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  • richardmitnick 8:38 pm on April 28, 2016 Permalink | Reply
    Tags: , , NASA Chandra, Probing Dark Energy with Clusters   

    From Chandra: “Probing Dark Energy with Clusters: ‘Russian Doll’ Galaxy Clusters Reveal Information About Dark Energy” 

    NASA Chandra Banner

    NASA Chandra Telescope

    NASA Chandra

    April 28, 2016

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    Composite

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    X-ray

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    Optical

    Fast Facts for Abell 1835:
    Credit X-ray: NASA/CXC/Univ. of Alabama/A. Morandi et al; Optical: SDSS, NASA/STScI
    Release Date April 28, 2016
    Observation Dates 7 Dec 2005, 24 Jul and 25 Aug 2006

    Fast Facts for MS 1455.0+2232:
    Credit X-ray: NASA/CXC/Univ. of Alabama/A. Morandi et al; Optical: SDSS, NASA/STScI
    Release Date April 28, 2016
    Observation Dates 19 May 2000, 05 Sep 2003, 23 Mar 2007

    Fast Facts for RXJ 1347.5-1145:
    Credit X-ray: NASA/CXC/Univ. of Alabama/A. Morandi et al; Optical: SDSS, NASA/STScI
    Release Date April 28, 2016
    Observation Dates 3 Sep 2003, 16 Mar, 14 May and 11 Dec 2012

    Fast Facts for ZWCL 3146:
    Credit X-ray: NASA/CXC/Univ. of Alabama/A. Morandi et al; Optical: SDSS, NASA/STScI
    Release Date April 28, 2016
    Observation Dates 10 May 2000, 18 Jan 2008

    Researchers are using a large sample of galaxy cluster to investigate dark energy.

    The details of X-ray emission from over 300 galaxy clusters were obtained with Chandra.

    The galaxy clusters range in distance from about 760 million to 8.7 billion light years from Earth.

    The study shows that dark energy has not changed over billions of years.

    These four galaxy clusters were part of a large survey of over 300 clusters used to investigate dark energy, the mysterious energy that is currently driving the accelerating expansion of the Universe, as described in our latest press release. In these composite images, X-rays from NASA’s Chandra X-ray Observatory (purple) have been combined with optical light from the Hubble Space Telescope and Sloan Digital Sky Survey (red, green, and blue).

    NASA/ESA Hubble Telescope
    NASA/ESA Hubble Telescope

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

    Researchers used a novel technique that takes advantage of the observation that the outer reaches of galaxy clusters, the largest structures in the universe held together by gravity, show similarity in their X-ray emission profiles and sizes. That is, more massive clusters are simply scaled up versions of less massive ones, similar to Russian dolls that nest inside one another.

    The amount of matter in the Universe, which is dominated by the unseen substance called dark matter, and the properties of dark energy (what astronomers call cosmological parameters) affect the rate of expansion of the Universe and, therefore, how the distances to objects change with time. If the cosmological parameters used are incorrect and a cluster is inferred to be traveling away faster than the correct value, then a cluster will appear to be larger and fainter due to this “Russian doll” property. If the cluster is inferred to be traveling away more slowly than the correct value, the cluster will be smaller and brighter than a cluster according to theory.

    These latest results confirm earlier studies that the amount of dark energy has not changed over billions of years. They also support the idea that dark energy is best explained by the “cosmological constant,” which Einstein first proposed and is equivalent to the energy of empty space.

    The galaxy clusters in this large sample ranged in distance from about 760 million to 8.7 billion light years from Earth, providing astronomers with information about the era where dark energy caused the once-decelerating expansion of the Universe to accelerate.

    The X-ray emission in the outer parts of galaxy clusters is faint because the gas is diffuse there. To deal with this issue in this study, the X-ray signal from different clusters was added together. Regions near the centers of the clusters are excluded from the analysis because of large differences between the properties of different clusters caused by supermassive black hole outbursts, the cooling of gas and the formation of stars.

    A paper describing these results by Andrea Morandi and Ming Sun (University of Alabama at Huntsville) appeared in the April 11th, 2016 issue of the Monthly Notices of the Royal Astronomical Society journal and is available online*.

    *Science paper:
    Probing dark energy via galaxy cluster outskirts

    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 11:06 pm on March 10, 2016 Permalink | Reply
    Tags: , , , NASA Chandra   

    From Chandra: “MACS J0416.1-2403 and MACS J0717.5+3745: Telescopes Combine to Push Frontier on Galaxy Clusters” 

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    NASA Chandra Telescope

    NASA Chandra

    MACS J0416.1-2403 and MACS J0717.5+3745
    Credit X-ray: NASA/CXC/SAO/G.Ogrean et al.; Optical: NASA/STScI; Radio: NRAO/AUI/NSF
    Release Date March 10, 2016

    These two galaxy clusters are part of the “Frontier Fields” project that obtains long observations with multiple telescopes.

    Galaxy clusters are important because they are the largest structures in the Universe held together by gravity.

    Both of these objects are sites where multiple galaxy clusters are colliding.

    X-rays from Chandra reveal the massive amounts of hot gas that pervade each galaxy cluster.

    Galaxy clusters are enormous collections of hundreds or even thousands of galaxies and vast reservoirs of hot gas embedded in massive clouds of dark matter, invisible material that does not emit or absorb light but can be detected through its gravitational effects. These cosmic giants are not merely novelties of size or girth – rather they represent pathways to understanding how our entire universe evolved in the past and where it may be heading in the future.

