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  • 1
    Publication Date: 2014-08-19
    Description: M82 X-1, the brightest X-ray source in the galaxy M82, has been thought to be an intermediate-mass black hole (100 to 10,000 solar masses) because of its extremely high luminosity and variability characteristics, although some models suggest that its mass may be only about 20 solar masses. The previous mass estimates were based on scaling relations that use low-frequency characteristic timescales which have large intrinsic uncertainties. For stellar-mass black holes, we know that the high-frequency quasi-periodic oscillations (100-450 hertz) in the X-ray emission that occur in a 3:2 frequency ratio are stable and scale in frequency inversely with black hole mass with a reasonably small dispersion. The discovery of such stable oscillations thus potentially offers an alternative and less ambiguous means of mass determination for intermediate-mass black holes, but has hitherto not been realized. Here we report stable, twin-peak (3:2 frequency ratio) X-ray quasi-periodic oscillations from M82 X-1 at frequencies of 3.32 +/- 0.06 hertz and 5.07 +/- 0.06 hertz. Assuming that we can extrapolate the inverse-mass scaling that holds for stellar-mass black holes, we estimate the black hole mass of M82 X-1 to be 428 +/- 105 solar masses. In addition, we can estimate the mass using the relativistic precession model, from which we get a value of 415 +/- 63 solar masses.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pasham, Dheeraj R -- Strohmayer, Tod E -- Mushotzky, Richard F -- England -- Nature. 2014 Sep 4;513(7516):74-6. doi: 10.1038/nature13710. Epub 2014 Aug 17.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Astronomy Department, University of Maryland, College Park, Maryland 20742, USA [2] Astrophysics Science Division and Joint Space-Science Institute, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA. ; Astrophysics Science Division and Joint Space-Science Institute, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA. ; Astronomy Department, University of Maryland, College Park, Maryland 20742, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25132552" 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: 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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