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Science 7 January 2005:
Vol. 307. no. 5706, pp. 77 - 80
DOI: 10.1126/science.1105746
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Review

Black Hole Accretion

Ramesh Narayan1* and Eliot Quataert2*

Black holes are most often detected by the radiation produced when they gravitationally pull in surrounding gas, in a process called accretion. The efficiency with which the hot gas radiates its thermal energy strongly influences the geometry and dynamics of the accretion flow. Both radiatively efficient thin disks and radiatively inefficient thick disks are observed. When the accreting gas gets close to the central black hole, the radiation it produces becomes sensitive to the spin of the hole and the presence of an event horizon. Analysis of the luminosities and spectra of accreting black holes has yielded tantalizing evidence for both rotating holes and event horizons. Numerical simulations imply that the relativistic jets often seen from accreting black holes may be powered in part by the spin of the hole.

1 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA.
2 Astronomy Department, University of California, 601 Campbell Hall, Berkeley, CA 94720, USA.

* To whom correspondence should be addressed. E-mail: narayan{at}cfa.harvard.edu, eliot{at}astron.berkeley.edu

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THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Disks Around Stars and the Growth of Planetary Systems.
J. S. Greaves (2005)
Science 307, 68-71
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