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  • richardmitnick 4:45 am on February 26, 2015 Permalink | Reply
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    From Chandra- “NGC 2276: NASA’s Chandra Finds Intriguing Member of Black Hole Family Tree “ 

    NASA Chandra

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    Credit X-ray: NASA/CXC/SAO/M.Mezcua et al & NASA/CXC/INAF/A.Wolter et al; Optical: NASA/STScI and DSS; Inset: Radio: EVN/VLBI
    Release Date February 25, 2015

    An intriguing object has been found in one of the spiral arms of the galaxy NGC 2276. This source, called NGC 2276-3c, appears to be an intermediate-mass black hole. According to X-ray and radio data, NGC 2276-3c contains about 50,000 times the mass of the Sun.

    A newly discovered object in the galaxy NGC 2276 may prove to be an important black hole that helps fill in the evolutionary story of these exotic objects, as described in our latest press release. The main image in this graphic contains a composite image of NGC 2766 that includes X-rays from NASA’s Chandra X-ray Observatory (pink) combined with optical data from the Hubble Space Telescope and the Digitized Sky Survey (red, green and blue). The inset is a zoom into the interesting source that lies in one of the galaxy’s spiral arms. This object, called NGC 2276-3c, is seen in radio waves (red) in observations from the European Very Long Baseline Interferometry Network, or EVN.

    NASA Hubble Telescope
    Hubble

    European VLBI
    European VLBI

    Astronomers have combined the X-ray and radio data to determine that NGC 2766-3c is likely an intermediate-mass black hole (IMBH). As the name suggests, IMBHs are black holes that are larger than stellar mass black holes that contain about five to thirty times the mass of the Sun, but smaller than supermassive black holes that are millions or even billions of solar masses. The researchers estimated the mass of NGC 2766-3c using a well-known relationship between how bright the source is in radio and X-rays, and the mass of the black hole. The X-ray and radio brightness were based on observations with Chandra and the EVN. They found that NGC 2276-3c contains about 50,000 times the mass of the Sun.

    IMBHs are interesting to astronomers because they may be the seeds that eventually evolve into supermassive black holes. They also may be strongly influencing their environment. This latest result on NGC 2276-3c suggests that it may be suppressing the formation of new stars around it. The EVN radio data reveal an inner jet that extends about 6 light years from NGC 2276-3c. Additional observations by the NSF’s Karl Jansky Very Large Array (VLA) show large-scale radio emission extending out to over 2,000 light years away from the source.

    NRAO VLA
    NRAO/VLA

    A region along the jet extending to about 1,000 light years away from NGC 2766-3c is devoid of young stars. This might provide evidence that the jet has cleared out a cavity in the gas, preventing new stars from forming there. The VLA data also reveal a large population of stars at the edge of the radio emission from the jet. This enhanced star formation could take place either when the material swept out by the jet collides with dust and gas in between the stars in NGC 2276, or when triggered by the merger of NGC 2276 with a dwarf galaxy.

    In a separate study, Chandra observations of this galaxy have also been used to examine its rich population of ultraluminous X-ray sources (ULXs). Sixteen X-ray sources are found in the deep Chandra dataset seen in this composite image, and eight of these are ULXs including NGC 2276-3c. Chandra observations show that one apparent ULX observed by ESA’s XMM-Newton is actually five separate ULXs, including NGC 2276-3c.

    ESA XMM Newton
    ESA/XMM-Newton

    This ULX study shows that about five to fifteen solar masses worth of stars are forming each year in NGC 2276. This high rate of star formation may have been triggered by a collision with a dwarf galaxy, supporting the merger idea for the IMBH’s origin.

    The study on NGC 2276-3c was conducted by Mar Mezcua (previously in the Instituto de Astrofisica de Canarias and now at the Harvard-Smithsonian Center for Astrophysics), Tim Roberts (University of Durham, UK), Andrei Lobanov ( Max Planck Institute for Radio Astronomy, Germany), and Andrew Sutton (University of Durham) and will appear in the Monthly Notices of the Royal Astronomical Society (MNRAS). A separate paper on the ULX population in NGC 2276 will also appear in MNRAS and the authors on that study are Anna Wolter (National Institute for Astrophysics (INAF) in Milan, Italy), Paolo Esposito (INAF), Michela Mapelli (INAF, Padova), Fabio Pizzolato (University of Milan, Italy), and Emanuele Ripamonti (University of Padova, Italy).

    See the full article here.

