2014/10/30 by Sherman, Sydney, Sun, Mouyuan, Zhu, Qirong +2
#Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences
paper · doi:10.48550/arxiv.1410.8514
Observations have shown that supermassive black holes in nearby elliptical galaxies correlate tightly with the stellar velocity dispersion (the \MBH - σ relation) and the stellar mass (the \MBH - \Mhost relation) of their host spheroids. However, the origin of these correlations remains ambiguous. In a previous paper by Zhu et al., we proposed a model which links the M-σ relation to the the dynamical state of the system and the \MBH - \Mhost relation to the self-regulation of galaxy growth. To test this model, we compile a sample of observed galaxies with different properties and examine the dependence of the above correlations on these parameters. We find that galaxies that satisfy the the \MBH - σ correlation appear to have reached virial equilibrium, as indicated by the ratio between kinetic energy and gravitational potential, 2K/U ∼ 1. Furthermore, the ratio of black hole accretion rate to star formation rate remains nearly constant, BHAR /SFR ∼ 10-3, in active galaxies over a wide range of mass in the redshift range z=0 - 3. These results confirm our theoretical model that the observed correlations have different origins: the \MBH - σ relation may result from galaxy relaxation, while the \MBH - \Mhost relation may be due to self-regulated black hole accretion and star formation in galaxies.