing the X-ray light of a particular energy. What’s more, the absorption feature is ‘blueshifted,” meaning that the winds are speeding toward us (like a train’s whistle shifting to higher frequencies as it races toward you).

    In other words, the 2001 XMM-Newton data had told researchers that at least some of the winds were blowing toward us — but they didn’t reveal whether those winds were confined to a narrow beam along our line of sight, or were blowing in all directions. That’s because XMM-Newton had only detected absorption features, which by definition occur in front of a light source, in this case, the quasar. To probe what was happening to at sides of the quasar, the astronomers needed to find a different type of feature called an emission feature. These occur when iron scatters X-ray light at a particular energy in all directions, not only toward the observer.

    Enter NuSTAR to the X-ray astronomy scene, a high-energy X-ray telescope that was launched in 2012. NuSTAR and XMM-Newton teamed up to observe PDS 456 simultaneously in 2013 and 2014. The results are shown in this plot. NuSTAR data are represented as orange circles and XMM-Newton as blue squares. The NuSTAR data reveal the baseline of the “continuum” quasar light (see gray line) — or what the quasar would look like without any winds. What stands out is the bump to the left of the dips. That’s an iron emission signature, the telltale sign that the black hole winds blow to the sides and in all directions.

    XMM-Newton might have seen the emission feature before, but the feature couldn’t be identified until NuSTAR’s elucidated the baseline quasar light. For example, had the X-ray winds been confined to a beam, then NuSTAR would have seen more brightness at the higher end of the X-ray spectrum, and there would have been no iron emission feature.

    The results demonstrate that, in some cases, two telescopes are better than one at solving tricky problems. By observing the entire X-ray energy range, the astronomers were able to get a more complete picture of what is happening around the quasar.

    “We know black holes in the centers of galaxies can feed on matter, and this process can produce winds. This is thought to regulate the growth of the galaxies,” said Fiona Harrison of the California Institute of Technology (Caltech) in Pasadena, California. Harrison is the principal investigator of NuSTAR and a co-author on a new paper about these results appearing in the journal Science. “Knowing the speed, shape and size of the winds, we can now figure out how powerful they are.”

    Supermassive black holes blast matter into their host galaxies, with X-ray-emitting winds traveling at up to one-third the speed of light. In the new study, astronomers determined PDS 456, an extremely bright black hole known as a quasar more than 2 billion light-years away, sustains winds that carry more energy every second than is emitted by more than a trillion suns.

    “Now we know quasar winds significantly contribute to mass loss in a galaxy, driving out its supply of gas, which is fuel for star formation,” said the study’s lead author, Emanuele Nardini of Keele University in England.

    “This is a great example of the synergy between XMM-Newton and NuSTAR,” said Norbert Schartel, XMM-Newton project scientist at ESA. “The complementarity of these two X-ray observatories is enabling us to unveil previously hidden details about the powerful side of the universe.”

    “For an astronomer, studying PDS 456 is like a paleontologist being given a living dinosaur to study,” said study co-author Daniel Stern of NASA’s Jet Propulsion Laboratory in Pasadena. “We are able to investigate the physics of these important systems with a level of detail not possible for those found at more typical distances, during the ‘Age of Quasars.'”

    NuSTAR is a Small Explorer mission led by Caltech and managed by JPL for NASA’s Science Mission Directorate in Washington.

    For more information, visit http://www.nasa.gov/nustar and http://www.nustar.caltech.edu/.

    See the full article here .

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    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 2:37 pm on October 10, 2015 Permalink | Reply
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    From RAS: “Universe’s hidden supermassive black holes revealed” From July but Well Worth Your Time 

    Royal Astronomical Society

    Royal Astronomical Society

    09 July 2015
    Dr Robert Massey
    Royal Astronomical Society
    Mob: +44 (0)794 124 8035
    rm@ras.org.uk

    Ms Anita Heward
    Royal Astronomical Society
    Mob: +44 (0)7756 034 243
    anitaheward@btinternet.com

    Dr Sam Lindsay
    Royal Astronomical Society
    Mob: +44 (0)7957 566 861
    sl@ras.org.uk

    Durham University Marketing and Communications Office
    Tel: +44 (0)191 334 6075
    communications.team@durham.ac.uk

    Astronomers have found evidence for a large population of hidden supermassive black holes in the Universe. Using NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) satellite observatory, the team of international scientists detected the high-energy x-rays from five supermassive black holes previously clouded from direct view by dust and gas. The findings were presented today at the Royal Astronomical Society’s National Astronomy Meeting, at Venue Cymru, in Llandudno, Wales (Monday 6 July).

    1
    NASA/Nu-STAR Credit: NASA/JPL-Caltech.

    The research, led by astronomers at Durham University, UK, supports the theory that potentially millions more supermassive black holes exist in the Universe, but are hidden from view.

    The scientists pointed NuSTAR at nine candidate hidden supermassive black holes that were thought to be extremely active at the centre of galaxies, but where the full extent of this activity was potentially obscured from view.

    High-energy x-rays found for five of the black holes confirmed that they had been hidden by dust and gas. The five were much brighter and more active than previously thought as they rapidly feasted on surrounding material and emitted large amounts of radiation.

    3
    A Hubble Space Telescope colour image of one of the nine galaxies targeted by NuSTAR. The high energy X-rays detected by NuSTAR revealed the presence of an extremely active supermassive black hole at the galaxy centre, deeply buried under a blanket of gas and dust. Credit: Hubble Legacy Archive, NASA, ESA.