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

     
  • richardmitnick 4:32 pm on February 12, 2015 Permalink | Reply
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    From Chandra: “G299.2-2.9: Exploded Star Blooms Like a Cosmic Flower” 

    NASA Chandra

    February 12, 2015

    Chandra observations of the supernova remnant G299.2-2.9 reveal important information about this object.The shape of the supernova remnant today gives clues about the explosion that created it about 4,500 years ago. G299.2-2.9 belongs to the class of supernovas known as type 1as. Astronomers are trying to determine the exact mechanisms that produce these particular explosions.

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    Composite

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    X-ray

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    Infrared
    Credit X-ray: NASA/CXC/U.Texas/S.Post et al, Infrared: 2MASS/UMass/IPAC-Caltech/NASA/NSF

    Because the debris fields of exploded stars, known as supernova remnants, are very hot, energetic, and glow brightly in X-ray light, NASA’s Chandra X-ray Observatory has proven to be a valuable tool in studying them. The supernova remnant called G299.2-2.9 (or G299 for short) is located within our Milky Way galaxy, but Chandra’s new image of it is reminiscent of a beautiful flower here on Earth.

    G299 was left over by a particular class of supernovas called Type Ia. Astronomers think that a Type Ia supernova is a thermonuclear explosion – involving the fusion of elements and release of vast amounts of energy – of a white dwarf star in a tight orbit with a companion star. If the white dwarf’s partner is a typical, Sun-like star, the white dwarf can become unstable and explode as it draws material from its companion. Alternatively, the white dwarf is in orbit with another white dwarf, the two may merge and can trigger an explosion.

    Regardless of their triggering mechanism, Type Ia supernovas have long been known to be uniform in their extreme brightness, usually outshining the entire galaxy where they are found. This is important because scientists use these objects as cosmic mileposts [“standard candles“], allowing them to accurately measure the distances of galaxies billions of light years away, and to determine the rate of expansion of the Universe.

    Traditional theoretical models of Type Ia supernovas generally predict that these explosions would be symmetric, creating a near perfect sphere as they expand. These models have been supported by results showing that remnants of Type Ia supernovas are more symmetric than remnants of supernovas involving the collapse of massive stars.

    However, astronomers are discovering that some Type Ia supernova explosions may not be as symmetric as previously thought. G299 could be an example of such an “unusual” Type Ia supernova. Using a long observation from Chandra, researchers discovered the shell of debris from the exploded star is expanding differently in various directions.

    In this new Chandra image, red, green, and blue represent low, medium, and high-energy X-rays, respectively, detected by the telescope. The medium energy X-rays include emission from iron and the hard-energy X-rays include emission from silicon and sulfur. The X-ray data have been combined with infrared data from ground-based 2MASS survey that shows the stars in the field of view.

    By performing a detailed analysis of the X-rays, researchers found several clear examples of asymmetry in G299. For example, the ratio between the amounts of iron and silicon in the part of the remnant just above the center is larger than in the part of the remnant just below the center. This difference can be seen in the greener color of the upper region compared to the bluer color of the lower region. Also, there is a strongly elongated portion of the remnant extending to the right. In this region, the relative amount of iron to silicon is similar to that found in the southern region of the remnant.

    The patterns seen in the Chandra data suggest that a very lopsided explosion may have produced this Type Ia supernova. It might also be that the remnant has been expanding into an environment where the medium it encountered was uneven. Regardless of the ultimate explanation, observations of G299 and others like it are showing astronomers just how varied such beautiful cosmic flowers can be.

    A paper describing these results was published in the September 1st, 2014 issue of The Astrophysical Journal, and is available online. The authors are Seth Post and Sangwook Park from the University of Texas at Arlington in Texas; Carles Badenes from the University of Pittsburgh, in Pittsburgh, Pennsylvania; David Burrows from Pennsylvania State University in University Park, Pennsylvania; John Hughes from Rutgers University in Piscataway, New Jersey; Jae-Joon Lee from the Korea Astronomy and Space Science Institute; Koji Mori from the University of Miyazaki in Japan and Patrick Slane from the Harvard-Smithsonian Center of Astrophysics in Cambridge, Massachusetts.

    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 5:49 pm on January 26, 2015 Permalink | Reply
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    From Chandra: “IYL 2015: Chandra Celebrates The International Year of Light” 

    NASA Chandra

    New images are being released to celebrate the International Year of Light 2015. Each image contains X-rays from Chandra, along with data in other types of light from various telescopes.
    These images illustrate how astronomers use different types of light together to get a more complete view of objects in space.

