科研之友
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摘要
We have examined the effect of slow growth of a central black hole on spherical galaxies that obey Sersic or R-1/m surface-brightness profiles. During such growth the actions of each stellar orbit are conserved, which allows us to compute the final distribution DF) if we assume that the initial DF is isotropic. We find that black hole growth leads to a central cusp or "excess light," in which the surface brightness varies with radius as R-1.3 (with a weak dependence on Sersic index m), the line-of-sight velocity dispersion varies as R-1/2, and the velocity anisotropy is beta similar or equal to -0.24 to -0.28 depending on m. The excess stellar mass in the cusp scales approximately linearly with the black hole mass, and is typically 0.5-0.85 times the black hole mass. This process may strongly influence the structure of nuclear star clusters in spheroidal galaxies if they contain black holes.
- 出版日期2016-5