    NASA Hubble Telescope
    NASA/ESA Hubble

    Such observations were not possible before NuSTAR, which launched in 2012 and is able to detect much higher energy x-rays than previous satellite observatories.

    Lead author George Lansbury, a postgraduate student in the Centre for Extragalactic Astronomy, at Durham University, said: “For a long time we have known about supermassive black holes that are not obscured by dust and gas, but we suspected that many more were hidden from our view.

    “Thanks to NuSTAR for the first time we have been able to clearly see these hidden monsters that are predicted to be there, but have previously been elusive because of their ‘buried’ state.

    “Although we have only detected five of these hidden supermassive black holes, when we extrapolate our results across the whole Universe then the predicted numbers are huge and in agreement with what we would expect to see.”

    Daniel Stern, the project scientist for NuSTAR at NASA’s Jet Propulsion Laboratory in Pasadena, California, added: “High-energy X-rays are more penetrating than low-energy X-rays, so we can see deeper into the gas burying the black holes. NuSTAR allows us to see how big the hidden monsters are and is helping us learn why only some black holes appear obscured.”

    The research was funded by the Science and Technology Facilities Council (STFC) and has been accepted for publication in The Astrophysical Journal.

    4
    An artist’s illustration of a supermassive black hole, actively feasting on its surroundings. The central black hole is hidden from direct view by a thick layer of encircling gas and dust.

    See the full article here .

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    The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science.

     
  • richardmitnick 4:11 pm on July 6, 2015 Permalink | Reply
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    From JPL: “NuSTAR Stares Deep into Hidden Lairs of Black Holes” 

    JPL

    July 6, 2015
    Whitney Clavin
    Jet Propulsion Laboratory, Pasadena, California
    818-354-4673
    whitney.clavin@jpl.nasa.gov

    1
    Top: An illustration of NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, in orbit. The unique school bus-long mast allows NuSTAR to focus high energy X-rays.

    Lower-left: A color image from NASA’s Hubble Space Telescope of one of the nine galaxies targeted by NuSTAR in search of hidden black holes.

    Bottom-right: An artist’s illustration of a supermassive black hole, actively feasting on its surroundings. The central black hole is hidden from direct view by a thick layer of encircling gas and dust.

    Some of the “biggest and baddest” black holes around are buried under thick blankets of gas and dust. These monsters in the middle of galaxies are actively devouring material, but their hidden nature makes observing them a challenge.

    NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) recently caught a glimpse of five of these secluded beasts. While hidden from view from most other telescopes, NuSTAR can spot them by detecting the highest-energy X-rays, which can penetrate through the enshrouding gas and dust.

    The research, led by astronomers at Durham University, United Kingdom, supports the theory that potentially millions of supermassive black holes exist in the universe hidden from view. The findings were presented today, July 6, at the Royal Astronomical Society’s National Astronomy Meeting in Llandudno, Wales.

    The scientists pointed NuSTAR at nine galaxies where supermassive black holes were thought to be extremely active but largely obscured. Five of these candidates were found to contain hidden supermassive black holes, feasting on surrounding material. What’s more, the objects were observed to be more active than previously thought.

    Such observations were not possible before NuSTAR, which launched in 2012 and is able to detect much higher-energy X-rays than previous satellite observatories.

    “Thanks to NuSTAR, for the first time, we have been able to clearly identify these hidden monsters that are predicted to be there, but have previously been elusive because of their surrounding cocoons of material,” said George Lansbury of Durham University, lead author of the findings accepted for publication in The Astrophysical Journal.

    “Although we have only detected five of these hidden supermassive black holes, when we extrapolate our results across the whole universe, then the predicted numbers are huge and in agreement with what we would expect to see.”

    Daniel Stern, the project scientist for NuSTAR at NASA’s Jet Propulsion Laboratory in Pasadena, California, added: “High-energy X-rays are more penetrating than low-energy X-rays, so we can see deeper into the gas burying the black holes. NuSTAR allows us to see how big the hidden monsters are, and is helping us learn why only some black holes appear obscured.”

    The research is funded by the Science and Technology Facilities Council.

    NuSTAR is a Small Explorer mission led by the California Institute of Technology in Pasadena and managed by NASA’s Jet Propulsion Laboratory, also in Pasadena, for NASA’s Science Mission Directorate in Washington. The spacecraft was built by Orbital Sciences Corporation, Dulles, Virginia.

    For more information, visit:

    http://www.nasa.gov/nustar

    http://www.nustar.caltech.edu

    See the full article here.

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge, on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 6:29 pm on May 7, 2015 Permalink | Reply
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    From JPL: “Star Explosion is Lopsided, Finds NASA’s NuSTAR” 

    JPL

    May 7, 2015
    Whitney Clavin
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-4673
    whitney.clavin@jpl.nasa.gov

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

    1
    Supernova SN 1987A, one of the brightest stellar explosions since the invention of the telescope more than 400 years ago, is no stranger to the NASA/ESA Hubble Space Telescope. The observatory has been on the frontline of studies into this brilliant dying star since its launch in 1990, three years after the supernova exploded on 23 February 1987. This image of Hubble’s old friend, retreived from the telescope’s data archive, may be the best ever of this object, and reminds us of the many mysteries still surrounding it. Dominating this picture are two glowing loops of stellar material and a very bright ring surrounding the dying star at the centre of the frame. Although Hubble has provided important clues on the nature of these structures, their origin is still largely unknown. Another mystery is that of the missing neutron star. The violent death of a high-mass star, such as SN 1987A, leaves behind a stellar remnant — a neutron star or a black hole. Astronomers expect to find a neutron star in the remnants of this supernova, but they have not yet been able to peer through the dense dust to confirm it is there. The supernova belongs to the Large Magellanic Cloud, a nearby galaxy about 168 000 light-years away.