    The year of 2015 has been declared the International Year of Light (IYL) by the United Nations. Organizations, institutions, and individuals involved in the science and applications of light will be joining together for this yearlong celebration to help spread the word about the wonders of light.

    In many ways, astronomy uses the science of light. By building telescopes that can detect light in its many forms, from radio waves on one end of the “electromagnetic spectrum” to gamma rays on the other, scientists can get a better understanding of the processes at work in the Universe.

    NASA’s Chandra X-ray Observatory explores the Universe in X-rays, a high-energy form of light. By studying X-ray data and comparing them with observations in other types of light, scientists can develop a better understanding of objects likes stars and galaxies that generate temperatures of millions of degrees and produce X-rays.

    To recognize the start of IYL, the Chandra X-ray Center is releasing a set of images that combine data from telescopes tuned to different wavelengths of light. From a distant galaxy to the relatively nearby debris field of an exploded star, these images demonstrate the myriad ways that information about the Universe is communicated to us through light.

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    SNR E0519-69.0:
    When a massive star exploded in the Large Magellanic Cloud, a satellite galaxy to the Milky Way, it left behind an expanding shell of debris called SNR 0519-69.0. Here, multimillion degree gas is seen in X-rays from Chandra (blue). The outer edge of the explosion (red) and stars in the field of view are seen in visible light from Hubble.

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    Messier 51 (M51):
    This galaxy, nicknamed the “Whirlpool,” is a spiral galaxy, like our Milky Way, located about 30 million light years from Earth. This composite image combines data collected at X-ray wavelengths by Chandra (purple), ultraviolet by the Galaxy Evolution Explorer (GALEX, blue); visible light by Hubble (green), and infrared by Spitzer (red).

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    MSH 11-62:
    When X-rays, shown in blue, from Chandra and XMM-Newton are joined in this image with radio data from the Australia Telescope Compact Array (pink) and visible light data from the [Sloan] Digitized Sky Survey ([S]DSS, yellow), a new view of the region emerges. This object, known as MSH 11-62, contains an inner nebula of charged particles that could be an outflow from the dense spinning core left behind when a massive star exploded.

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    Cygnus A:
    This galaxy, at a distance of some 700 million light years, contains a giant bubble filled with hot, X-ray emitting gas detected by Chandra (blue). Radio data from the NSF’s Very Large Array (red) reveal “hot spots” about 300,000 light years out from the center of the galaxy where powerful jets emanating from the galaxy’s supermassive black hole end. Visible light data (yellow) from both Hubble and the DSS complete this view.

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    RCW 86:
    This supernova remnant is the remains of an exploded star that may have been witnessed by Chinese astronomers almost 2,000 years ago. Modern telescopes have the advantage of observing this object in light that is completely invisible to the unaided human eye. This image combines X-rays from Chandra (pink and blue) along with visible emission from hydrogen atoms in the rim of the remnant, observed with the 0.9-m Curtis Schmidt telescope at the Cerro Tololo Inter-American Observatory (yellow).

    Credit X-ray: NASA/CXC/SAO; UV: NASA/JPL-Caltech; Optical: NASA/STScI; IR: NASA/JPL-Caltech
    Release Date January 22, 2015

    NASA Hubble Telescope
    Hubble

    NASA Galex telescope
    GALEX

    NASA Spitzer Telescope
    Spitzer

    ESA XMM Newton
    ESA/XMM-Newton

    Australian Telescope Compact Array
    Australia Compact Telescope Array

    Sloan Digital Sky Survey Telescope
    SDSS Telescope

    NRAO VLA
    NRAO VLA

    NOAO Curtis Schmidt Telescope Exterior
    NOAO Curtis Schmidt Telescope

    See the full article here.

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

     
  • richardmitnick 9:58 pm on January 5, 2015 Permalink | Reply
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    From Chandra: “NASA’s Chandra Detects Record-Breaking Outburst from Milky Way’s Black Hole” 

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    ESOcast

    Astronomers have observed the largest X-ray flare ever detected from the supermassive black hole at the center of the Milky Way galaxy. This event, detected by NASA’s Chandra X-ray Observatory, raises questions about the behavior of this giant black hole and its surrounding environment. The supermassive black hole at the center of our galaxy, called Sagittarius A*, or Sgr A*, is estimated to contain about 4.5 million times the mass of our sun. Astronomers made the unexpected discovery while using Chandra to observe how Sgr A* would react to a nearby cloud of gas known as G2.