    To learn more about clusters, including how they grow via collisions, astronomers have used some of the world’s most powerful telescopes, looking at different types of light. They have focused long observations with these telescopes on a half dozen galaxy clusters. The name for this galaxy cluster project is the Frontier Fields.

    Two of these Frontier Fields galaxy clusters, MACS J0416.1-2403 (abbreviated MACS J0416) and MACS J0717.5+3745 (MACS J0717 for short) are featured here in a pair of multi-wavelength images.

    Located about 4.3 billion light years from Earth, MACS J0416 is a pair of colliding galaxy clusters that will eventually combine to form an even bigger cluster. MACS J0717, one of the most complex and distorted galaxy clusters known, is the site of a collision between four clusters. It is located about 5.4 billion light years away from Earth.

    These new images of MACS J0416 and MACS J0717 contain data from three different telescopes: NASA’s Chandra X-ray Observatory (diffuse emission in blue), Hubble Space Telescope (red, green, and blue), and the NSF’s [NRAO] Jansky Very Large Array (diffuse emission in pink). Where the X-ray and radio emission overlap the image appears purple. Astronomers also used data from the the Giant Metrewave Radio Telescope [GMRT] in India in studying the properties of MACS J0416.

    NASA Hubble Telescope
    NASA/ESA Hubble

    NRAO VLA
    NRAO/VLA

    Giant Metrewave Radio Telescope
    GMRT

    The Chandra data shows gas in the merging clusters with temperatures of millions of degrees. The optical data shows galaxies in the clusters and other, more distant, galaxies lying behind the clusters. Some of these background galaxies are highly distorted because of gravitational lensing, the bending of light by massive objects. This effect can also magnify the light from these objects, enabling astronomers to study background galaxies that would otherwise be too faint to detect. Finally, the structures in the radio data trace enormous shock waves and turbulence. The shocks are similar to sonic booms, generated by the mergers of the clusters.

    New results from multi-wavelength studies of MACS J0416 and MACS J0717, described in two separate papers, are included below.

    An open question for astronomers about MACS J0416 has been: are we seeing a collision in these clusters that is about to happen or one that has already taken place? Until recently, scientists have been unable to distinguish between these two explanations. Now, the combined data from these various telescopes is providing new answers.

    In MACS J0416 the dark matter (which leaves its gravitational imprint in the optical data) and the hot gas (detected by Chandra) line up well with each other. This suggests that the clusters have been caught before colliding. If the clusters were being observed after colliding the dark matter and hot gas should separate from each other, as seen in the famous colliding cluster system known as the Bullet Cluster.

    Bullet Cluster NASA Chandra NASA ESA Hubble
    Bullet Cluster. NASA/Chandra NASA/ESA Hubble

    The cluster in the upper left contains a compact core of hot gas, most easily seen in a specially processed image, and also shows evidence of a nearby cavity, or hole in the X-ray emitting gas. The presence of these structures also suggests that a major collision has not occurred recently, otherwise these features would likely have been disrupted. Finally, the lack of sharp structures in the radio image provides more evidence that a collision has not yet occurred.

    In the cluster located in the lower right, the observers have noted a sharp change in density on the southern edge of the cluster. This change in density is most likely caused by a collision between this cluster and a less massive structure located further to the lower right.

    In Jansky Very Large Array images of this cluster, seven gravitationally-lensed sources are observed, all point sources or sources that are barely larger than points. This makes MACS J0717 the cluster with the highest number of known lensed radio sources. Two of these lensed sources are also detected in the Chandra image. The authors are only aware of two other lensed X-ray sources behind a galaxy cluster.

    All of the lensed radio sources are galaxies located between 7.8 and 10.4 billion light years away from Earth. The brightness of the galaxies at radio wavelengths shows that they contain stars forming at high rates. Without the amplification by lensing, some of these radio sources would be too faint to detect with typical radio observations. The two lensed X-ray sources detected in the Chandra images are likely active galactic nuclei (AGN) at the center of galaxies. AGN are compact, luminous sources powered by gas heated to millions of degrees as it falls toward supermassive black holes. These two X-ray sources would have been detected without lensing but would have been two or three times fainter.

    The large arcs of radio emission in MACS J0717 are very different from those in MACS J0416 because of shock waves arising from the multiple collisions occurring in the former object. The X-ray emission in MACS J0717 has more clumps because there are four clusters violently colliding.

    Georgiana Ogrean, who was at Harvard-Smithsonian Center for Astrophysics while leading the work on MACS J0416 research, is currently at Stanford University. The paper describing these results was published in the October 20th, 2015 issue of the Astrophysical Journal and is available online. The research on MACS J0717 was led by Reinout van Weeren from the Harvard-Smithsonian Center for Astrophysics, and was published in the February 1st, 2016 issue of 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 9:28 pm on February 16, 2016 Permalink | Reply
    Tags: , , , NASA Chandra   

    From Chandra: “B3 0727+409: Glow from the Big Bang Allows Discovery of Distant Black Hole Jet” 

    NASA Chandra Banner

    NASA Chandra Telescope

    NASA Chandra

    February 16, 2016
    No writer credit found

    Black Hole Jet B3 0727 409 Glow from the Big Bang Allows Discovery
    Credit X-ray: NASA/CXC/ISAS/A.Simionescu et al, Optical: DSS
    Release Date February 16, 2016

    A jet from a very distant black hole, called B3 0727+409, has been found using the Chandra X-ray Observatory. The light from this jet was emitted just 2.7 billion light years after the Big Bang when the Universe was only one fifth its current age. Jets in the early Universe such as this one give astronomers a way to probe the growth of black holes at a very early epoch. Typically, such distant jets are discovered in radio waves first, but not B3 0727+409 that was first found by Chandra.