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    Large Magellanic Cloud

    Even though the stellar explosion took place around 166 000 BC, its light arrived here less than 25 years ago. This picture is based on observations done with the High Resolution Channel of Hubble’s Advanced Camera for Surveys [ACS].

    NASA Hubble ACS
    ACS

    The field of view is approximately 25 by 25 arcseconds. Credit: NASA/ESA Hubble

    2
    The plot of data from NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR (right), amounts to a “smoking gun” of evidence in the mystery of how massive stars explode. The observations indicate that supernovae belonging to a class called Type II or core-collapse blast apart in a lopsided fashion, with the core of the star hurtling in one direction, and the ejected material mostly expanding the other way (see diagram in Figure 1). NuSTAR made the most precise measurements yet of a radioactive element, called titanium-44, in the supernova remnant called 1987A. NuSTAR sees high-energy X-rays, as shown here in the plot ranging from 60 to more than 80 kiloelectron volts. The spectral signature of titanium-44 is apparent as the two tall peaks. The white line shows where one would expect to see these spectral signatures if the titanium were not moving. The fact that the spectral peaks have shifted to lower energies indicates that the titanium has “redshifted,” and is moving way from us. This is similar to what happens to a train’s whistle as the train leaves the station. The whistle’s sound shifts to lower frequencies. NuSTAR’s detection of redshifted titanium reveals that the bulk of material ejected in the 1987A supernova is flying way from us at a velocity of 1.6 million miles per hour (2.6 million kilometers per hour). Had the explosion been spherical in nature, the titanium would have been seen flying uniformly in all directions. This is proof that this explosion occurred in an asymmetrical fashion.

    The still unraveling remains of supernova 1987A are shown here in this image taken by NASA’s Hubble Space Telescope.

    NASA Hubble Telescope
    NASA/ESA Hubble

    The bright ring consists of material ejected from the dying star before it detonated. The ring is being lit up by the explosion’s shock wave.
    NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, has found evidence that a massive star exploded in a lopsided fashion, sending ejected material flying in one direction and the core of the star in the other.

    NASA NuSTAR
    NuSTAR

    The findings offer the best proof yet that star explosions of this type, called Type II or core-collapse supernovae, are inherently asymmetrical, a phenomenon that had been difficult to prove before now.

    “Stars are spherical objects, but apparently the process by which they die causes their cores to be turbulent, boiling and sloshing around in the seconds before their demise,” said Steve Boggs of the University of California, Berkeley, lead author of a new study on the findings, appearing in the May 8 issue of Science. “We are learning that this sloshing leads to asymmetrical explosions.”

    The supernova remnant in the study, called 1987A, is 166,000 light-years away. Light from the blast that created the remnant lit up skies above Earth in 1987. While other telescopes had found hints that this explosion was not spherical, NuSTAR found the “smoking gun” in the form of a radioisotope called titanium-44.

    “Titanium is produced in the very heart of the explosion, so it traces the shape of the engine driving the disassembly of the star,” said Fiona Harrison, the principal investigator of NuSTAR at the California Institute of Technology in Pasadena. “By looking at the shift of the energy of the X-rays coming from titanium, the NuSTAR data revealed that, surprisingly, most of the material is moving away from us.”

    Last year, NuSTAR created detailed titanium-44 maps of another supernova remnant, called Cassiopeia A, also finding evidence of an asymmetrical explosion, though not to as great an extent as in 1987A.

    c
    A false color image of Cassiopeia A (Cas A) using observations from both the Hubble and Spitzer telescopes as well as the Chandra X-ray Observatory (cropped). Date 9 June 2005

    NASA Spitzer Telescope
    Spitzer

    NASA Chandra Telescope
    Chandra

    Together, these results suggest that lopsidedness is at the very root of core-collapse supernova.

    When supernova 1987A first lit up our skies decades ago, telescopes around the world had a unique opportunity to watch the event unfold and evolve. Outer, ejected materials lit up first, followed by the innermost materials powered by radioactive isotopes, such as cobalt-56, which decayed into iron-56. In 2012, the European Space Agency’s Integral satellite detected titanium-44 in 1987A. Titanium-44 continues to blaze in the supernova remnant due to its long lifetime of 85 years.

    ESA Integral
    ESA/Integral

    “In some ways, it is as if 1987A is still exploding in front of our eyes,” said Boggs.

    NuSTAR brought a new tool to the study of 1987A. Thanks to the observatory’s sharp high-energy X-ray vision, it has made the most precise measurements of titanium-44 yet. This radioactive material is produced at the core of a supernova, so it provides astronomers with a direct probe into the mechanisms of a detonating star.

    The NuSTAR spectral data reveal that titanium-44 is moving away from us with a velocity of 1.6 million mph (2.6 million kilometers per hour). That indicates ejected material flung outward in one direction, while the compact core of the supernova, called a neutron star, seems to have kicked off in the opposite direction.

    “These explosions are driven by the formation of a compact object, the remaining core of the star, and this seems to be connected to the core blasting one direction, and the ejected material, the other,” said Boggs.