    “Unfortunately, the G2 gas cloud didn’t produce the fireworks we were hoping for when it got close to Sgr A*,” said lead researcher Daryl Haggard of Amherst College in Massachusetts. “However, nature often surprises us and we saw something else that was really exciting.”

    On Sept. 14, 2013, Haggard and her team detected an X-ray flare from Sgr A* 400 times brighter than its usual, quiet state. This “megaflare” was nearly three times brighter than the previous brightest X-ray flare from Sgr A* in early 2012. After Sgr A* settled down, Chandra observed another enormous X-ray flare 200 times brighter than usual on Oct. 20, 2014.
    Astronomers estimate that G2 was closest to the black hole in the spring of 2014, 15 billion miles away. The Chandra flare observed in September 2013 was about a hundred times closer to the black hole, making the event unlikely related to G2.

    The researchers have two main theories about what caused Sgr A* to erupt in this extreme way. The first is that an asteroid came too close to the supermassive black hole and was torn apart by gravity. The debris from such a tidal disruption became very hot and produced X-rays before disappearing forever across the black hole’s point of no return, or event horizon. “If an asteroid was torn apart, it would go around the black hole for a couple of hours – like water circling an open drain – before falling in,” said co-author Fred Baganoff of the Massachusetts Institute of Technology in Cambridge, Massachusetts. “That’s just how long we saw the brightest X-ray flare last, so that is an intriguing clue for us to consider.” If this theory holds up, it means astronomers may have found evidence for the largest asteroid to produce an observed X-ray flare after being torn apart by Sgr A*.

    A second theory is that the magnetic field lines within the gas flowing towards Sgr A* could be tightly packed and become tangled. These field lines may occasionally reconfigure themselves and produce a bright outburst of X-rays. These types of magnetic flares are seen on the sun, and the Sgr A* flares have similar patterns of intensity. “The bottom line is the jury is still out on what’s causing these giant flares from Sgr A*,” said co-author Gabriele Ponti of the Max Planck Institute for Astrophysics in Garching, Germany. “Such rare and extreme events give us a unique chance to use a mere trickle of infalling matter to understand the physics of one of the most bizarre objects in our galaxy.”

    In addition to the giant flares, the G2 observing campaign with Chandra also collected more data on a magnetar: a neutron star with a strong magnetic field, located close to Sgr A*. This magnetar is undergoing a long X-ray outburst, and the Chandra data are allowing astronomers to better understand this unusual object.

    These results were presented at the 225th meeting of the American Astronomical Society being held in Seattle.

    This article is from email received today from hqnews@newsletters.nasa.gov. If you want the latest and greatest, sign up for NASA newsletters.

    Another Chandra image of Sgr A*

    sgr

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

     
  • richardmitnick 3:51 pm on December 27, 2014 Permalink | Reply
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    From Chandra: “Perseus A: A Monster Galaxy at the Heart of Perseus Cluster” 2008 

    NASA Chandra

    August 20, 2008

    The active galaxy NGC 1275 is also a well-known radio source (Perseus A) and a strong emitter of X-rays due to the presence of a black hole in the center of the galaxy. The behemoth also lies at the center of the cluster of galaxies known as the Perseus Cluster. By combining multi-wavelength images into a single composite, the dynamics of the galaxy are more easily visible. Detail and structure from x-ray, optical and radio wavelengths combine for an aesthetically pleasing, but nonetheless violent depiction of events going on at the heart of the galaxy.

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    NGC 1275 (Perseus A)
    Credit X-ray: NASA/CXC/IoA/A.Fabian et al.; Radio: NRAO/VLA/G. Taylor; Optical: NASA/ESA/Hubble Heritage (STScI/AURA) & Univ. of Cambridge/IoA/A. Fabian
    Release Date August 20, 2008
    Observation Date August 08 & 10, 2002

    pc
    An accumulation of 270 hours of Chandra observations of the central regions of the Perseus galaxy cluster reveals evidence of the turmoil that has wracked the cluster for hundreds of millions of years. One of the most massive objects in the universe, the cluster contains thousands of galaxies immersed in a vast cloud of multimillion degree gas with the mass equivalent of trillions of suns. Enormous bright loops, ripples, and jet-like streaks are apparent in the image. The dark blue filaments in the center are likely due to a galaxy that has been torn apart and is falling into NGC 1275, a.k.a. Perseus A, the giant galaxy that lies at the center of the cluster.