    A jet from a very distant black hole being illuminated by the leftover glow from the Big Bang, known as the cosmic microwave background (CMB), has been found as described in our latest press release.

    Cosmic Background Radiation Planck
    CMB per ESA/Planck

    ESA Planck
    ESA/Planck

    Astronomers using NASA’s Chandra X-ray Observatory discovered this faraway jet serendipitously when looking at another source in Chandra’s field of view.

    Jets in the early Universe such as this one, known as B3 0727+409, give astronomers a way to probe the growth of black holes at a very early epoch in the cosmos. The light from B3 0727+409 was emitted about 2.7 billion years after the Big Bang when the Universe was only about one fifth of its current age.

    This main panel graphic shows Chandra’s X-ray data that have been combined with an optical image from the [ESO]Digitized Sky Survey. (Note that the two sources near the center of the image do not represent a double source, but rather a coincidental alignment of the distant jet and a foreground galaxy.)

    Caltech Palomar  Samuel Oschin 48 inch Telescope
    Caltech Palomar  Samuel Oschin 48 inch Telescope Interior with Edwin Hubble
    UK Schmidt Telescope Exterior
    AAO UK Schmidt Telescope Interior
    Above, Caltech Palomar Samuel Oschin 48″ Schmidt telescope. Below, UK Schmidt telescope, both used in the DSS Survey.

    The inset shows more detail of the X-ray emission from the jet detected by Chandra. The length of the jet in 0727+409 is at least 300,000 light years. Many long jets emitted by supermassive black holes have been detected in the nearby Universe, but exactly how these jets give off X-rays has remained a matter of debate. In B3 0727+409, it appears that the CMB is being boosted to X-ray wavelengths.

    Scientists think that as the electrons in the jet fly from the black hole at close to the speed of light, they move through the sea of CMB radiation and collide with microwave photons. This boosts the energy of the photons up into the X-ray band to be detected by Chandra. If this is the case, it implies that the electrons in the B3 0727+409 jet must keep moving at nearly the speed of light for hundreds of thousands of light years.

    The significance of this discovery is heightened because astronomers essentially stumbled across this jet while observing a galaxy cluster in the field. Historically, such distant jets have been discovered in radio waves first, and then followed up with X-ray observations to look for high-energy emission. If bright X-ray jets can exist with very faint or undetected radio counterparts, it means that there could be many more of them out there because astronomers haven’t been systematically looking for them.

    A paper describing these results was published in the 2016 January 1st issue of The Astrophysical Journal Letters and is available online. The authors are Aurora Simionescu (Institute of Space and Astronautical Science, Kanagawa, Japan), Lukasz Stawarz (Jagiellonian University, Kraków, Poland), Yuto Ichinohe (Institute of Space and Astronautical Science, Kanagawa, Japan), Teddy Cheung (Naval Research Laboratory, Washington, DC), Marek Jamrozy (Jagiellonian University, Kraków, Poland), Aneta Siemiginowska (Harvard-Smithsonian Center for Astrophysics, Cambridge, MA), Kouichi Hagino (Institute of Space and Astronautical Science, Kanagawa, Japan), Poshak Gandhi (University of Southampton, Southampton, UK) and Norbert Werner (Stanford University, Stanford, CA).

    See the full article here .

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

     
  • richardmitnick 3:53 pm on February 2, 2016 Permalink | Reply
    Tags: , , , Far Away, NASA Chandra, Pictor A: Blast from Black Hole in a Galaxy Far   

    From Chandra: “Pictor A: Blast from Black Hole in a Galaxy Far, Far Away” 

    NASA Chandra

    February 2, 2016
    Pictor A Blast from Black Hole in a Galaxy Far, Far Away
    Credit X-ray: NASA/CXC/Univ of Hertfordshire/M.Hardcastle et al., Radio: CSIRO/ATNF/ATCA
    Release Date February 2, 2016

    A giant jet spanning continuously for over 300,000 light years is seen blasting out of the galaxy Pictor A.

    A new composite image shows this jet in X-rays (blue) and radio waves (red). [see the original full article for more images.]

    In addition to the main jet, there is evidence for a jet moving in the opposite direction.

    Chandra observations at various times over a 15-year period provide new details of this impressive system.

    The Star Wars franchise has featured the fictitious “Death Star,” which can shoot powerful beams of radiation across space. The Universe, however, produces phenomena that often surpass what science fiction can conjure.

    The Pictor A galaxy is one such impressive object. This galaxy, located nearly 500 million light years from Earth, contains a supermassive black hole at its center. A huge amount of gravitational energy is released as material swirls towards the event horizon, the point of no return for infalling material. This energy produces an enormous beam, or jet, of particles traveling at nearly the speed of light into intergalactic space.

    To obtain images of this jet, scientists used NASA’s Chandra X-ray Observatory at various times over 15 years. Chandra’s X-ray data (blue) have been combined with radio data from the Australia Telescope Compact Array (red) in this new composite image.

    CSIRO Australia Compact Array
    Australia Telescope Compact Array

    By studying the details of the structure seen in both X-rays and radio waves, scientists seek to gain a deeper understanding of these huge collimated blasts.