    Previous observations have hinted at the lopsided nature of supernova blasts, but it was impossible to confirm. Telescopes like NASA’s Chandra X-ray Observatory, which sees lower-energy X-rays than NuSTAR, had spotted iron that had been heated in the 1987A blast, but it was not clear if the iron was generated in the explosion or just happened to have been in the vicinity.

    “Radioactive titanium-44 glows in the X-rays no matter what and is only produced in the explosion,” said Brian Grefenstette, a co-author of the study at Caltech. “This means that we don’t have to worry about how the environment influenced the observations. We are able to directly observe the material ejected in the explosion.”

    Future studies by NuSTAR and other telescopes should further illuminate the warped nature of supernovae. Is 1987A particularly askew, or in line with other objects in its class? A decades-old mystery continues to unravel before our eyes.

    NuSTAR is a Small Explorer mission led by the California Institute of Technology in Pasadena and managed by NASA’s Jet Propulsion Laboratory, also in Pasadena, for NASA’s Science Mission Directorate in Washington.

    For more information, visit:

    http://www.nasa.gov/nustar

    See the full article here.

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 1:40 pm on April 29, 2015 Permalink | Reply
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    From NASA NuSTAR: “NASA’s NuSTAR Captures Possible ‘Screams’ from Zombie Stars” 

    NASA NuSTAR
    NuSTAR

    April 29, 2015
    Felicia Chou
    Headquarters, Washington
    202-358-0257
    felicia.chou@nasa.gov

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

    1
    NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, has captured a new high-energy X-ray view (magenta) of the bustling center of our Milky Way galaxy. The smaller circle shows the area where the NuSTAR image was taken — the very center of our galaxy, where a giant black hole resides. That region is enlarged to the right, in the larger circle, to show the NuSTAR data.
    The NuSTAR picture is one of the most detailed ever taken of the center of our galaxy in high-energy X-rays. The X-ray light, normally invisible to our eyes, has been assigned the color magenta. The brightest point of light near the center of the X-ray picture is coming from a spinning dead star, known as a pulsar, which is near the giant black hole. While the pulsar’s X-ray emissions were known before, scientists were surprised to find more high-energy X-rays than predicted in the surrounding regions, seen here as the elliptical haze. Astronomers aren’t sure what the sources of the extra X-rays are, but one possibility is a population of dead stars. The background picture was captured in infrared light by NASA’s Spitzer Space Telescope.
    The NuSTAR image has an X-ray energy range of 20 to 40 kiloelectron volts.
    Image credit: NASA/JPL-Caltech

    Peering into the heart of the Milky Way galaxy, NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) has spotted a mysterious glow of high-energy X-rays that, according to scientists, could be the “howls” of dead stars as they feed on stellar companions.

    “We can see a completely new component of the center of our galaxy with NuSTAR’s images,” said Kerstin Perez of Columbia University in New York, lead author of a new report on the findings in the journal Nature. “We can’t definitively explain the X-ray signal yet — it’s a mystery. More work needs to be done.”

    The center of our Milky Way galaxy is bustling with young and old stars, smaller black holes and other varieties of stellar corpses – all swarming around a supermassive black hole called Sagittarius A*.

    2
    Sagittarius A*. This image was taken with NASA’s Chandra X-Ray Observatory. Ellipses indicate light echoes.

    NASA Chandra Telescope
    Chandra

    NuSTAR, launched into space in 2012, is the first telescope capable of capturing crisp images of this frenzied region in high-energy X-rays. The new images show a region around the supermassive black hole about 40 light-years across. Astronomers were surprised by the pictures, which reveal an unexpected haze of high-energy X-rays dominating the usual stellar activity.

    “Almost anything that can emit X-rays is in the galactic center,” said Perez. “The area is crowded with low-energy X-ray sources, but their emission is very faint when you examine it at the energies that NuSTAR observes, so the new signal stands out.”

    Astronomers have four potential theories to explain the baffling X-ray glow, three of which involve different classes of stellar corpses. When stars die, they don’t always go quietly into the night. Unlike stars like our sun, collapsed dead stars that belong to stellar pairs, or binaries, can siphon matter from their companions. This zombie-like “feeding” process differs depending on the nature of the normal star, but the result may be an eruption of X-rays.

    According to one theory, a type of stellar zombie called a pulsar could be at work. Pulsars are the collapsed remains of stars that exploded in supernova blasts. They can spin extremely fast and send out intense beams of radiation. As the pulsars spin, the beams sweep across the sky, sometimes intercepting the Earth, like lighthouse beacons.

    “We may be witnessing the beacons of a hitherto hidden population of pulsars in the galactic center,” said co-author Fiona Harrison of the California Institute of Technology (Caltech) in Pasadena, and principal investigator of NuSTAR. “This would mean there is something special about the environment in the very center of our galaxy.”

    Other possible culprits include heavy-set stellar corpses called white dwarfs, which are the collapsed, burned-out remains of stars not massive enough to explode in supernovae. Our sun is such a star, and is destined to become a white dwarf in about five billion years. Because these white dwarfs are much denser than they were in their youth, they have stronger gravity and can produce higher-energy X-rays than normal. Another theory points to small black holes that slowly feed off their companion stars, radiating X-rays as material plummets down into their bottomless pits.

    Alternatively, the source of the high-energy X-rays might not be stellar corpses at all, astronomers say, but rather a diffuse haze of charged particles, called cosmic rays. The cosmic rays might originate from the supermassive black hole at the center of the galaxy as it devours material. When the cosmic rays interact with surrounding, dense gas, they emit X-rays.