    Chandra data from the Advanced CCD Imaging Spectrometer (ACIS) covers X-ray energies from 0.3-7keV. Hubble data from the Advanced Camera for Surveys covers optical wavelengths in the red, green and blue. Radio data from NRAO’s Very Large Array at 328 MHz was also used. In the composite image, the X-ray data contribute to the soft violet shells around the outside of the center. The pinkish lobes toward the center of the galaxy are from radio frequencies. The radio emission, tracing jets from the black hole, fills the X-ray cavities. Dust lanes, star-forming regions, hydrogen filaments, foreground stars, and background galaxies are contributions from the Hubble optical data.

    NASA Chandra ACIS
    NASA/Chandra ACIS

    NASA Hubble Telescope
    NASA Hubble schematic
    NASA/ESA Hubble

    NASA Hubble ACS
    Hubble ACS

    NRAO VLA
    NRAO VLA

    See the full article here.

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

     
  • richardmitnick 4:45 pm on December 18, 2014 Permalink | Reply
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    From Chandra: “Chandra Weighs Most Massive Galaxy Cluster in Distant Universe” 

    NASA Chandra

    The most distant massive galaxy cluster, located about 9.6 billion light years from Earth, has been found and studied. Astronomers nicknamed this object the “Gioello” (Italian for “Jewel”) Cluster.
    Using Chandra data, researchers were able to accurately determine the mass and other properties of this cluster. Results like this help astronomers understand how galaxy clusters have evolved over time.

    copm
    Composite

    xray
    X-Ray

    infra
    Infrared

    opt
    Optical
    Credit X-ray: NASA/CXC/INAF/P.Tozzi, et al; Optical: NAOJ/Subaru and ESO/VLT; Infrared: ESA/Herschel
    Release Date December 18, 2014

    A newly discovered galaxy cluster is the most massive one ever detected with an age of 800 million years or younger. Using data from NASA’s Chandra X-ray Observatory, astronomers have accurately determined the mass and other properties of this cluster, as described in our latest press release. This is an important step in understanding how galaxy clusters, the largest structures in the Universe held together by gravity, have evolved over time.

    A composite image shows the distant and massive galaxy cluster that is officially known as XDCP J0044.0-2033. Researchers, however, have nicknamed it “Gioiello”, which is Italian for “jewel”. They chose this name because an image of the cluster contains many sparkling colors from the hot, X-ray emitting gas and various star-forming galaxies within the cluster. Also, the research team met to discuss the Chandra data for the first time at Villa il Gioiello, a 15th century villa near the Observatory of Arcetri, which was the last residence of prominent Italian astronomer Galileo Galilei. In this new image of the Gioiello Cluster, X-rays from Chandra are purple, infrared data from ESA’s Hershel Space Telescope appear as large red halos around some galaxies, and optical data from the Subaru telescope on Mauna Kea in Hawaii are red, green, and blue.

    ESA Herschel
    ESA Herschel schematic
    ESA/Herschel

    NAOJ Subaru Telescope
    NAOJ Subaru Telescope interior

    Astronomers first detected the Gioiello Cluster, located about 9.6 billion light years away, using ESA’s XMM-Newton observatory. They were then approved to study the cluster with Chandra in observations that were equivalent to over four days of time. This is the deepest X-ray observation yet made on a cluster beyond a distance of about 8 billion light years.

    ESA XMM Newton
    ESA XMM-Newton schematc
    ESA/XMM-Newton

    The long observing time allowed the researchers to gather enough X-ray data from Chandra that, when combined with scientific models, provides an accurate weight of the cluster. They determined that the Gioiello Cluster contains a whopping 400 trillion times the mass of the Sun.

    Previously, astronomers had found an enormous galaxy cluster, known as “El Gordo,” at a distance of 7 billion light years away and a few other large, distant clusters. According to the best current model for how the Universe evolved, there is a low chance of finding clusters as massive as the Gioiello Cluster and El Gordo. The new findings suggest that there might be problems with the theory, and are enticing astronomers to look for other distant and massive clusters.

    e
    El Gordo consists of two separate galaxy subclusters colliding at several million
    kilometres per hour.

    These results are being published in The Astrophysical Journal available online. The first author is Paolo Tozzi, from the National Institute for Astrophysics (INAF) in Florence, Italy. The co-authors are Johana Santos, also from INAF in Florence, Italy; James Jee from the University of California in Davis; Rene Fassbender from INAD in Rome, Italy; Piero Rosati from the University of Ferrara in Ferrara, Italy; Alessandro Nastasi from the University of Paris-Sud, in Orsay, France; William Forman from Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, MA; Barbara Sartoris and Stefano Borgani from the University of Trieste in Trieste, Italy; Hans Boehringer from the Max Planck Institute for Astrophysics in Garching, Germany; Bruno Altieri from the European Space Agency in Madrid, Spain; Gabriel Pratt from CEA Saclay in Cedex, France; Mario Nonino from the University of Trieste in Trieste, Italy and Christine Jones from CfA.