    The jet [to the right] in Pictor A is the one that is closest to us. It displays continuous X-ray emission over a distance of 300,000 light years. By comparison, the entire Milky Way is about 100,000 light years in diameter. Because of its relative proximity and Chandra’s ability to make detailed X-ray images, scientists can look at detailed features in the jet and test ideas of how the X-ray emission is produced.

    In addition to the prominent jet seen pointing to the right in the image, researchers report evidence for another jet pointing in the opposite direction, known as a “counterjet”. While tentative evidence for this counterjet had been previously reported, these new Chandra data confirm its existence. The relative faintness of the counterjet compared to the jet is likely due to the motion of the counterjet away from the line of sight to the Earth.

    The labeled image shows the location of the supermassive black hole, the jet and the counterjet. Also labeled is a “radio lobe” where the jet is pushing into surrounding gas and a “hotspot” caused by shock waves – akin to sonic booms from a supersonic aircraft – near the tip of the jet.

    The detailed properties of the jet and counterjet observed with Chandra show that their X-ray emission likely comes from electrons spiraling around magnetic field lines, a process called synchrotron emission. In this case, the electrons must be continuously re-accelerated as they move out along the jet. How this occurs is not well understood

    The researchers ruled out a different mechanism for producing the jet’s X-ray emission. In that scenario, electrons flying away from the black hole in the jet at near the speed of light move through the sea of cosmic background radiation (CMB) left over from the hot early phase of the Universe after the Big Bang3.

    Cosmic Background Radiation Planck
    CMB per ESA/Planck

    ESA Planck
    ESA/Planck

    When a fast-moving electron collides with one of these CMB photons, it can boost the photon’s energy up into the X-ray band.

    The X-ray brightness of the jet depends on the power in the beam of electrons and the intensity of the background radiation. The relative brightness of the X-rays coming from the jet and counterjet in Pictor A do not match what is expected in this process involving the CMB, and effectively eliminate it as the source of the X-ray production in the jet.

    A paper describing these results will be published in the Monthly Notices of the Royal Astronomical Society and is available online. The authors are Martin Hardcastle from the University of Hertfordshire in the UK, Emil Lenc from the University of Sydney in Australia, Mark Birkinshaw from the University of Bristol in the UK, Judith Croston from the University of Southampton in the UK, Joanna Goodger from the University of Hertfordshire, Herman Marshall from the Massachusetts Institute of Technology in Cambridge, MA, Eric Perlman from the Florida Institute of Technology, Aneta Siemiginowska from the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA, Lukasz Stawarz from Jagiellonian University in Poland and Diana Worrall from the University of Bristol.

    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 4:48 pm on January 29, 2016 Permalink | Reply
    Tags: , , NASA Chandra, X-ray jet   

    From AAS NOVA: “Surprise Discovery of an X-Ray Jet” 

    AASNOVA

    American Astronomical Society

    29 January 2016
    Susanna Kohler

    Xray jet Chandra
    Chandra X-ray image of the quasar B3 0727+409. This high-redshift quasar jet is unusual in that there is very little radio emission associated with it. Very Large Array [VLA] radio observations are shown in green contours; click for the full view! [Simionescu et al. 2016]

    Accreting, supermassive black holes that reside at galactic centers can power enormous jets, bright enough to be observed from vast distances away. The recent discovery of such a jet in X-ray wavelengths, without an apparent radio counterpart, has interesting implications for our understanding of how these distant behemoths shine.

    An Excess of X-Rays

    Quasar B3 0727+409 was serendipitously discovered to host an X-ray jet when a group of scientists, led by Aurora Simionescu (Institute of Space and Astronautical Sciences of the Japan Aerospace Exploration Agency), was examining Chandra observations of another object.

    NASA Chandra Telescope
    NASA/Chandra

    NRAO VLA
    Karl V Jansky NRAO VLA

    The Chandra data reveal bright, compact, extended emission from the core of quasar B3 0727+409, with a projected length of ~100 kpc. There also appears to be further X-ray emission at a distance of ~280 kpc, which Simionescu and collaborators speculate may be the terminal hotspot of the jet.

    The quasar is located at a redshift of z=2.5 — which makes this jet one of only a few high-redshift X-ray jets known to date. But what makes it especially intriguing is that, though the authors searched through both recent and archival radio observations of the quasar, the only radio counterpart they could find was a small feature close to the quasar core (which may be a knot in the jet). Unlike what is typical of quasar jets, there was no significant additional radio emission coinciding with the rest of the X-ray jet.

    Making Jets Shine

    What does this mean? To answer this, we must consider one of the outstanding questions about quasar jets: what radiation processes dominate their emission? One process possibly contributing to the X-ray emission is inverse-Compton scattering of low-energy cosmic microwave background (CMB) photons off of the electrons in the jet; these photons can scatter up to X-ray energies.

    Interestingly, there’s a testable prediction associated with this mechanism. If this process dominates the X-ray emission of quasar jets, then the X-ray-to-radio flux ratio of the jet would increase with redshift as (1+z)4, due to the increased density of CMB photons at higher redshift.

    Thus far, our limited detections of high-redshift X-ray quasars have made it difficult to test this prediction, but quasar B3 0727+409 provides an extremely useful data point. When the authors model the radio-to-X-ray flux ratio for the jet, they find that it’s entirely consistent with the inverse-Compton scenario.

