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  • richardmitnick 1:47 pm on March 13, 2017 Permalink | Reply
    Tags: , , , , , NASA Chandra, X9   

    From Chandra: “X9 in 47 Tucanae: Star Discovered in Closest Known Orbit Around Likely Black Hole” 

    NASA Chandra Banner
    NASA Chandra Telescope

    NASA Chandra

    March 13, 2017

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    Credit X-ray: NASA/CXC/University of Alberta/A.Bahramian et al.; Illustration: NASA/CXC/M.Weiss
    Release Date March 13, 2017

    The closest orbit between a star and a black hole ever seen has been discovered.

    This extraordinarily close binary is found in 47 Tucanae, a dense cluster of stars on the edge of the Milky Way.

    This binary contains a white dwarf, a low-mass star that has exhausted most or all of its nuclear fuel, and a stellar-mass black hole.

    X-ray data from Chandra provided information about both the presence of the white dwarf and the period of its orbit around the black hole.

    This graphic features an artist’s impression of a star found in the closest orbit known around a black hole, as reported in our latest press release. This discovery was made using data from NASA’s Chandra X-ray Observatory (shown in the inset where low, medium, and high-energy X-rays are colored red, green, and blue respectively), plus NASA’s NuSTAR telescope and the Australia Telescope Compact Array.

    Astronomers found this extraordinarily close stellar pairing in the globular cluster named 47 Tucanae, a dense collection of stars located on the outskirts of the Milky Way galaxy, about 14,800 light years from Earth.

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    NASA

    This particular source, known as X9, has been of interest to scientists for many years. Until a couple of years ago, astronomers thought X9 contained a white dwarf pulling material from a companion star like the Sun. (Astronomers call a pair of objects orbiting one another a ‘binary’ system.) However, a team of scientists in 2015 used radio data to show that X9 likely consisted instead of a black hole pulling gas from a white dwarf companion. These researchers predicted that the white dwarf would take only about 25 minutes to orbit the black hole.

    New Chandra data likely verify this hypothesis and reveal that the X-rays change periodically over about 28 minutes. Additionally, Chandra data show evidence for large amounts of oxygen in the system, a characteristic for the presence of a white dwarf. Therefore, a strong case can be made that that the companion star is a white dwarf, which would then be orbiting the black hole at only about 2.5 times the separation between the Earth and the Moon.

    As seen in the artist’s illustration, the white dwarf is so close to the black hole that much of its material is being pulled away. If it continues to lose mass, this white dwarf may evolve into some exotic sort of planet or completely evaporate.

    In order to make such a close pairing, one possibility is that the black hole smashed into a red giant star, and then gas from the outer regions of the star was ejected from the binary. The remaining core of the red giant would form into a white dwarf, which becomes a binary companion to the black hole. The orbit of the binary would then have shrunk as gravitational waves were emitted, until the black hole started pulling material from the white dwarf. The gravitational waves currently being produced by X9 have a frequency that is too low to be detected with Laser Interferometer Gravitational-Wave Observatory (LIGO). It could potentially be detected with future gravitational wave observatories in space.

    An alternative explanation for the observations is that the binary contains a neutron star, rather than a black hole, that is spinning faster as it pulls material from a white dwarf companion via a disk. This process can lead to the neutron star spinning around its axis thousands of times every second. A few such objects, called transitional millisecond pulsars, have been observed near the end of this spinning up phase. The authors do not favor this possibility as transitional millisecond pulsars have properties not seen in X9, such as extreme variability at X-ray and radio wavelengths. However, they cannot disprove this explanation.

    In addition to Chandra, NASA’s NuSTAR telescope, which observes higher-energy X-rays, and the radio telescope Australia Telescope Compact Array [ATCA] were used to make this discovery.


    NASA/NuSTAR


    CSIRO ATCA at the Paul Wild Observatory, about 25 km west of the town of Narrabri in rural NSW about 500 km north-west of Sydney, AU

    A paper describing these results was recently accepted for publication in the Monthly Notices of the Royal Astronomical Society and is available online. The authors on the paper are Arash Bahramian (University of Alberta), Craig Heinke (Alberta), Vlad Tudor (Curtin University and ICRAR), James Miller-Jones (ICRAR), Slavko Bogdanov (Columbia University), Thomas Maccarone (Texas Tech University), Christian Knigge (University of Southampton), Gregory Sivakoff (Alberta), Laura Chomiuk (Michigan State University), Jay Strader (Michigan State), Javier Garcia (Harvard-Smithsonian Center for Astrophysics), and Timothy Kallman (Goddard Space Flight Center).

    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 8:27 pm on February 6, 2017 Permalink | Reply
    Tags: , NASA Chandra, ,   

    From Chandra: “XJ1500+0154: Black Hole Meal Sets Record for Duration and Size” 

    NASA Chandra Banner

    NASA Chandra Telescope

    NASA Chandra

    February 6, 2017
    Megan Watzke, press release
    Chandra X-ray Center, Cambridge, Mass.
    617-496-7998
    mwatzke@cfa.harvard.edu

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    Illustration
    Credit X-ray: NASA/CXC/UNH/D.Lin et al, Optical: CFHT, Illustration: NASA/CXC/M.Weiss
    Observation Date 23 Feb 2015
    Observation Time 10 hours
    Instrument ACIS

    A supermassive black hole in a small galaxy 1.8 billion light years away has been partaking in a decade-long binge of a star.

