M–sigma relation

The M–sigma (or M–σ) relation is an empirical correlation between the stellar velocity dispersion σ of a galaxy bulge and the mass M of the supermassive black hole at its center. The M–σ relation was first presented in 1999 during a conference at the Institut d'Astrophysique de Paris in France by David Merritt. Merritt's proposed form of the relation, which he called the "Faber–Jackson law for black holes", was M 10 8 M ⊙ ≈ 3.1 ( σ 200 k m s − 1 ) 4 . {\displaystyle {\frac {M}{10^{8}M_{\odot }}}\approx 3.1\left({\frac {\sigma }{200~{\rm {km}}~{\rm {s}}^{-1}}}\right)^{4}.} where M ⊙ {\displaystyle M_{\odot }} is the solar mass. Publication of the relation in a refereed journal, by two groups, took place the following year. One of many recent studies, based on the growing sample of published black hole masses in nearby galaxies, gives M 10 8 M ⊙ ≈ 1.9 ( σ 200 k m