    This discovery suggests that the inverse-Compton mechanism may indeed be what dominates the X-ray radiation from jets like this one. And since our current observing strategies focus on Chandra follow-up of known bright radio jets, this could mean that there is an entire population of similar systems — with bright X-ray and faint radio emission — that we have missed!
    Citation

    A. Simionescu et al 2016 ApJ 816 L15. doi:10.3847/2041-8205/816/1/L15

    See the full article here .

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  • richardmitnick 4:12 pm on January 7, 2016 Permalink | Reply
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    From Hubble: “NASA’s Great Observatories Weigh Massive Young Galaxy Cluster” 

    NASA Hubble Telescope

    Hubble

    January 7, 2016
    CONTACT

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

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4514
    villard@stsci.edu

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

    Mark Brodwin
    University of Missouri, Kansas City, Missouri
    brodwinm@umkc.edu

    Temp 1
    Hubble, Chandra, Spitzer Composite of Massive Galaxy Cluster IDCS J1426.5+3508

    Temp 2
    HST Image of Massive Galaxy Cluster IDCS J1426.5+3508

    Temp 3
    Compass and Scale Image of Massive Galaxy Cluster IDCS J1426.5+3508

    Astronomers have used data from three of NASA’s Great Observatories to make the most detailed study yet of an extremely massive young galaxy cluster. This rare galaxy cluster, which is located 10 billion light-years from Earth, is almost as massive as 500 trillion suns. This object has important implications for understanding how these megastructures formed and evolved early in the universe.

    The galaxy cluster, called IDCS J1426.5+3508 (IDCS 1426 for short), is so far away that the light detected is from when the universe was roughly a quarter of its current age. It is the most massive galaxy cluster detected at such an early age.

    First discovered by the Spitzer Space Telescope in 2012, IDCS 1426 was then observed using the Hubble Space Telescope and the Keck Observatory to determine its distance.

    NASA Spitzer Telescope
    NASA/Spitzer

    Keck Observatory
    Keck Observatory Interior
    Keck Observatory

    Observations from the Combined Array for Millimeter-wave Astronomy indicated it was extremely massive.

    Caltech Combined Array for Millimeter Astronomy
    Caltech/Combined Array for Millimeter-wave Astronomy

    New data from the Chandra X-ray Observatory confirm the galaxy cluster mass and show that about 90 percent of the mass of the cluster is in the form of dark matter, a mysterious substance detected so far only through its gravitational pull on normal matter composed of atoms.

    NASA Chandra Telescope
    NASA/Chandra

    “We are really pushing the boundaries with this discovery,” said Mark Brodwin of the University of Missouri at Kansas City, who led the study. “As one of the earliest massive structures to form in the universe, this cluster sets a high bar for theories that attempt to explain how clusters and galaxies evolve.”

    Galaxy clusters are the largest objects in the universe bound together by gravity. Because of their sheer size, scientists think it should take several billion years for them to form. The distance of IDCS J1426 means astronomers are observing it when the universe was only 3.8 billion years old, implying that the cluster is seen at a very young age.

    The data from Chandra reveal a bright knot of X-rays near the middle of the cluster, but not exactly at its center. This overdense core has been dislodged from the cluster center, possibly by a merger with another developing cluster 500 million years prior. Such a merger would cause the X-ray-emitting, hot gas to slosh around like wine in a glass that is tipped from side to side.

    “Mergers with other groups and clusters of galaxies should have been more common so early in the history of the universe,” said co-author Michael McDonald of the Massachusetts Institute of Technology in Cambridge, Massachusetts. “That appears to have played an important part in this young cluster’s rapid formation.”

    Aside from this cool core, the hot gas in the rest of the cluster is very smooth and symmetric. This is another indication that IDCS 1426 formed very rapidly. In addition, astronomers found possible evidence that the abundance of elements heavier than hydrogen and helium in the hot gas is unusually low. This suggests that this galaxy cluster might still be in the process of enriching its hot gas with these elements as supernovae create heavier elements and blast them out of individual galaxies.

    “The presence of this massive galaxy cluster in the early universe doesn’t upset our current understanding of cosmology,” said co-author of Anthony Gonzalez of the University of Florida in Gainesville, Florida. “It does, however, give us more information to work with as we refine our models.”

    Evidence for other massive galaxy clusters at early times has been found, but none of these matches IDCS 1426, with its combination of mass and youth. The mass determination used three independent methods: a measurement of the mass needed to confine the hot X-ray-emitting gas to the cluster, the imprint of the cluster’s gaseous mass on the cosmic microwave background radiation [CMB], and the observed distortions in the shapes of galaxies behind the cluster, which are caused by the bending of light from the galaxies by the gravity of the cluster.

    CMB Planck ESA
    CMB per ESA/Planck

    ESA Planck
    ESA/Planck

    These results were presented at the 227th American Astronomical Society meeting being held in Kissimmee, Florida. A paper describing these results has been accepted for publication in The Astrophysical Journal and is available online. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA’s Science Mission Directorate in Washington, D.C. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations. The Spitzer Space Telescope is managed by NASA’s Jet Propulsion Laboratory in Pasadena, California. The Spitzer Science Center at the California Institute of Technology in Pasadena conducts science operations. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.