    This is known as a tidal disruption event and happens when an object gets too close to a black hole and is torn apart by gravity.

    Other similar events have been seen before but this one is much longer, representing an unusually massive meal.

    A trio of orbiting X-ray telescopes, including Chandra, was used to make this discovery.

    A trio of X-ray observatories has captured a remarkable event in their data: a decade-long binge by a black hole almost two billion light years away. This discovery was made using data from NASA’s Chandra X-ray Observatory, Swift Observatory, and ESA’s XMM-Newton, as reported in our press release.

    NASA/SWIFT Telescope
    NASA/SWIFT Telescope

    This artist’s illustration depicts what astronomers call a “tidal disruption event,” or TDE. This is when an object, such as a star, wanders too close to a black hole and is destroyed by tidal forces generated from the black hole’s intense gravitational forces. During a TDE, some of the stellar debris is flung outward at high speeds, while the rest (shown as the red material in the illustration) becomes hotter as it falls toward the black hole, generating a distinct X-ray flare. A wind blowing away from this infalling material is shown in blue.

    Among observed TDEs, this event involved either the most massive star to be completely ripped apart and devoured by a black hole or the first instance where a smaller star was completely ripped apart. The resulting X-ray source is known as XJ1500+154 and is located in a small galaxy about 1.8 billion light years from Earth. The optical image in the left inset shows this galaxy and a cross to mark the location of XJ1500+0154. This image reveals that XJ1500+0154 is found in the center of the galaxy, implying that the source likely originates from a supermassive black hole that resides there. The image on the right shows XJ1500+0154 in the Chandra image covering the same field.

    The source was not detected in a Chandra observation on April 2, 2005, but was detected in an XMM-Newton observation on July 23, 2005, and reached peak brightness in a Chandra observation on June 5, 2008.

    ESA/XMM Newton
    ESA/XMM Newton

    These observations show that the source became at least 100 times brighter in X-rays. Since then, Chandra, Swift, and XMM-Newton have observed it multiple times.

    The X-ray data also indicate that radiation from material surrounding this black hole has consistently surpassed the so-called Eddington limit, defined by a balance between the outward pressure of radiation from the hot gas and the inward pull of the gravity of the black hole.

    This TDE may help answer the question as to how supermassive black holes in the early universe grow. If supermassive black holes can grow, from TDEs or other means, at rates above those corresponding to the Eddington limit, this could explain how supermassive black holes were able to reach masses about a billion times higher than the sun when the universe was only about a billion years old.

    A paper describing these results appears in the February 6th issue of Nature Astronomy. The authors are Dacheng Lin (University of New Hampshire), James Guillochon (Harvard-Smithsonian Center for Astrophysics), Stefanie Komossa (QianNan Normal University for Nationalities), Enrico Ramirez-Ruiz (University of California, Santa Cruz), Jimmy Irwin (University of Alabama), Peter Maksym (Harvard-Smithsonian), Dirk Grupe (Morehead State University), Olivier Godet (CNRS), Natalie Webb (CNRS), Didier Barret (CNRS), Ashley Zauderer (New York University), Pierre-Alain Duc (CEA-Saclay), Eleazar Carrasco (Gemini Observatory), and Stephen Gwyn (Herzberg Institute of Astrophysics).

    CFHT Telescope, Mauna Kea, Hawaii, USA
    CFHT Interior
    CFHT referenced for optical without comment

    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 12:36 pm on January 19, 2017 Permalink | Reply
    Tags: , , , , Geminga and B0355+54, NASA Chandra,   

    From Chandra: “Geminga and B0355+54: Chandra Images Show That Geometry Solves a Pulsar Puzzle” 

    NASA Chandra Banner

    NASA Chandra Telescope

    NASA Chandra
    [I know a guy, JLT, who just might love to see these images.]
    January 18, 2017

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    Credit X-ray: NASA/CXC/PSU/B.Posselt et al; Infrared: NASA/JPL-Caltech; Illustration: Nahks TrEhnl
    Release Date January 18, 2017

    X-ray images from Chandra have shown distinctly different shapes for the structures around two pulsars.

    Pulsars are rapidly rotating, highly magnetized, neutron stars born in supernova explosions triggered by the collapse of massive stars.

    In certain cases, pulsars generate extensive clouds of high-energy particles called pulsar wind nebulas.

    By studying the shape and orientation of these structures, astronomers may be able to explain the presence or absence of radio and gamma-ray pulses from these systems.

    NASA’s Chandra X-ray Observatory has taken deep exposures of two nearby energetic pulsars flying through the Milky Way galaxy. The shape of their X-ray emission suggests there is a geometrical explanation for puzzling differences in behavior shown by some pulsars.