    However, none of these theories match what is known from previous research, leaving the astronomers largely stumped.

    “This new result just reminds us that the galactic center is a bizarre place,” said co-author Chuck Hailey of Columbia University. “In the same way people behave differently walking on the street instead of jammed on a crowded rush hour subway, stellar objects exhibit weird behavior when crammed in close quarters near the supermassive black hole.”

    The team says more observations are planned. Until then, theorists will be busy exploring the above scenarios or coming up with new models to explain what could be giving off the puzzling high-energy X-ray glow.

    “Every time that we build small telescopes like NuSTAR, which improve our view of the cosmos in a particular wavelength band, we can expect surprises like this,” said Paul Hertz, the astrophysics division director at NASA Headquarters in Washington.

    NuSTAR is a Small Explorer mission led by Caltech and managed by NASA’s Jet Propulsion Laboratory in Pasadena, California, for NASA’s Science Mission Directorate in Washington.

    More information is online at:

    http://www.nasa.gov/nustar

    See the full article here.

    Please help promote STEM in your local schools.

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    NuSTAR is a Small Explorer mission led by the California Institute of Technology in Pasadena and managed by NASA’s Jet Propulsion Laboratory, also in Pasadena, for NASA’s Science Mission Directorate in Washington. The spacecraft was built by Orbital Sciences Corporation, Dulles, Va. Its instrument was built by a consortium including Caltech; JPL; the University of California, Berkeley ; Columbia University, New York; NASA’s Goddard Space Flight Center, Greenbelt, Md.; the Danish Technical University in Denmark; Lawrence Livermore National Laboratory, Livermore, Calif.; ATK Aerospace Systems, Goleta, Calif., and with support from the Italian Space Agency (ASI) Science Data Center.

    NuSTAR’s mission operations center is at UC Berkeley, with the ASI providing its equatorial ground station located at Malindi, Kenya. The mission’s outreach program is based at Sonoma State University, Rohnert Park, Calif. NASA’s Explorer Program is managed by Goddard. JPL is managed by Caltech for NASA.

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 6:15 pm on February 19, 2015 Permalink | Reply
    Tags: , , , , NASA NuSTAR,   

    From NASA: “NASA, ESA Telescopes Give Shape to Furious Black Hole Winds” 

    NASA

    NASA

    February 19, 2015

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

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

    1
    Supermassive black holes at the cores of galaxies blast out radiation and ultra-fast winds, as illustrated in this artist’s conception. NASA’s NuSTAR and ESA’s XMM-Newton telescopes show that these winds, containing highly ionized atoms, blow in a nearly spherical fashion. Image Credit: NASA/JPL-Caltech

    NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) and ESA’s (European Space Agency) XMM-Newton telescope are showing that fierce winds from a supermassive black hole blow outward in all directions — a phenomenon that had been suspected, but difficult to prove until now.

    2
    NuSTAR

    2
    XMM-Newton

    “We know black holes in the centers of galaxies can feed on matter, and this process can produce winds. This is thought to regulate the growth of the galaxies,” said Fiona Harrison of the California Institute of Technology (Caltech) in Pasadena, California. Harrison is the principal investigator of NuSTAR and a co-author on a new paper about these results appearing in the journal Science. “Knowing the speed, shape and size of the winds, we can now figure out how powerful they are.”

    Supermassive black holes blast matter into their host galaxies, with X-ray-emitting winds traveling at up to one-third the speed of light. In the new study, astronomers determined PDS 456, an extremely bright black hole known as a quasar more than 2 billion light-years away, sustains winds that carry more energy every second than is emitted by more than a trillion suns.

    “Now we know quasar winds significantly contribute to mass loss in a galaxy, driving out its supply of gas, which is fuel for star formation,” said the study’s lead author Emanuele Nardini of Keele University in England.

    NuSTAR and XMM-Newton simultaneously observed PDS 456 on five separate occasions in 2013 and 2014. The space telescopes complement each other by observing different parts of the X-ray light spectrum: XMM-Newton views low-energy and NuSTAR views high-energy.

    Previous XMM-Newton observations had identified black hole winds blowing toward us, but could not determine whether the winds also blew in all directions. XMM-Newton had detected iron atoms, which are carried by the winds along with other matter, only directly in front of the black hole, where they block X-rays. Combining higher-energy X-ray data from NuSTAR with observations from XMM-Newton, scientists were able to find signatures of iron scattered from the sides, proving the winds emanate from the black hole not in a beam, but in a nearly spherical fashion.

    “This is a great example of the synergy between XMM-Newton and NuSTAR,” said Norbert Schartel, XMM-Newton project scientist at ESA. “The complementarity of these two X-ray observatories is enabling us to unveil previously hidden details about the powerful side of the universe.”

    With the shape and extent of the winds known, the researchers could then determine the strength of the winds and the degree to which they can inhibit the formation of new stars.

    Astronomers think supermassive black holes and their home galaxies evolve together and regulate each other’s growth. Evidence for this comes in part from observations of the central bulges of galaxies — the more massive the central bulge, the larger the supermassive black hole.

    This latest report demonstrates a supermassive black hole and its high-speed winds greatly affect the host galaxy. As the black hole bulks up in size, its winds push vast amounts of matter outward through the galaxy, which ultimately stops new stars from forming.

