Astrophysics (Index)About

Salpeter timescale

(Salpeter time)
(timescale for black hole growth)

The Salpeter timescale (or Salpeter time) is a timescale for black hole growth assuming accretion does not exceed the Eddington limit. A growing black hole heats the material it is accreting so it glows, and at some level of accretion, the resulting luminosity's radiation pressure would fully counteract the accretion, resulting in a limit on the possible accretion rate. The timescale is 5×107 years, i.e., the limitation imposed by Eddington luminosity, which suggests a black hole will grow to no more than a factor of e in that many years (i.e., an e-folding time). Of interest is that though this timescale allows plenty of time for the growth of today's most massive supermassive black holes (SMBHs), it leaves insufficient time for such growth of the substantial SMBHs presumed to power observed distant quasars.


(physics,timescale,black holes,limit)
Further reading:
http://academic.sun.ac.za/somerskool/2006/documents/lecture_notes/king/king_lectures.pdf
http://ned.ipac.caltech.edu/level5/Sept13/Shen/Shen1.html
https://ui.adsabs.harvard.edu/abs/1964ApJ...140..796S/abstract
https://kspa.soe.ucsc.edu/sites/default/files/Lecture1_PN.pdf

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