    Pulsars – rapidly rotating, highly magnetized, neutron stars born in supernova explosions triggered by the collapse of massive stars- were discovered 50 years ago via their pulsed, highly regular, radio emission. Pulsars produce a lighthouse-like beam of radiation that astronomers detect as pulses as the pulsar’s rotation sweeps the beam across the sky.

    Since their discovery, thousands of pulsars have been discovered, many of which produce beams of radio waves and gamma rays. Some pulsars show only radio pulses and others show only gamma-ray pulses. Chandra observations have revealed steady X-ray emission from extensive clouds of high-energy particles, called pulsar wind nebulas, associated with both types of pulsars. New Chandra data on pulsar wind nebulas may explain the presence or absence of radio and gamma-ray pulses.

    This four-panel graphic shows the two pulsars observed by Chandra. Geminga is in the upper left and B0355+54 is in the upper right. In both of these images, Chandra’s X-rays, colored blue and purple, are combined with infrared data from NASA’s Spitzer Space Telescope that shows stars in the field of view.

    NASA/Spitzer Telescope
    NASA/Spitzer Telescope

    Below each data image, an artist’s illustration depicts more details of what astronomers think the structure of each pulsar wind nebula looks like.

    For Geminga, a deep Chandra observation totaling nearly eight days over several years was analyzed to show sweeping, arced trails spanning half a light year and a narrow structure directly behind the pulsar. A five-day Chandra observation of the second pulsar, B0355+54, showed a cap of emission followed by a narrow double trail extending almost five light years.

    The underlying pulsars are quite similar, both rotating about five times per second and both aged about half a million years. However, Geminga shows gamma-ray pulses with no bright radio emission, while B0355+54 is one of the brightest radio pulsars known yet not seen in gamma rays.

    A likely interpretation of the Chandra images is that the long narrow trails to the side of Geminga and the double tail of B0355+54 represent narrow jets emanating from the pulsar’s spin poles. Both pulsars also contain a torus, a disk-shaped region of emission spreading from the pulsar’s spin equator. These donut-shaped structures and jets are crushed and swept back as the pulsars fly through the Galaxy at supersonic speeds.

    In the case of Geminga, the view of the torus is close to edge-on, while the jets point out to the sides. B0355+54 has a similar structure, but with the torus viewed nearly face-on and the jets pointing nearly directly towards and away from Earth. In B0355+54, the swept-back jets appear to lie almost on top of each other, giving a doubled tail.

    Both pulsars have magnetic poles quite close to their spin poles, as is the case for the Earth’s magnetic field. These magnetic poles are the site of pulsar radio emission so astronomers expect the radio beams to point in a similar direction as the jets. By contrast the gamma-ray emission is mainly produced along the spin equator and so aligns with the torus.

    For Geminga, astronomers view the bright gamma-ray pulses along the edge of the torus, but the radio beams near the jets point off to the sides and remain unseen. For B0355+54, a jet points almost along our line of sight towards the pulsar. This means astronomers see the bright radio pulses, while the torus and its associated gamma-ray emission are directed in a perpendicular direction to our line of sight, missing the Earth.

    These two deep Chandra images have, therefore, exposed the spin orientation of these pulsars, helping to explain the presence, and absence, of the radio and gamma-ray pulses.

    The Chandra observations of Geminga and B0355+54 are part of a large campaign, led by Roger Romani of Stanford University, to study six pulsars that have been seen to emit gamma-rays. The survey sample covers a range of ages, spin-down properties and expected inclinations, making it a powerful test of pulsar emission models.

    A paper on Geminga led by Bettina Posselt of Penn State University was accepted for publication in The Astrophysical Journal and is available online. A paper on B0355+54 led by Noel Klingler of the George Washington University was published in the December 20th, 2016 issue of The Astrophysical Journal and is available online.

    See the full article here .

    Please help promote STEM in your local schools.

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    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 8:12 pm on January 6, 2017 Permalink | Reply
    Tags: , , , , Chandra Deep Field South : Deepest X-ray Image Ever Reveals Black Hole Treasure Trove, , NASA Chandra   

    From Chandra- “Chandra Deep Field South : Deepest X-ray Image Ever Reveals Black Hole Treasure Trove” 

    NASA Chandra Banner

    NASA Chandra Telescope

    NASA Chandra

    January 5, 2017

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    Credit X-ray: NASA/CXC/Penn State/B.Luo et al.
    Release Date January 5, 2017
    Luo, B. et al, 2016, ApJS (in press); arXiv:1611.03501; Vito, F. et al, 2016, MNRAS, 463, 348; arXiv:1608.02614

    This image contains the highest concentration of black holes ever seen, equivalent to 5,000 over the area of the full Moon.

    Made with over 7 million seconds of Chandra observing time, this is the deepest X-ray image ever obtained.

    These data give astronomers the best look yet at the growth of black holes over billions of years soon after the Big Bang.

    This is the deepest X-ray image ever obtained, made with over 7 million seconds of observing time with NASA’s Chandra X-ray Observatory. These data give astronomers the best look yet at the growth of black holes over billions of years beginning soon after the Big Bang, as described in our latest press release.