    Because PDS 456 is relatively close, by cosmic standards, it is bright and can be studied in detail. This black hole gives astronomers a unique look into a distant era of our universe, around 10 billion years ago, when supermassive black holes and their raging winds were more common and possibly shaped galaxies as we see them today.

    “For an astronomer, studying PDS 456 is like a paleontologist being given a living dinosaur to study,” said study co-author Daniel Stern of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena. “We are able to investigate the physics of these important systems with a level of detail not possible for those found at more typical distances, during the ‘Age of Quasars.'”

    NuSTAR is a Small Explorer mission led by Caltech and managed by JPL for NASA’s Science Mission Directorate in Washington.

    For more information, visit:

    http://www.nasa.gov/nustar

    and

    http://www.nustar.caltech.edu/

    This discovery has given astronomers their first opportunity to measure the strength of these ultra-fast winds and prove they are powerful enough to inhibit the host galaxy’s ability to make new stars.

    See the full article here.

    Please help promote STEM in your local schools.

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    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

     
  • richardmitnick 8:30 pm on January 8, 2015 Permalink | Reply
    Tags: , , , NASA NuSTAR   

    From JPL: “Will the Real Monster Black Hole Please Stand Up?” 

    JPL

    January 8, 2015
    Whitney Clavin
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-4673
    whitney.clavin@jpl.nasa.gov

    3

    A new high-energy X-ray image from NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, has pinpointed the true monster of a galactic mashup. The image shows two colliding galaxies, collectively called Arp 299, located 134 million light-years away. Each of the galaxies has a supermassive black hole at its heart.

    a
    Arp299

    NASA NuSTAR
    NuSTAR

    [Above first image]NuSTAR has revealed that the black hole located at the right of the pair is actively gorging on gas, while its partner is either dormant or hidden under gas and dust.

    The findings are helping researchers understand how the merging of galaxies can trigger black holes to start feeding, an important step in the evolution of galaxies.

    “When galaxies collide, gas is sloshed around and driven into their respective nuclei, fueling the growth of black holes and the formation of stars,” said Andrew Ptak of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, lead author of a new study accepted for publication in the Astrophysical Journal. “We want to understand the mechanisms that trigger the black holes to turn on and start consuming the gas.”

    NuSTAR is the first telescope capable of pinpointing where high-energy X-rays are coming from in the tangled galaxies of Arp 299. Previous observations from other telescopes, including NASA’s Chandra X-ray Observatory and the European Space Agency’s XMM-Newton, which detect lower-energy X-rays, had indicated the presence of active supermassive black holes in Arp 299. However, it was not clear from those data alone if one or both of the black holes was feeding, or “accreting,” a process in which a black hole bulks up in mass as its gravity drags gas onto it.

    NASA Chandra Telescope
    Chandra

    ESA XMM Newton
    XMM-Newton

    The new X-ray data from NuSTAR — overlaid on a visible-light image from NASA’s Hubble Space Telescope — show that the black hole on the right is, in fact, the hungry one. As it feeds on gas, energetic processes close to the black hole heat electrons and protons to about hundreds of millions of degrees, creating a superhot plasma, or corona, that boosts the visible light up to high-energy X-rays. Meanwhile, the black hole on the left either is “snoozing away,” in what is referred to as a quiescent, or dormant state, or is buried in so much gas and dust that the high-energy X-rays can’t escape.

    NASA Hubble Telescope
    Hubble

    “Odds are low that both black holes are on at the same time in a merging pair of galaxies,” said Ann Hornschemeier, a co-author of the study who presented the results Thursday at the annual American Astronomical Society meeting in Seattle. “When the cores of the galaxies get closer, however, tidal forces slosh the gas and stars around vigorously, and, at that point, both black holes may turn on.”

    NuSTAR is ideally suited to study heavily obscured black holes such as those in Arp 299. High-energy X-rays can penetrate the thick gas, whereas lower-energy X-rays and light get blocked.

    Ptak said, “Before now, we couldn’t pinpoint the real monster in the merger.”

    NuSTAR is a Small Explorer mission led by the California Institute of Technology in Pasadena and managed by NASA’s Jet Propulsion Laboratory, also in Pasadena, for NASA’s Science Mission Directorate in Washington. The spacecraft was built by Orbital Sciences Corporation, Dulles, Va. Its instrument was built by a consortium including Caltech; JPL; the University of California, Berkeley ; Columbia University, New York; NASA’s Goddard Space Flight Center, Greenbelt, Md.; the Danish Technical University in Denmark; Lawrence Livermore National Laboratory, Livermore, Calif.; ATK Aerospace Systems, Goleta, Calif., and with support from the Italian Space Agency (ASI) Science Data Center.

    See the full article here.

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 6:06 pm on January 6, 2015 Permalink | Reply
    Tags: , , , , NASA NuSTAR   

    From LLNL: “NuSTAR Peers Into the Neutron Star Zoo” 


    Lawrence Livermore National Laboratory

    December 2014
    Caryn Meissner

    n

    NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) is the first focusing observatory deployed in orbit for measuring hard x-ray energies between 3 and 80 kiloelectronvolts (keV). NuSTAR contains two focusing telescopes and an array of detectors and is more sensitive than previous technologies for this energy range. The composite background image shows low-energy (soft) x-ray data collected by NASA’s Chandra X-Ray Observatory, infrared data captured by the Spitzer Space Telescope, and pulsar PSR J1640-4631 (blue), which was discovered by NuSTAR and lies in the inner Milky Way galaxy. (Courtesy of NASA, Jet Propulsion Laboratory [JPL], and California Institute of Technology [Caltech].)