    Data Description:

    The HST data were taken from the following proposals: 11663 : M. Brodwin (University of Missouri, Kansas City), P. Eisenhardt (JPL), A. Stanford (UC Davis/LLNL), D. Stern (JPL), L. Moustakas (JPL), A. Dey (NOAO), B. Jannuzi (University of Arizona/NOAO), and A. Gonzalez (University of Florida, Gainesville);

    12203: A. Stanford (UC Davis/LLNL), M. Brodwin (University of Missouri, Kansas City), A. Gonzalez (University of Florida, Gainesville), A. Dey (NOAO), D. Stern (JPL), G. Zeimann (Penn State University), and P. Eisenhardt and L. Moustakas (JPL);

    and 12994: A. Gonzalez (University of Florida, Gainesville), M. Brodwin (University of Missouri, Kansas City), A. Stanford (UC Davis/LLNL), J. Rhodes and D. Stern (JPL), P. Eisenhardt (JPL), C. Fedeli (University of Florida), G. Zeimann (Penn State University), A. Dey (NOAO), and D. Marrone (University of Arizona).

    The science team includes M. Brodwin (University of Missouri, Kansas City), M. McDonald (MIT), A. Gonzalez (University of Florida, Gainesville), A. Stanford (UC Davis/LLNL), P. Eisenhardt and D. Stern (JPL), and G. Zeimann (Penn State University).
    Instruments/Filters:
    ACS/WFC F606W (V)
    ACS//WFC F814W(I)
    WFC3/IR F160W (H)

    NASA Hubble ACS
    ACS

    NASA Hubble WFC3
    WFC3

    See the full article here .

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    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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  • richardmitnick 5:48 pm on January 5, 2016 Permalink | Reply
    Tags: , , NASA Chandra, NGC 5195 Galaxy   

    From Chandra- “NGC 5195: NASA’s Chandra Finds Supermassive Black Hole Burping Nearby” 

    NASA Chandra

    January 5, 2016
    No writer credit found

    Temp 1
    Credit X-ray: NASA/CXC/Univ of Texas/E.Schlegel et al; Optical: NASA/STScI
    Release Date January 5, 2016

    One of the nearest supermassive black holes to Earth with active powerful outbursts has been discovered.

    Such outbursts are part of the “feedback” process that is important to the evolution of the black hole and its host galaxy.

    Evidence for these eruptions was found with the Chandra X-ray Observatory in the galaxy NGC 5195.

    Two arcs in the X-ray data suggest separate eruptions from the black hole occurred millions of years ago.

    Astronomers have used NASA’s Chandra X-ray Observatory to discover one of the nearest supermassive black holes to Earth that is currently undergoing powerful outbursts, as described in our latest press release. This galactic burping was found in the Messier 51 galaxy, which is located about 26 million light years from Earth and, contains a large spiral galaxy NGC 5194 (also known by its nickname of the “Whirlpool”), merging with a smaller companion galaxy NGC 5195.

    This main panel of this graphic shows M51 in visible light data from the Hubble Space Telescope (red, green, and blue).

    NASA Hubble Telescope
    NASA/ESA Hubble

    The box at the top of the image outlines the field of view by Chandra in the latest study, which focuses on the smaller component of M51, NGC 5195.

    The inset to the right shows the details of the Chandra data (blue) of this region. Researchers found a pair of arcs in X-ray emission close to the center of the galaxy, which they interpret as two outbursts from the galaxy’s supermassive black hole (mouse over annotated image for additional information). The authors estimate that it took about one to three million years for the inner arc to reach its current position, and three to six million years for the outer arc.

    Temp 1
    X-ray close-up

    Just outside the outer X-ray arc is a slender region of hydrogen emission detected in an optical image. This suggests that the X-ray emitting gas has “snow-plowed” or swept-up the hydrogen gas from the center of the galaxy. This is a clear case where a supermassive black hole is affecting its host galaxy, in a phenomenon that astronomers called “feedback.”

    This arc of hydrogen gas contains what appears to be two or three small “HII regions.” An HII (pronounced “H-two”) region is created when the radiation from hot, young stars strips away the electrons from neutral hydrogen atoms (HI) to form clouds of ionized hydrogen (HII). This suggests that the outer arc has plowed up enough material to trigger the formation of new stars.

    The outbursts of the supermassive black hole in NGC 5195 may have been triggered by the interaction of this galaxy with the large spiral galaxy in M51, causing gas to be disrupted and then funneled down towards the black hole.

    These results were presented at the 227th meeting of the American Astronomical Society meeting in Kissimmee, Florida. They are also in a paper submitted to The Astrophysical Journal and the authors are Eric Schlegel (University of Texas at San Antonio), Christine Jones (Harvard-Smithsonian Center for Astrophysics), Marie Marachek (CfA), and Laura Vega (Fisk University and Vanderbilt University Bridge Program).

    See the full article here .

    Another view of NGC 5195, this from NASA/ESA Hubble
    3
    A Hubble Space Telescope (HST) image of Messier 51. M51A (the Whirlpool Galaxy) is the spiral galaxy on the left. NGC 5195 is the galaxy in the top right corner. Credit:HST/STScI/AURA/NASA/ESA.

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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 2:31 pm on December 25, 2015 Permalink | Reply
    Tags: , , , NASA Chandra   

    From CfA: “Magnetic Fields in Powerful Radio Jets” 

    Smithsonian Astrophysical Observatory
    Smithsonian Astrophysical Observatory

    December 25, 2015
    No Writer Credit

    1
    X-ray jets from the galaxy Pictoris A. The greyscale image was taken by the Chandra X-ray Observatory and reveals the detailed X-ray structure of the jets, which extend over nearly one million light-years. The red contours show the radio emission. Astronomers analyzing these and other data have concluded that the X-ray emission is produced by rapidly moving charged particles in magnetic fields. NASA/Chandra, Hardcastle et al.