    The image is from the Chandra Deep Field-South, or CDF-S. The full CDF-S field covers an approximately circular region on the sky with an area about two-thirds that of the full Moon. However, the outer regions of the image, where the sensitivity to X-ray emission is lower, are not shown here. The colors in this image represent different levels of X-ray energy detected by Chandra. Here the lowest-energy X-rays are red, the medium band is green, and the highest-energy X-rays observed by Chandra are blue.

    The central region of this image contains the highest concentration of supermassive black holes ever seen, equivalent to about 5,000 objects that would fit into the area of the full Moon and about a billion over the entire sky.

    Researchers used the CDF-S data in combination with data from the Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (CANDELS) and the Great Observatories Origins Deep Survey (GOODS), both including data from NASA’s Hubble Space Telescope to study galaxies and black holes between one and two billion years after the Big Bang.

    CANDELS Cosmic Assembly Near Infrared Deep Extragalactic Legacy Survey
    CANDELS Cosmic Assembly Near Infrared Deep Extragalactic Legacy Survey

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    GOODS

    In one part of the study, the team looked at the X-ray emission from galaxies detected in the Hubble images, at distances between 11.9 and 12.9 billion light years from Earth. About 50 of these distant galaxies were individually detected with Chandra. The team then used a technique called X-ray stacking to investigate X-ray emission from the 2,076 distant galaxies that were not individually detected. They added up all the X-ray counts near the positions of these galaxies, enabling much greater sensitivity to be obtained. Through stacking the team were able to achieve equivalent exposure times up to about 8 billion seconds, equivalent to about 260 years.

    Using these data, the team found evidence that black holes in the early Universe grow mostly in bursts, rather than via the slow accumulation of matter. The team may have also found hints about the types of seeds that form supermassive black holes. If supermassive black holes are born as “light” seeds weighing about 100 times the Sun’s mass, the growth rate required to reach a mass of about a billion times the Sun in the early Universe may be so high that it challenges current models for such growth. If supermassive black holes are born with more mass, the required growth rate is not as high. The data in the CDF-S suggest that the seeds for supermassive black holes may be “heavy” with masses about 10,000 to 100,000 times that of the Sun.

    Such deep X-ray data like those in the CDF-S provide useful insights for understanding the physical properties of the first supermassive black holes. The relative number of luminous and faint objects — in what astronomers call the shape of the “luminosity function” — depends on the mixture of the several physical quantities involved in black hole growth, including the mass of the black hole seeds and the rate at which they are pulling in material. The CDF-S data show a rather “flat” luminosity function (i.e., a relative large number of bright objects) that can be used to infer possible combinations of these physical quantities. However, definitive results can only come from further observations.

    The paper on black hole growth in the early Universe was led by Fabio Vito of Pennsylvania State University in University Park, Penn and was published in an August 10th, 2016 issue of the Monthly Notices of the Royal Astronomical Society. It is available online ( https://arxiv.org/abs/1608.02614 ) The survey paper was led by Bin Luo, also of Penn State and was recently accepted for publication in The Astrophysical Journal Supplement Series. It is also available online ( https://arxiv.org/abs/1611.03501 ).

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

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

     
  • richardmitnick 4:47 pm on December 20, 2016 Permalink | Reply
    Tags: , , Cosmic 'Winter' Wonderland, NASA Chandra, NGC 6357   

    From Chandra: “NGC 6357: Cosmic ‘Winter’ Wonderland” 

    NASA Chandra Banner

    NASA Chandra Telescope

    NASA Chandra

    December 19, 2016

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    Composite
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    X-ray
    3
    Optical
    4
    Infrared
    Credit X-ray: NASA/CXC/PSU/L.Townsley et al; Optical: UKIRT; Infrared: NASA/JPL-Caltech
    Observation Date 7 pointings between July 2004 and July 2016
    References Townsley, L. et al, 2014, ApJS, 213, 1; arXiv:1403.2576

    NGC 6357 is a region where radiation from hot, young stars is energizing the surrounding gas and dust.

    This composite contains X-ray data from Chandra (purple) plus infrared (orange) and optical data (blue).

    X-rays can penetrate the shrouds of gas and dust surrounding infant stars like those in NGC 6357.

    Although there are no seasons in space, this cosmic vista invokes thoughts of a frosty winter landscape. It is, in fact, a region called NGC 6357 where radiation from hot, young stars is energizing the cooler gas in the cloud that surrounds them.

    This composite image contains X-ray data from NASA’s Chandra X-ray Observatory and the ROSAT telescope (purple), infrared data from NASA’s Spitzer Space Telescope (orange), and optical data from the SuperCosmos Sky Survey (blue) made by the United Kingdom Infrared Telescope.

    DLR/NASA ROSAT satellite
    DLR/NASA ROSAT satellite

    NASA/Spitzer Telescope
    NASA/Spitzer Telescope

    UKIRT, located on Mauna Kea, Hawai'i, USA as part of Mauna Kea Observatory
    UKIRT interior
    UKIRT, located on Mauna Kea, Hawaii, USA as part of Mauna Kea Observatory

    Located in our galaxy about 5,500 light years from Earth, NGC 6357 is actually a “cluster of clusters,” containing at least three clusters of young stars, including many hot, massive, luminous stars. The X-rays from Chandra and ROSAT reveal hundreds of point sources, which are the young stars in NGC 6357, as well as diffuse X-ray emission from hot gas. There are bubbles, or cavities, that have been created by radiation and material blowing away from the surfaces of massive stars, plus supernova explosions.