    NASA Chandra Telescope
    Chandra

    NASA Spitzer Telescope
    Spitzer

    The deaths of stars are not as final as they seem. These often-violent events give rise to exotic stellar remnants that are dispersed throughout the cosmos. Neutron stars, for example, are created when very massive stars (those with a mass between 10 and 30 times that of our Sun) exhaust their supply of nuclear fuel and die in supernovae explosions. The star generated from such a spectacular event has a radius of about 10 kilometers, mass around 1.5 times that of the Sun, and density of roughly 1017 kilograms per cubic meter (close to the density of a black hole). Neutron stars are thus some of the tiniest, densest celestial objects in the known universe, and they exhibit some of the strongest magnetic fields ever observed. As they are born, they spin rapidly, and this spinning in conjunction with their high magnetic fields produces intermittent pulses of intense radio, x-ray, and gamma-ray emissions.

    More than 40 years after their discovery in the late 1960s, neutron stars continue to intrigue and astonish scientists. “Neutron stars are extreme objects,” says Livermore astrophysicist Julia Vogel, who works in the Physical and Life Sciences Directorate. “Just imagine something with the mass of our Sun squeezed into the San Francisco peninsula spinning at the speed of a household blender.” Although neutron stars were initially believed to belong to a uniform, simple class of stars, research over the last decade has revealed a “zoo” of objects with remarkably diverse properties and behaviors.

    The study of neutron stars has been given a significant boost with the Nuclear Spectroscopic Telescope Array (NuSTAR), a NASA Small Explorer Mission launched in 2012. The technology behind NuSTAR has its roots in Livermore-based research and development. (See S&TR, March 2006, Floating into Thin Air.) With its two x-ray telescopes and advanced semiconductor detectors, NuSTAR achieves sensitivity 100 times greater and resolution 10 times better than previous high-energy satellite observatories.

    In 2013, Vogel began leading a Laboratory Directed Research and Development (LDRD) project that uses NuSTAR to study the hard x-ray emission produced by magnetars—neutron stars with extremely strong magnetic fields. Her team, which includes Laboratory scientist Michael Pivovaroff and astrophysicist Victoria Kaspi from Canada’s McGill University, are using data from NuSTAR to delve further into the energetic nature of neutron stars. NuSTAR’s ability to observe emission at higher angular and energy resolutions will help the researchers better understand how neutron stars produce x rays and whether a star’s properties are determined at birth or are influenced by its environment.

    “Our goal is to develop a ‘grand unification theory’—an overarching theory of neutron star physics and the birth properties of these objects—to explain their incredible diversity,” says Vogel. “NuSTAR observations are helping us understand these ubiquitous and mysterious stellar objects, which will improve our knowledge of stellar evolution, galactic population synthesis, and the study of matter under extreme conditions.”

    m
    Magnetars, such as the one in this artist’s rendering, are thought to be newly formed, isolated stars that have extremely powerful magnetic fields and emit radiation from their magnetic poles. Their irregular bursts of energy affect their rotational period and visibility. (Courtesy of European Southern Observatory.)

    Unpredictable Behavior

    Neutron star types are characterized by the star’s rotational period and the rate at which it slows. By measuring these two properties, scientists can derive the strength of a star’s magnetic field and its age. Most neutron stars were discovered by detecting the radio-frequency signals emitted when kinetic energy is converted into electromagnetic energy (via the stars’ magnetic braking). Because a radio pulsar’s spin axis does not align with its magnetic field, its emissions seem to pulse when viewed from Earth. Radio pulsars are thousands to hundreds of millions of years old, and they exhibit a very large range of magnetic field strengths.

    Magnetars, on the other hand, are the youngest neutron stars and have the most powerful magnetic fields among pulsars, measuring up to a quadrillion (1015) gauss. Magnetars also produce emission observable as periodic pulsation, but they spin more slowly than typical radio pulsars, completing a revolution in 1 to 10 seconds instead of 1 millisecond or less. Interestingly, kinetic energy in spinning magnetars is insufficient for explaining the intensity of their energetic x-ray pulses. “Way more energy comes from magnetars than their kinetic energy alone would allow,” says Pivovaroff, whose expertise is in x-ray optics and astronomy. In addition, the temperamental stars are prone to irregular outbursts of electromagnetic radiation that can affect their rotational period and visibility. “We know their location precisely,” adds Pivovaroff. “Yet sometimes magnetars cannot be detected, and at other times, they are really bright, with intensity increasing by a factor of 10 to several hundreds.”

    The current theory is that magnetars produce x-ray and gamma radiation through the decay of their inner magnetic fields, but the underlying physics and production mechanisms for electromagnetic generation are not well understood. Previous attempts to study magnetar properties in detail were hindered by the limited imaging capabilities of the available hard x-ray observatories. The hard x-ray band is important because it is a transition region from thermal processes to nonthermal ones. NuSTAR is the first focusing hard x-ray observatory deployed in orbit for measuring energies between 3 and 80 kiloelectronvolts (keV). Its two multilayer-coated telescopes image hard x rays onto a sophisticated detector array, which is separated from the optics by a 10-meter mast. The optics, which the Livermore team helped design, build, and calibrate, are key to NuSTAR’s improved resolution.