    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 10:05 pm on December 11, 2014 Permalink | Reply
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    From Chandra: “NGC 2207 and IC 2163: Galactic Get-Together has Impressive Light Display” 

    NASA Chandra

    December 11, 2014

    NGC 2207 and IC 2163 are two spiral galaxies in the process of merging. This pair contains a large collection of super bright X-ray objects called “ultraluminous X-ray sources” (ULXs). Astronomers have found evidence for three supernova explosions within this pair in the past 15 years. A new composite image of the system contains X-rays from Chandra (pink) along with optical and infrared data.

    comp
    Composite

    xray
    X-Ray

    infr
    Infrared

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    Optical

    Credit X-ray: NASA/CXC/SAO/S.Mineo et al, Optical:
    NASA/STScI, Infrared: NASA/JPL-Caltech
    Release Date December 11, 2014

    At this time of year, there are lots of gatherings often decorated with festive lights. When galaxies get together, there is the chance of a spectacular light show as is the case with NGC 2207 and IC 2163

    Located about 130 million light years from Earth, in the constellation of Canis Major, this pair of spiral galaxies has been caught in a grazing encounter. NGC 2207 and IC 2163 have hosted three supernova explosions in the past 15 years and have produced one of the most bountiful collections of super bright X-ray lights known. These special objects – known as “ultraluminous X-ray sources” (ULXs) – have been found using data from NASA’s Chandra X-ray Observatory.

    As in our Milky Way galaxy, NGC 2207 and IC 2163 are sprinkled with many star systems known as X-ray binaries, which consist of a star in a tight orbit around either a neutron star or a “stellar-mass” black hole. The strong gravity of the neutron star or black hole pulls matter from the companion star. As this matter falls toward the neutron star or black hole, it is heated to millions of degrees and generates X-rays.

    ULXs have far brighter X-rays than most “normal” X-ray binaries. The true nature of ULXs is still debated, but they are likely a peculiar type of X-ray binary. The black holes in some ULXs may be heavier than stellar mass black holes and could represent a hypothesized, but as yet unconfirmed, intermediate-mass category of black holes.

    This composite image of NGC 2207 and IC 2163 contains Chandra data in pink, optical light data from the Hubble Space Telescope in red, green, and blue (appearing as blue, white, orange, and brown), and infrared data from the Spitzer Space Telescope in red.

    NASA Hubble Telescope
    NASA/ESA Hubble

    NASA Spitzer Telescope
    NASA/Spitzer

    The new Chandra image contains about five times more observing time than previous efforts to study ULXs in this galaxy pair. Scientists now tally a total of 28 ULXs between NGC 2207 and IC 2163. Twelve of these vary over a span of several years, including seven that were not detected before because they were in a “quiet” phase during earlier observations.

    The scientists involved in studying this system note that there is a strong correlation between the number of X-ray sources in different regions of the galaxies and the rate at which stars are forming in these regions. The composite image shows this correlation through X-ray sources concentrated in the spiral arms of the galaxies, where large amounts of stars are known to be forming. This correlation also suggests that the companion star in the binary systems is young and massive.

    Colliding galaxies like this pair are well known to contain intense star formation. Shock waves – like the sonic booms from supersonic aircraft – form during the collision, leading to the collapse of clouds of gas and the formation of star clusters. In fact, researchers estimate that the stars associated with the ULXs are very young and may only be about 10 million years old. In contrast, our Sun is about halfway through its 10-billion-year lifetime. Moreover, analysis shows that stars of various masses are forming in this galaxy pair at a rate equivalent to form 24 stars the mass of our sun per year. In comparison, a galaxy like our Milky Way is expected to spawn new stars at a rate equivalent to only about one to three new suns every year.

    A paper describing these results has been accepted for publication in The Astrophysical Journal and is available online. The authors of the paper are Stefano Mineo of the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA; Saul Rappaport from the Massachusetts Institute of Technology (MIT) in Cambridge, MA; Alan Levine from MIT; David Pooley from Sam Houston State University in Huntsville, TX; Benjamin Steinhorn from Harvard Medical School in Boston, MA, and Jeroen Homan from MIT.

    See the full article here.