    Astronomers call NGC 6357 and other objects like it “HII” (pronounced “H-two”) regions. An HII region is created when the radiation from hot, young stars strips away the electrons from neutral hydrogen atoms in the surrounding gas to form clouds of ionized hydrogen, which is denoted scientifically as “HII”.

    Researchers use Chandra to study NGC 6357 and similar objects because young stars are bright in X-rays. Also, X-rays can penetrate the shrouds of gas and dust surrounding these infant stars, allowing astronomers to see details of star birth that would be otherwise missed.

    A recent paper on Chandra observations of NGC 6357 by Leisa Townsley of Pennsylvania State University appeared in The Astrophysical Journal Supplement Series and is available online.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

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

     
  • richardmitnick 11:18 am on December 15, 2016 Permalink | Reply
    Tags: , , NASA Chandra, Supernovas & Supernova Remnants, W49B: Smoking Gun Found for Gamma-Ray Burst in Milky Way   

    From Chandra- “W49B: Smoking Gun Found for Gamma-Ray Burst in Milky Way” 

    NASA Chandra Banner
    NASA Chandra Telescope

    NASA Chandra

    June 02, 2004 {From earlier than this blog.]

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    Credit X-ray: NASA/CXC/SSC/J. Keohane et al.; Infrared: Caltech/SSC/J.Rho and T. Jarrett
    Category Supernovas & Supernova Remnants
    Constellation Aquila
    Observation Dates July 08, 2000
    Distance Estimate 26,000 light years

    A composite Chandra X-ray (blue) and Palomar infrared (red and green) image of the supernova remnant W49B reveals a barrel-shaped nebula consisting of bright infrared rings around a glowing bar of intense X-radiation along the axis.

    Caltech Palomar 200 inch Hale Telescope, at Mt Wilson, CA, USA
    Caltech Palomar 200 inch Hale Telescope interior
    Caltech Palomar 200 inch Hale Telescope, at Mt Wilson, CA, USA

    The X-rays in the bar are produced by 15 million degree Celsius gas that is rich in iron and nickel ions. At the ends of the barrel, the X-ray emission flares out to make a hot cap. The X-ray cap is surrounded by a flattened cloud of hydrogen molecules detected in the infrared. These features indicate that jets of hot gas produced in the supernova have encountered a large, dense cloud of gas and dust.

    The following sequence of events has been suggested to account for the X-ray and infrared data: A massive star formed from a dense cloud of dust and gas, shone brightly for a few million years while spinning off rings of gas and pushing them away to form a nearly empty cavity around the star. The star then exhausted its nuclear fuel and its core collapsed to form a black hole. Much of the gas around the black hole was pulled into it, but some, including material rich in iron and nickel was flung away in oppositely directed jets of gas traveling near the speed of light. When the jet hit the dense cloud surrounding the star, it flared out and drove a shock wave into the cloud.

    An observer aligned with one these jets would have seen a gamma-ray burst, a blinding flash in which the concentrated power equals that of ten quadrillion Suns for a minute or so. The view perpendicular to the jets would be a less astonishing, although nonetheless spectacular supernova explosion. For W49B, the jet is tilted out of the plane of the sky by about 20 degrees, but the remains of the jet are visible as a hot X-ray emitting bar of gas.

    W49B is about 35 thousand light years away, whereas the nearest known gamma-ray burst to Earth is several million light years away – most are billions of light years distant. If confirmed, the discovery of a relatively nearby remnant of a gamma-ray burst would give scientists an excellent opportunity to study the aftermath of one of nature’s most violent explosions.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

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

     
  • richardmitnick 3:27 pm on December 8, 2016 Permalink | Reply
    Tags: , , Distant galaxy SPT 0346-52: Under Construction, NASA Chandra   

    From Chandra: “SPT 0346-52: Under Construction: Distant Galaxy Churning Out Stars at Remarkable Rate” 

    NASA Chandra Banner
    NASA Chandra Telescope

    NASA Chandra
    December 8, 2016

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    Credit X-ray: NASA/CXC/Univ of Florida/J.Ma et al; Optical: NASA/STScI; Infrared: NASA/JPL-Caltech; Radio: ESO/NAOJ/NRAO/ALMA; Simulation: Simons Fdn./Moore Fdn./Flatiron Inst./Caltech/C. Hayward & P. Hopkins
    Release Date December 8, 2016

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    Labeled

    SPT0346-52 is a galaxy found about a billion years after the Big Bang that has one of the highest rates of star formation ever seen in a galaxy.

    Astronomers discovered this stellar construction boom by combining data from Chandra and several other telescopes.

    ALMA revealed this galaxy gave off extreme amount of infrared emission, which could have multiple explanations.

    Chandra’s observations ruled out the presence of an actively growing supermassive black hole, bolstering the case of extreme star formation in this galaxy.

