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  • 1
    Publication Date: 2014-03-07
    Description: The co-evolution of a supermassive black hole with its host galaxy through cosmic time is encoded in its spin. At z 〉 2, supermassive black holes are thought to grow mostly by merger-driven accretion leading to high spin. It is not known, however, whether below z approximately 1 these black holes continue to grow by coherent accretion or in a chaotic manner, though clear differences are predicted in their spin evolution. An established method of measuring the spin of black holes is through the study of relativistic reflection features from the inner accretion disk. Owing to their greater distances from Earth, there has hitherto been no significant detection of relativistic reflection features in a moderate-redshift quasar. Here we report an analysis of archival X-ray data together with a deep observation of a gravitationally lensed quasar at z = 0.658. The emission originates within three or fewer gravitational radii from the black hole, implying a spin parameter (a measure of how fast the black hole is rotating) of a = 0.87(+0.08)(-0.15) at the 3sigma confidence level and a 〉 0.66 at the 5sigma level. The high spin found here is indicative of growth by coherent accretion for this black hole, and suggests that black-hole growth at 0.5 〈/= z 〈/= 1 occurs principally by coherent rather than chaotic accretion episodes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Reis, R C -- Reynolds, M T -- Miller, J M -- Walton, D J -- England -- Nature. 2014 Mar 13;507(7491):207-9. doi: 10.1038/nature13031. Epub 2014 Mar 5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Astronomy, University of Michigan, Ann Arbor, Michigan 48109, USA. ; Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, California 91125, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24598545" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 2
    Publication Date: 2014-10-10
    Description: The majority of ultraluminous X-ray sources are point sources that are spatially offset from the nuclei of nearby galaxies and whose X-ray luminosities exceed the theoretical maximum for spherical infall (the Eddington limit) onto stellar-mass black holes. Their X-ray luminosities in the 0.5-10 kiloelectronvolt energy band range from 10(39) to 10(41) ergs per second. Because higher masses imply less extreme ratios of the luminosity to the isotropic Eddington limit, theoretical models have focused on black hole rather than neutron star systems. The most challenging sources to explain are those at the luminous end of the range (more than 10(40) ergs per second), which require black hole masses of 50-100 times the solar value or significant departures from the standard thin disk accretion that powers bright Galactic X-ray binaries, or both. Here we report broadband X-ray observations of the nuclear region of the galaxy M82 that reveal pulsations with an average period of 1.37 seconds and a 2.5-day sinusoidal modulation. The pulsations result from the rotation of a magnetized neutron star, and the modulation arises from its binary orbit. The pulsed flux alone corresponds to an X-ray luminosity in the 3-30 kiloelectronvolt range of 4.9 x 10(39) ergs per second. The pulsating source is spatially coincident with a variable source that can reach an X-ray luminosity in the 0.3-10 kiloelectronvolt range of 1.8 x 10(40) ergs per second. This association implies a luminosity of about 100 times the Eddington limit for a 1.4-solar-mass object, or more than ten times brighter than any known accreting pulsar. This implies that neutron stars may not be rare in the ultraluminous X-ray population, and it challenges physical models for the accretion of matter onto magnetized compact objects.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bachetti, M -- Harrison, F A -- Walton, D J -- Grefenstette, B W -- Chakrabarty, D -- Furst, F -- Barret, D -- Beloborodov, A -- Boggs, S E -- Christensen, F E -- Craig, W W -- Fabian, A C -- Hailey, C J -- Hornschemeier, A -- Kaspi, V -- Kulkarni, S R -- Maccarone, T -- Miller, J M -- Rana, V -- Stern, D -- Tendulkar, S P -- Tomsick, J -- Webb, N A -- Zhang, W W -- England -- Nature. 2014 Oct 9;514(7521):202-4. doi: 10.1038/nature13791.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Universite de Toulouse, UPS-OMP, Institut de Recherche en Astrophysique et Planetologie, 9, Avenue du Colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France [2] CNRS, Institut de Recherche en Astrophysique et Planetologie, 9, Avenue du Colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France. ; Cahill Center for Astrophysics, 1216 East California Boulevard, California Institute of Technology, Pasadena, California 91125, USA. ; MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA. ; Physics Department, Columbia University, 538 West 120th Street, New York, New York 10027, USA. ; Space Sciences Laboratory, University of California, Berkeley, California 94720, USA. ; DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby, Denmark. ; Lawrence Livermore National Laboratory, Livermore, California 94550, USA. ; Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK. ; Columbia Astrophysics Laboratory, Columbia University, New York, New York 10027, USA. ; NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA. ; Department of Physics, McGill University, Montreal, Quebec H3A 2T8, Canada. ; Department of Physics, Texas Tech University, Lubbock, Texas 79409, USA. ; Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, Michigan 48109-1042, USA. ; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25297433" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 3
    Publication Date: 2012-08-04
    Description: Supermassive black holes (SMBHs; mass is greater than or approximately 10(5) times that of the Sun) are known to exist at the center of most galaxies with sufficient stellar mass. In the local universe, it is possible to infer their properties from the surrounding stars or gas. However, at high redshifts we require active, continuous accretion to infer the presence of the SMBHs, which often comes in the form of long-term accretion in active galactic nuclei. SMBHs can also capture and tidally disrupt stars orbiting nearby, resulting in bright flares from otherwise quiescent black holes. Here, we report on a ~200-second x-ray quasi-periodicity around a previously dormant SMBH located in the center of a galaxy at redshift z = 0.3534. This result may open the possibility of probing general relativity beyond our local universe.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Reis, R C -- Miller, J M -- Reynolds, M T -- Gultekin, K -- Maitra, D -- King, A L -- Strohmayer, T E -- New York, N.Y. -- Science. 2012 Aug 24;337(6097):949-51. doi: 10.1126/science.1223940. Epub 2012 Aug 2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA. rdosreis@umich.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22859817" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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