Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 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
    Signatur Availability
    BibTip Others were also interested in ...
  • 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
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2015-10-23
    Description: Tidal forces close to massive black holes can violently disrupt stars that make a close approach. These extreme events are discovered via bright X-ray and optical/ultraviolet flares in galactic centres. Prior studies based on modelling decaying flux trends have been able to estimate broad properties, such as the mass accretion rate. Here we report the detection of flows of hot, ionized gas in high-resolution X-ray spectra of a nearby tidal disruption event, ASASSN-14li in the galaxy PGC 043234. Variability within the absorption-dominated spectra indicates that the gas is relatively close to the black hole. Narrow linewidths indicate that the gas does not stretch over a large range of radii, giving a low volume filling factor. Modest outflow speeds of a few hundred kilometres per second are observed; these are below the escape speed from the radius set by variability. The gas flow is consistent with a rotating wind from the inner, super-Eddington region of a nascent accretion disk, or with a filament of disrupted stellar gas near to the apocentre of an elliptical orbit. Flows of this sort are predicted by fundamental analytical theory and more recent numerical simulations.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Miller, Jon M -- Kaastra, Jelle S -- Miller, M Coleman -- Reynolds, Mark T -- Brown, Gregory -- Cenko, S Bradley -- Drake, Jeremy J -- Gezari, Suvi -- Guillochon, James -- Gultekin, Kayhan -- Irwin, Jimmy -- Levan, Andrew -- Maitra, Dipankar -- Maksym, W Peter -- Mushotzky, Richard -- O'Brien, Paul -- Paerels, Frits -- de Plaa, Jelle -- Ramirez-Ruiz, Enrico -- Strohmayer, Tod -- Tanvir, Nial -- England -- Nature. 2015 Oct 22;526(7574):542-5. doi: 10.1038/nature15708.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Astronomy, The University of Michigan, 1085 South University Avenue, Ann Arbor, Michigan 48103, USA. ; SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands. ; Department of Physics and Astronomy, Universiteit Utrecht, PO Box 80000, 3508 TA Utrecht, The Netherlands. ; Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands. ; Department of Astronomy, The University of Maryland, College Park, Maryland 20742, USA. ; Department of Physics, University of Warwick, Coventry CV4 7AL, UK. ; Joint Space-Science Institute, University of Maryland, College Park, Maryland 02742, USA. ; Astrophysics Science Division, NASA Goddard Space Flight Center, MC 661, Greenbelt, Maryland 20771, USA. ; Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, Massachusetts 02138, USA. ; The Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, USA. ; Department of Physics and Astronomy, University of Alabama, PO Box 870324, Tuscaloosa, Alabama 35487, USA. ; Department of Physics and Astronomy, Wheaton College, Norton, Massachusetts 02766, USA. ; Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK. ; Columbia Astrophysics Laboratory and Department of Astronomy, Columbia University, 550 West 120th Street, New York, New York 10027, USA. ; Department of Astronomy and Astrophysics, University of California, Santa Cruz, California 95064, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26490619" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...