    This graphic shows a frame from a computer simulation (main image) and astronomical data (inset) of a distant galaxy undergoing an extraordinary construction boom of star formation, as described in our press release. The galaxy, known as SPT0346-52, is 12.7 billion light years from Earth. This means that astronomers are observing it at a critical stage in the evolution of galaxies, about a billion years after the Big Bang.

    Astronomers were intrigued by SPT0346-52 when data from the Atacama Large Millimeter/submillimeter Array (ALMA) revealed extremely bright infrared emission from this galaxy. This suggested that the galaxy is undergoing a tremendous explosion of star birth.

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

    However, another possible explanation for the excess infrared emission was the presence of a rapidly growing supermassive black hole at the galaxy’s center. In this scenario, gas falling towards the black hole would become much hotter and brighter, causing surrounding dust and gas to glow in infrared light.

    To distinguish between these two possibilities, researchers used NASA’s Chandra X-ray Observatory and CSIRO’s Australia Telescope Compact Array (ATCA), a radio telescope.

    CSIRO ATCA  at the Paul Wild Observatory, about 25 km west of the town of Narrabri in rural NSW about 500 km north-west of Sydney
    CSIRO ATCA at the Paul Wild Observatory, about 25 km west of the town of Narrabri in rural NSW about 500 km north-west of Sydney

    Neither X-rays nor radio waves were detected, so astronomers were able to rule out a growing black hole generating most of the bright infrared light. Therefore, they determined that SPT0346-52 is undergoing a tremendous amount of star formation, an important discovery for a galaxy found so early in the Universe.

    Neither X-rays nor radio waves were detected, so astronomers were able to rule out a growing black hole generating most of the bright infrared light. Therefore, they determined that SPT0346-52 is undergoing a tremendous amount of star formation, an important discovery for a galaxy found so early in the Universe.

    The main panel of the graphic shows one frame of a simulation produced on a supercomputer. The distorted galaxy shown here results from a collision between two galaxies followed by them merging. Astronomers think such a merger could be the reason why SPT0346-52 is having such a boom of stellar construction. Once the two galaxies collide, gas near the center of the merged galaxy (shown as the bright region in the center of the simulation) is compressed, producing the burst of new stars seen forming in SPT0346-52. The dark regions in the simulation represent cosmic dust that absorbs and scatters starlight.

    The inset in this graphic contains a composite image with X-ray data from Chandra (blue), short wavelength infrared data from Hubble (green), infrared light from Spitzer (red) at longer wavelengths, and infrared data from ALMA (magenta) at even longer wavelengths.

    NASA/ESA Hubble Telescope
    NASA/ESA Hubble Telescope

    NASA/Spitzer Telescope
    NASA/Spitzer Telescope

    In the latter case the light from SPT0346-52 is distorted and magnified by the gravity of an intervening galaxy, producing three elongated images in the ALMA data located near the center of the image. SPT0346-52 is not visible in the Hubble or Spitzer data, but the intervening galaxy causing the gravitational lensing is detected. The bright galaxy seen in the Hubble and Spitzer data slightly to the left of the image’s center is unrelated to SPT0346-52.

    There is no blue at the center of the image, showing that Chandra did not detect any X-rays that could have signaled the presence of a growing black hole. The ATCA data, not shown here, also involved the non-detection of a growing black hole. These data suggest that SPT0346-52 is forming at a rate of about 4,500 times the mass of the Sun every year, one of the highest rates seen in a galaxy. This is in contrast to a galaxy like the Milky Way that only forms about one solar mass of new stars per year.

    A paper describing these results, with first author Jingzhe Ma (University of Florida), has been accepted for publication in The Astrophysical Journal and is available online.

    See the full article here .

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

     
  • richardmitnick 11:51 am on November 27, 2016 Permalink | Reply
    Tags: , , CfA Submillimeter Array, Cyg X-3's Little Friend: A Stellar Circle of Life, NASA Chandra, X-ray binaries   

    From Chandra: “Cyg X-3’s Little Friend: A Stellar Circle of Life” 

    NASA Chandra Banner
    NASA Chandra Telescope

    NASA Chandra

    1
    This composite image shows X-rays from NASA’s Chandra X-ray Observatory (white) and radio data from the Smithsonian’s Submillimeter Array (red and blue). The X-ray data reveal a bright X-ray source to the right known as Cygnus X-3, a system containing either a black hole or neutron star (a.k.a. a compact source) left behind after the death of a massive star. Within that bright source, the compact object is pulling material away from a massive companion star. Astronomers call such systems “X-ray binaries.
    Credit X-ray: NASA/CXC/SAO/M.McCollough et al, Radio: ASIAA/SAO/SMA
    Release Date November 21, 2016
    Observation Date 26 Jan 2006
    Observation Time 13 hours 46 min

    CfA Submillimeter Array Mauna Kea, Hawaii, USA
    CfA Submillimeter Array Mauna Kea, Hawaii, USA

    Cygnus X-3 is an X-ray binary where a compact source is pulling material away from a massive companion star.

    Chandra’s high-resolution X-ray vision revealed a cloud of gas and dust that is a separated by a very small distance from Cygnus X-3.