    Super-massive black holes at the centers of galaxies can spawn tremendous bipolar jets when matter in the vicinity forms a hot, accreting disk around the black hole. The rapidly moving charged particles in the jets radiate when they are deflected by magnetic fields; these jets were discovered at radio wavelengths several decades ago. In the most dramatic cases, the energetic particles move at speeds close to the speed of light and extend over hundreds of thousands of light-years, well beyond the visible boundaries of the galaxy. The physical processes that drive these jets and cause them to radiate are among the most important outstanding problems of modern astrophysics.

    One of the most significant and unexpected discoveries of the Chandra X-ray Observatory was that bright X-rays are also emitted by these jets.

    NASA Chandra Telescope
    NASA Chandra

    The X-rays are also produced by the acceleration of charged particles, at least according to some models, but there are other possible mechanisms as well. Fast-moving particles can scatter background light, boosting it into the X-ray band. Alternatively, shocks can generate X-ray emission (or at least a significant portion of it), either as the jets interact with stellar winds and interstellar medium or, within the jet, as a consequence of jet variability, instability, turbulence, or other phenomena.

    2
    Original NASA description: The Hubble Space Telescope imaged this view in February 1995. The arcing, graceful structure is actually a bow shock about half a light-year across, created from the wind from the star L.L. Orionis colliding with the Orion Nebula flow.
    Date February 1995
    Source NASA

    NASA Hubble Telescope
    NASA/ESA Hubble

    CfA astronomer Aneta Siemiginowska and her colleagues have studied the bright radio jet galaxy Pictoris A, located almost five hundred million light-years away, using very deep Chandra measurements – the observations used an accumulated total of over four days of time, spread over a fourteen year period. These data enabled the first detailed analysis of the spectral character of the emission all along the jets. The emission turns out to be remarkably uniform everywhere, something that is extremely unlikely if scattering were responsible, but which is a natural consequence of the magnetic field process. The scientists therefore reject the scattering model in favor of the latter. However, the jets do have within them many small clumps, internal structures, and lobes. Shocks and/or scattering are possible explanations for the emission in some of these structures. Although these new results represent some dramatic improvements in our understanding of Pic A, high-resolution radio measurements of a large sample of similar jets are now needed to refine and extend the models. Large-scale X-ray jets, for example, have been also detected in very distant quasars. The results from Pic A, together with future Chandra observations, will help astronomers determine the extent to which these distant jets also rely on the same processes, or if they invoke other ones.

    Reference(s):

    “Deep Chandra Observations of Pictor A,” M.J. Hardcastle, E. Lenc, M. Birkinshaw, J.H. Croston, J.L. Goodger, H.L. Marshall, E.S. Perlman, A. Siemiginowska, Ł. Stawarz, and D.M. Worrall, MNRAS 2015 (in press).

    See the full article here .

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    About CfA

    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy. The long relationship between the two organizations, which began when the SAO moved its headquarters to Cambridge in 1955, was formalized by the establishment of a joint center in 1973. The CfA’s history of accomplishments in astronomy and astrophysics is reflected in a wide range of awards and prizes received by individual CfA scientists.

    Today, some 300 Smithsonian and Harvard scientists cooperate in broad programs of astrophysical research supported by Federal appropriations and University funds as well as contracts and grants from government agencies. These scientific investigations, touching on almost all major topics in astronomy, are organized into the following divisions, scientific departments and service groups.

     
  • richardmitnick 8:32 pm on December 21, 2015 Permalink | Reply
    Tags: , , NASA Chandra   

    From Chandra: “Zwicky 8338: Chandra Finds Remarkable Galactic Ribbon Unfurled” 

    NASA Chandra

    December 21, 2015

    Temp 1
    Composite

    2
    X-ray

    3
    Optical
    Credit X-ray: NASA/CXC/University of Bonn/G. Schellenberger et al; Optical: INT
    Release Date December 21, 2015

    A gigantic tail of X-ray emission has been found behind a galaxy plowing through the galaxy cluster Zwicky 8338.

    With a length of at least 250,000 light years, this is likely the largest such tail ever detected.

    Scientists used Chandra to discover the tail, study its properties and learn how this X-ray tail affects its cluster environment.

    An extraordinary ribbon of hot gas trailing behind a galaxy like a tail has been discovered using data from NASA’s Chandra X-ray Observatory, as described in our latest press release. This ribbon, or X-ray tail, is likely due to gas stripped from the galaxy as it moves through a vast cloud of hot intergalactic gas. With a length of at least 250,000 light years, it is likely the largest such tail ever detected. In this new composite image, X-rays from Chandra (blue) have been combined with data in visible light from the Isaac Newton Group of Telescopes (yellow) in the Canary Islands, Spain.

    The tail is located in the galaxy cluster Zwicky 8338, which is almost 700 million light years from Earth. The length of the tail is more than twice the diameter of the entire Milky Way galaxy. The tail contains gas at temperatures of about ten million degrees, about twenty million degrees cooler than the intergalactic gas, but still hot enough to glow brightly in X-rays that Chandra can detect.

    The researchers think the tail was created as a galaxy known as CGCG254-021, or perhaps a group of galaxies dominated by this large galaxy, plowed through the hot gas in Zwicky 8338. The pressure exerted by this rapid motion caused gas to be stripped away from the galaxy.