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

     
  • richardmitnick 4:00 pm on November 18, 2014 Permalink | Reply
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    From LLNL: “Black hole loses its appetite for gassy cloud” 


    Lawrence Livermore National Laboratory

    Nov. 18, 2014

    Anne M Stark
    stark8@llnl.gov
    925-422-9799

    In a showdown of black hole versus G2 – a cloud of gas and dust – it looks like G2 won.

    g2
    This simulation shows the possible behavior of a gas cloud (G2) that has been observed approaching the black hole at the center of the Milky Way. Graphic by ESO/MPE/Marc Schartmann.

    Recent research shows that G2 came within 30 billion kilometers of the super-massive black hole at the center of our galaxy, yet managed to escape from the gravitational pull of the black hole.

    Initially, a supercomputer simulation prepared by two Lab physicists and a former postdoc more than two years ago suggested that some of G2 would survive, although its surviving mass would be torn apart, leaving it with a different shape and questionable fate.

    The findings are the work of computational physicist Peter Anninos and astrophysicist Stephen Murray, both of AX division within the Weapons and Complex Integration Directorate (WCI), along with their former postdoc Chris Fragile, now an associate professor at the College of Charleston in South Carolina, and his student, Julia Wilson.

    The team’s simulations allowed the members to more efficiently follow the cloud’s progression toward the black hole.

    But recent observations by an outside group show that G2 managed to escape the appetite of the black hole.

    “For it to have survived means that some gravity is keeping it intact,” Murray said. “The mass of the gas cloud by itself is far too small to hold the cloud together. If there were nothing else there, the cloud would have been torn apart, as indicated by our models and those of other researchers.”

    The black hole is known as Sagittarius A-star (Sgr A*). “Sgr” is the abbreviation for Sagittarius, the constellation in the direction of the center of the Milky Way. Most galaxies have a black hole at their center, some thousands of times bigger than this one, which has a mass of about 4 million times that of our sun.

    sgra*
    This image was taken with NASA’s Chandra X-Ray Observatory.
    10 January 2007

    sgr
    This Chandra image of Sgr A* and the surrounding region is based on data from a series of observations lasting a total of about one million seconds, or almost two weeks. Such a deep observation has given scientists an unprecedented view of the supernova remnant near Sgr A* (known as Sgr A East) and the lobes of hot gas extending for a dozen light years on either side of the black hole. These lobes provide evidence for powerful eruptions occurring several times over the last ten thousand years. The image also contains several mysterious X-ray filaments, some of which may be huge magnetic structures interacting with streams of energetic electrons produced by rapidly spinning neutron stars. Such features are known as pulsar wind nebulas.
    Date 7 January 2010

    NASA Chandra Telescope
    NASA Chandra schematic
    NASA/Chandra

    Astronomers originally noticed something in the region in 2002, but the first detailed determinations of G2’s size and orbit came in 2012. The dust in the cloud has been measured at about 550 degrees Kelvin, approximately twice as hot as the surface temperature on Earth. The gas, mostly hydrogen, is about 10,000 degrees Kelvin, or almost twice as hot as the surface of the sun.

    “A star being present within the cloud would make sense, and was suggested by earlier workers trying to explain the origin of the G2 cloud, which is otherwise pretty mysterious,” Murray said.

    One idea was that the cloud might be the result of an old star losing mass. Based on the brightness of the object, the mass of the star was estimated to be pretty small (no more than about the mass of our sun), and “our models indicated that it would be insufficient to hold the cloud together against the tidal forces of the black hole,” he said.

    However, in the new study (link is external) [link would not open] appearing in the journal Astrophysical Journal Letters, the researchers found that G2 is pretty much intact after its passage near the black hole. Some of the gas does show distortion by the gravity of the black hole, but there is a core of warm gas that has remained essentially unchanged. That would indicate something significantly more massive than our sun holding it together. The authors propose that it is the result of the merger of a close binary star system (two stars in orbit around each other). Such mergers might be due to interaction with the tidal field of the black hole, and the result might be a puffed-up star whose outer atmosphere is seen as the warm core of G2 that survived passage by the black hole.

    “That proposal means that we’re seeing G2 very shortly after the merger of the two stars,” Murray said. “While that’s certainly possible, it does mean that we’re seeing it at a special and relatively short-lived time. I haven’t seen strong arguments that the object can’t be a more typical star, somewhat more massive than our sun, undergoing normal mass loss as it nears the end of its life. Continued observations should let us determine just what’s inside of G2.”

    See the full article here.