    This gas cloud, dubbed the “Little Friend,” is a Bok globule, the first ever detected in X-rays and the most distant one ever discovered.

    Astronomers detected jets produced by the “Little Friend”, showing that a star is forming inside it.

    A snapshot of the life cycle of stars has been captured where a stellar nursery is reflecting X-rays from a source powered by an object at the endpoint of its evolution. This discovery, described in our latest press release, provides a new way to study how stars form.

    This composite image shows X-rays from NASA’s Chandra X-ray Observatory (white) and radio data from the Smithsonian’s Submillimeter Array (red and blue). The X-ray data reveal a bright X-ray source to the right known as Cygnus X-3, a system containing either a black hole or neutron star (a.k.a. a compact source) left behind after the death of a massive star. Within that bright source, the compact object is pulling material away from a massive companion star. Astronomers call such systems “X-ray binaries.”

    In 2003, astronomers presented results using Chandra’s high-resolution vision in X-rays to identify a mysterious source of X-ray emission located very close to Cygnus X-3 on the sky (smaller white object to the upper left). The separation of these two sources is equivalent to the width of a penny about 800 feet away. A decade later, astronomers reported the new source is a cloud of gas and dust. In astronomical terms, this cloud is rather small – about 0.7 light years in diameter or under the distance between the Sun and Pluto’s orbit.

    Astronomers realized that this nearby cloud was acting as a mirror, reflecting some of the X-rays generated by Cygnus X-3 towards Earth. They nicknamed this object the “Little Friend” due to its close proximity to Cygnus X-3 on the sky and because it also demonstrated the same 4.8-hour variability in X-rays seen in the X-ray binary.

    To determine the nature of the Little Friend, more information was needed. The researchers used the Submillimeter Array (SMA), a series of eight radio dishes atop Mauna Kea in Hawaii, to discover the presence of molecules of carbon monoxide. This is an important clue that helped confirm previous suggestions that the Little Friend is a Bok globule, small, dense, very cold clouds where stars can form. The SMA data also reveal the presence of a jet or outflow within the Little Friend, an indication that a star has started to form inside. The blue portion shows a jet moving towards us and the red portion shows a jet moving away from us.

    These results were published in The Astrophysical Journal Letters, and the paper is also available online. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

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

     
  • richardmitnick 4:12 pm on November 9, 2016 Permalink | Reply
    Tags: , Markarian 1018: Starvation Diet for Black Hole Dims Brilliant Galaxy, NASA Chandra,   

    From Chandra: “Markarian 1018: Starvation Diet for Black Hole Dims Brilliant Galaxy” 

    NASA Chandra Banner

    NASA Chandra Telescope

    NASA Chandra

    November 9, 2016

    1
    Credit X-ray: NASA/CXC/Univ of Sydney/R.McElroy et al, Optical: ESO/CARS Survey
    Release Date November 9, 2016
    Observation Date 27 Nov 2010, 25 Feb 2016

    Markarian 1018 is an “active galaxy” that has brightened and dimmed over about 30 years.

    Such shifting between bright and dim phases has never been studied before in such detail.

    By combining data from Chandra, VLT and several other telescopes, scientists have narrowed in on the explanation.

    It appears the dimming arises from the black hole at the center being deprived of enough fuel to illuminate its surroundings.

    Astronomers may have solved the mystery of the peculiar volatile behavior of a supermassive black hole at the center of a galaxy. Combined data from NASA’s Chandra X-ray Observatory and other observatories suggest that the black hole is no longer being fed enough fuel to make its surroundings shine brightly.

    Many galaxies have an extremely bright core, or nucleus, powered by material falling toward a supermassive black hole. These so-called “active galactic nuclei” or AGN, are some of the brightest objects in the Universe.

    Astronomers classify AGN into two main types based on the properties of the light they emit. One type of AGN tends to be brighter than the other. The brightness is generally thought to depend on either or both of two factors: the AGN could be obscured by surrounding gas and dust, or it could be intrinsically dim because the rate of feeding of the supermassive black hole is low.

    Some AGN have been observed to change once between these two types over the course of only 10 years, a blink of an eye in astronomical terms. However, the AGN associated with the galaxy Markarian 1018 stands out by changing type twice, from a faint to a bright AGN in the 1980s and then changing back to a faint AGN within the last five years. A handful of AGN have been observed to make this full-cycle change, but never before has one been studied in such detail. During the second change in type the Markarian 1018 AGN became eight times fainter in X-rays between 2010 and 2016.

    After discovering the AGN’s fickle nature during a survey project using ESO’s Very Large Telescope (VLT), astronomers requested and received time to observe it with both NASA’s Chandra X-ray Observatory and Hubble Space Telescope.

    ESO/VLT at Cerro Paranal, Chile
    ESO/VLT at Cerro Paranal, Chile

    NASA/ESA Hubble Telescope
    NASA/ESA Hubble Telescope

    The accompanying graphic shows the AGN in optical light from the VLT (left) with a Chandra image of the galaxy’s central region in X-rays showing the point source for the AGN (right).