    During the first year of the LDRD study, the research team created data-analysis tools, including novel algorithms based on existing codes, to interpret the NuSTAR measurements. “Prior to conducting scientific observations, we had the instrument look at well-documented stellar objects as part of our in-orbit calibration efforts,” says Vogel. “We then compared the data to our physics-based computational models, which were designed to predict what we would see in space.”

    The NuSTAR team discovered that ground calibration models could not fully explain the instrument’s in-orbit measurements. This finding was not completely unexpected because simplified models were being used to describe extremely complex phenomena. “The calibration data helped us further improve the models and better understand the discrepancies,” says Vogel. “At Livermore, we were responsible for precision metrology, evaluation, and implementation of results into the ray trace modeling.” Ultimately, the NuSTAR team improved the physics models in the simulations, which reduced the discrepancies between model results and observed data to a level comparable to that achieved for other missions.

    With NuSTAR, researchers can retrieve more detailed images of stellar objects by measuring hard-x-ray emissions. The ROSAT (Röntgen Satellite) Mission, which records emissions between 0.1 and 2.4 keV, captured the left image of supernova remnant CTB109 and magnetar 1E 2259+586 (bright point). The white frame indicates the NuSTAR field of view. (right) Spectroscopic data recorded by NuSTAR in the 3- to 80-keV range provide more details on the magnetar and its environment.

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    With NuSTAR, researchers can retrieve more detailed images of stellar objects by measuring hard-x-ray emissions. The ROSAT (Röntgen Satellite) Mission, which records emissions between 0.1 and 2.4 keV, captured the left image of supernova remnant CTB109 and magnetar 1E 2259+586 (bright point). The white frame indicates the NuSTAR field of view. (right) Spectroscopic data recorded by NuSTAR in the 3- to 80-keV range provide more details on the magnetar and its environment.

    NASA ROSAT staellite
    ROSAT

    A High-Energy Revelation

    In 2014, the research team focused on detecting and analyzing the hard x-ray spectra from several magnetars. “We took an extensive look at one of the most studied magnetars (1E 2259+586), which prior to NuSTAR had been only marginally detected in the hard x-ray energy range,” says Vogel. Spectroscopic techniques determine what energies are emitted by the magnetars and how the spectra differ for the pulsed and constant emission. “We detected hard x-ray pulsations above 20 keV for the first time and studied the magnetar’s spectrum at higher energies than were previously accessible,” she adds. “The hard x-ray data revealed that additional spectral components, which were not required for lower energy (or soft) x-ray measurements alone, were needed to describe the magnetar’s hard and soft x-ray emission together.”

    The team fit the x-ray data obtained from NuSTAR to a recently developed electron–positron outflow model called the Beloborodov model, which could explain the properties and origin of the x-ray emission. “We determined spectral parameters, pulse profile, and pulsed fractions for the NuSTAR data and were able to support the theoretical model,” says Vogel. “Even though current data do not tightly constrain the model parameters, we found that the outflow is likely to originate from a ring on the magnetar rather than from its polar cap, which is surprising.” The team’s findings also support a connection between the spectral turnover and the star’s magnetic fields, consistent with previous observations of other magnetars.

    Using a similar analysis approach, the team characterized a newly discovered magnetar. “We obtained the first timing information of the star, showing that its spin-down rate increased without a glitch,” says Vogel, explaining that a glitch is the sudden spin-up or spin-down that can occur when fluid inside a neutron star rotates faster than the star’s crust. “Because no glitch was observed, the increase is likely to be of magnetospheric origin.”

    The researchers also analyzed spectra from pulsar wind nebulae. These objects form when charged particles are accelerated to relativistic speeds by the neutron star’s rapidly spinning, extremely strong magnetic fields, and they are shocked when constrained by the environment surrounding the star. Observing pulsar wind nebulae will help the team identify the composition of outflowing matter and the relative amount of energy stored in the outflow particle versus the magnetic fields. “Hard x-ray studies enable us to analyze systems where soft x rays are absorbed by interstellar dust,” says Vogel. “The first observations of the Geminga pulsar wind nebula were used for spectroscopy, and the rotation-powered pulsar was detected for the first time in hard x rays above 10 keV.”

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    This composite image of the nebula around pulsar PSR B1509-58 illustrates pulsar wind nebulae. Data were recorded by the Chandra X-Ray Observatory at 0.5 to 2 keV (red) and 2 to 4 keV (green) and by NuSTAR at 7 to 25 keV (blue). NuSTAR’s hard x-ray view reveals the central pulsar. Similar images were obtained for Geminga. (Courtesy of NASA, JPL, Caltech, and McGill University.)

    Resolving Mysteries in X-Ray Astronomy

    “What is being achieved with NuSTAR and Julia’s team is a culmination of more than 10 years of LDRD support,” says Pivovaroff, who worked on the NuSTAR design and helped build the instrument. “Livermore had the long-term commitment and vision to invest in early technology development. Now that it has transitioned into a satellite instrument, we are using the technology to further our understanding of fundamental science.”

    As Vogel and her team continue to advance knowledge of neutron star physics, they look forward to resolving other mysteries in x-ray astronomy. “We can leverage the experience gained from NuSTAR for developing the next generation of x-ray telescopes,” she says. “By being involved in building NuSTAR and its science mission, we can gain a better understanding of what capabilities will be needed for future astrophysics research.” As this research continues, Vogel eagerly anticipates the discoveries to be made during the next year. Only time will tell whether the “animals” in the neutron star zoo share a common connection or if each is a breed of its own.

    See the full article here.

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