    In images from Chandra and the NSF’s Karl Jansky Very Large Array [a part of NRAO] (not shown in composite), the galaxy CGCG254-021 appears to be moving towards the bottom of the image with the tail following behind.

    NRAO VLA
    NRAO/Karl Jansky Very Large Array

    There is a significant gap between the X-ray tail and the galaxy, the largest ever seen. The significant separation between the galaxy and the tail might be evidence that the gas has been completely stripped off the galaxy.

    Astronomers were also able to learn more about the interactions of the system by carefully examining the properties of the galaxy and its tail. The tail has a brighter spot, referred to as its “head”. Behind this head is the tail of diffuse X-ray emission. The gas in the head may be cooler and richer in elements heavier than helium than the rest of the tail. In front of the head there are hints of a bow shock, similar to a shock wave formed by a supersonic plane and in front of the bow shock is the galaxy CGCG254-021.

    Independent research involving observations at infrared wavelengths indicates that CGCG254-021 has the highest mass of all galaxies in Zwicky 8338. The infrared observations, together with models for how galaxies evolve, also imply that among the galaxies in the cluster, CGCG254-021 had by far the highest rate of stars forming in the recent past. However, there is no evidence for new star formation, possibly because gas has been depleted in forming the tail.

    The paper describing these results was published in the November 2015 issue of Astronomy and Astrophysics and is also available online. The authors of the paper are Gerrit Schellenberger and Thomas Reiprich from the University of Bonn in Germany.

    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 12:28 pm on December 12, 2015 Permalink | Reply
    Tags: , , Jellyfish nebula, NASA Chandra   

    From Chandra- “IC 443: What Spawned the Jellyfish Nebula?” 

    NASA Chandra

    1
    Wide Field Optical: Focal Pointe Observatory/B.Franke, Inset: X-ray: NASA/CXC/MSFC/D.Swartz et al, Inset: Optical: DSS, SARA
    Release Date December 10, 2015

    The Jellyfish Nebula (officially known as IC 443) is a supernova remnant about 5,000 light years from Earth.

    Astronomers have been looking for the spinning neutron star, or pulsar, from the explosion that created the remnant.

    New Chandra observations have likely spotted a pulsar on the southern edge the Jellyfish Nebula.

    The X-ray data also provide new details about the structure and properties of this pulsar.

    The Jellyfish Nebula, also known by its official name IC 443, is the remnant of a supernova lying 5,000 light years from Earth. New Chandra observations show that the explosion that created the Jellyfish Nebula may have also formed a peculiar object located on the southern edge of the remnant, called CXOU J061705.3+222127 or J0617 for short. The object is likely a rapidly spinning neutron star, or pulsar.

    When a massive star runs out of thermonuclear fuel, it implodes, forming a dense stellar core called a neutron star. The outer layers of the star collapse toward the neutron star then bounce outward in a supernova explosion. A spinning neutron star that produces a beam of radiation is called a pulsar. The radiation sweeps by like a beacon of light from a lighthouse and can be detected as pulses of radio waves and other types of radiation.

    This new composite image includes a wide-field view from an astrophotographer that shows the spectacular filamentary structure of IC 443. Within the inset box, another optical image from the [ESO] Digitized Sky Survey (red, green, orange, and cyan) has been combined with X-ray data from Chandra (blue). The inset shows a close-up view of the region around J0617.

    The Chandra image reveals a small, circular structure (or ring) surrounding the pulsar and a jet-like feature pointing roughly in an up-down direction that passes through the pulsar. It is unclear if the long, pink wisp of optical emission is related to the pulsar, as similar wisps found in IC 443 are unrelated to X-ray features from the pulsar. The ring may show a region where a high speed wind of particles flowing away from the pulsar, is slowing down abruptly. Alternately, the ring may represent a shock wave, similar to a sonic boom, ahead of the pulsar wind. The jet could be particles that are being fired away from the pulsar in a narrow beam at high speed.

    The X-ray brightness of J0617 and its X-ray spectrum, or the amount of X-rays at different wavelengths, are consistent with the profiles from known pulsars. The spectrum and shape of the diffuse, or spread out, X-ray emission surrounding J0617 and extending well beyond the ring also match with expectations for a wind flowing from a pulsar.

    2
    X-ray close-up

    The comet-like shape of the diffuse X-ray emission suggests motion towards the lower right of the image. As pointed out in previous studies, this orientation is about 50 degrees away from the direction expected if the pulsar was moving away from the center of the supernova remnant in a straight line. This misalignment has cast some doubt on the association of the pulsar with the supernova remnant. However, this misalignment could also be explained by movement towards the left of material in the supernova remnant pushing J0617’s cometary tail aside.

    This latest research points to an estimate for the age of the supernova remnant to be tens of thousands of years. This agrees with previous work that pegged IC 443’s age to be about 30,000 years. However, other scientists have inferred much younger ages of about 3,000 years for this supernova remnant, so its true age remains in question.

    These findings are available in a paper published in The Astrophysical Journal and is available online. The authors are Douglas Swartz (Marshall Space Flight Center), George Pavlov (Penn State University), Tracy Clarke (Naval Research Laboratory), Gabriela Castelletti (IAEF, Argentina), Vyacheslav Zavlin (MSFC), Niccolo Bucciantini (INAF, Italy), Margarita Karovska (Smithsonian Astrophysical Observatory), Alexander van der Horst (George Washington University), Mihoko Yukita (Goddard Space Flight Center), and Martin Weisskopf (MSFC).

    Another view:
    3
    No image credit

    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.

     
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