    Data from ground-based telescopes including the VLT allowed the researchers to rule out a scenario in which the increase in the brightness of the AGN was caused by the black hole disrupting and consuming a single star. The VLT data also cast doubt on the possibility that changes in obscuration by intervening gas cause changes in the brightness of the AGN.

    However, the true mechanism responsible for the AGN’s surprising variation remained a mystery until Chandra and Hubble data was analyzed. Chandra observations in 2010 and 2016 conclusively showed that obscuration by intervening gas was not responsible for the decline in brightness. Instead, models of the optical and ultraviolet light detected by Hubble, NASA’s Galaxy Evolution Explorer (GALEX) and the Sloan Digital Sky Survey in the bright and faint states showed that the AGN had faded because the black hole was being starved of infalling material.

    NASA/Galex telescope
    NASA/Galex telescope

    SDSS Telescope at Apache Point, NM, USA
    SDSS Telescope at Apache Point, NM, USA

    One possible explanation for this starvation is that the inflow of fuel is being disrupted. This disruption could be caused by interactions with a second supermassive black hole in the system. A black hole binary is possible as the galaxy is the product of a collision and merger between two large galaxies, each of which likely contained a supermassive black hole in its center.

    The list observatories used in this finding also include NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) mission and Swift spacecraft.

    NASA/NuSTAR
    NASA/NuSTAR

    NASA/SWIFT Telescope
    NASA/SWIFT Telescope

    This starvation also explains the fading of the AGN in X-rays.

    Two papers, one with the first author of Bernd Husemann (previously at ESO and currently at the Max Planck Institute for Astronomy) and the other with Rebecca McElroy (University of Sydney), describing these results appeared in the September 2016 issue of Astronomy & Astrophysics journal.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

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

     
  • richardmitnick 4:20 pm on October 19, 2016 Permalink | Reply
    Tags: , , NASA Chandra, NGC 5128   

    From Chandra via phys.org: “NGC 5128: Mysterious cosmic objects erupting in X-rays discovered” 

    NASA Chandra Banner

    NASA Chandra Telescope

    NASA Chandra

    1
    Credit NASA/CXC/UA/J.Irwin et al.
    Release Date October 19, 2016

    Two flaring objects in two different galaxies may represent an entirely new phenomenon.

    These objects brighten in X-rays by a factor of 100 in about a minute before returning to previous level in about an hour.

    There are several important differences between these objects and magnetars, which are also known to flare rapidly in X-rays.

    Astronomers used data from both Chandra and XMM-Newton to make this discovery.

    ESA/XMM Newton
    ESA/XMM Newton

    This image shows the location of a remarkable source that dramatically flares in X-rays unlike any ever seen. Along with another similar source found in a different galaxy, these objects may represent an entirely new phenomenon, as reported in our latest press release.

    These two objects were both found in elliptical galaxies, NGC 5128 (also known as Centaurus A) shown here and NGC 4636. In this Chandra X-ray Observatory image of NGC 5128, low, medium, and high-energy X-rays are colored red, green, and blue, and the location of the flaring source is outlined in the box to the lower left.

    Both of these mysterious sources flare dramatically – becoming a hundred times brighter in X-rays in about a minute before steadily returning to their original X-ray levels about an hour later. At their X-ray peak, these objects qualify as ultraluminous X-ray sources (ULXs) that give off hundreds to thousands of times more X-rays than typical X-ray binary systems where a star is orbiting a black hole or neutron star.

    Five flares were detected from the source located near NGC 5128, which is at a distance of about 12 million light years from Earth. A movie showing the average change in X-rays for the three flares with the most complete Chandra data, covering both the rise and fall, is shown in the inset.

    The source associated with the elliptical galaxy NGC 4636, which is located about 47 million light years away, was observed to flare once.

    The only other objects known to have such rapid, bright, repeated flares involve young neutron stars such as magnetars, which have extremely powerful magnetic fields. However, these newly flaring sources are found in populations of much older stars. Unlike magnetars, the new flaring sources are likely located in dense stellar environments, one in a globular cluster and the other in a small, compact galaxy.

    When they are not flaring, these newly discovered sources appear to be normal binary systems where a black hole or neutron star is pulling material from a companion star similar to the Sun. This indicates that the flares do not significantly disrupt the binary system.

    While the nature of these flares is unknown, the team has begun to search for answers. One idea is that the flares represent episodes when matter pulled away from a companion star falls rapidly onto a black hole or neutron star. This could happen when the companion makes its closest approach to the compact object in an eccentric orbit. Another explanation could involve matter falling onto an intermediate-mass black hole, with a mass of about 800 times that of the Sun for one source and 80 times that of the Sun for the other.

    This result is describing in a paper appearing in the journal Nature on October 20, 2016. The authors are Jimmy Irwin (University of Alabama), Peter Maksym (Harvard-Smithsonian Center for Astrophysics), Gregory Sivakoff (University of Alberta), Aaron Romanowsky (San Jose State University), Dacheng Lin (University of New Hampshire), Tyler Speegle, Ian Prado, David Mildebrath (University of Alabama), Jay Strader (Michigan State University), Jifeng Lui (Chinese Academy of Sciences), and Jon Miller (University of Michigan).

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

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

     
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