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  • richardmitnick 4:05 pm on November 15, 2014 Permalink | Reply
    Tags: , , , , NASA Chandra   

    From Chandra: “Sagittarius A*: NASA X-ray Telescopes Find Black Hole May Be a Neutrino Factory” 

    NASA Chandra

    November 13, 2014
    No Writer Credit

    Researchers have found evidence that the supermassive black hole at the center of the Milky Way may be generating neutrinos. Neutrinos are tiny particles that have virtually no mass and carry no electric charge. These particles are unusual because they can travel across the Universe without being absorbed or deflected. Scientists have long been looking for where neutrinos with high energies come from.

    sgra
    Credit NASA/CXC/Univ. of Wisconsin/Y.Bai. et al.
    Release Date November 13, 2014
    Observation Date 43 pointings from September 21, 1999 to May 18, 2009
    Observation Time 278 hours (11 days 14 hours).
    Instrument: ACIS
    Also Known As Galactic Center
    References Bai, et al, 2014, Physics Review D, 90, 063012; arXiv:1407.2243

    The supermassive black hole at the center of the Milky Way, seen in this image from NASA’s Chandra X-ray Observatory, may be producing mysterious particles called neutrinos, as described in our latest press release. Neutrinos are tiny particles that have virtually no mass and carry no electric charge. Unlike light or charged particles, neutrinos can emerge from deep within their sources and travel across the Universe without being absorbed by intervening matter or, in the case of charged particles, deflected by magnetic fields.

    While the Sun produces neutrinos that constantly bombard the Earth, there are also other neutrinos with much higher energies that are only rarely detected. Scientists have proposed that these higher-energy neutrinos are created in the most powerful events in the Universe like galaxy mergers, material falling onto supermassive black holes, and the winds around dense rotating stars called pulsars.

    Using three NASA X-ray telescopes, Chandra, Swift, and NuSTAR, scientists have found evidence for one such cosmic source for high-energy neutrinos: the 4-million-solar-mass black hole at the center of our Galaxy called Sagittarius A* (Sgr A*, for short). After comparing the arrival of high-energy neutrinos at the underground facility in Antarctica, called IceCube, with outbursts from Sgr A*, a team of researchers found a correlation. In particular, a high-energy neutrino was detected by IceCube less than three hours after astronomers witnessed the largest flare ever from Sgr A* using Chandra. Several flares from neutrino detections at IceCube also appeared within a few days of flares from the supermassive black hole that were observed with Swift and NuSTAR.

    NASA SWIFT Telescope
    NASA/Swift

    NASA NuSTAR
    NASA/Nu-STAR

    ICECUBE neutrino detector
    IceCube

    This Chandra image shows the region around Sgr A* in low, medium, and high-energy X-rays that have been colored red, green, and blue respectively. Sgr A* is located within the white area in the center of the image. The blue and orange plumes around that area may be the remains of outbursts from Sgr A* that occurred millions of years ago. The flares that are possibly associated with the IceCube neutrinos involve just the Sgr A* X-ray source.

    This latest result may also contribute to the understanding of another major puzzle in astrophysics: the source of high-energy cosmic rays. Since the charged particles that make up cosmic rays are deflected by magnetic fields in our Galaxy, scientists have been unable to pinpoint their origin. The charged particles accelerated by a shock wave near Sgr A* may be a significant source of very energetic cosmic rays.

    The paper describing these results was published in Physical Review D and is also available online. The authors of the study are Yang Bai, Amy Barger, Vernon Barger, R. Lu, Andrea Peterson, J. Salvado, all from the University of Wisconsin, in Madison, Wisconsin.

    See the full article here.

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  • richardmitnick 12:25 pm on November 11, 2014 Permalink | Reply
    Tags: , , , , NASA Chandra   

    From Chandra: A White Hole? 

    NASA Chandra

    Question of the Day! Could the supermassive black hole in Perseus be a supermassive “white” hole? In the Chandra X-ray image, the point is white, and in an X-ray photo, the white means that we can’t pass the object?

    white

    Answer: The object at the center of the X-ray image acts like a black hole, i.e. a very massive, very dense object that light cannot escape from. For example, the jets of material blown out by the object at the center of the galaxy should come from a black hole. Astronomers cannot think of any other object that can cause jets which are this large.

    The black hole shows up as a white dot because of the hot, dense gas spinning around a disk around the black hole. This hot gas glows in X-rays. We don’t see X-rays from the black hole itself, which would look black in this image, but is far too small to be detectable in this image.

    It is important to note that the X-rays and jets are not coming from the black hole itself, but from the surrounding matter, likely an accretion disk, in some way that we do not yet understand. 

    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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