1201.5888 (Enrico Barausse)

The evolution of massive black holes and their spins in their galactic
hosts    [PDF]

Enrico Barausse

[Abridged] [...] In this paper, we study the mass and spin evolution of
massive black holes within a semianalytical galaxy-formation model that follows
the evolution of dark-matter halos along merger trees, as well as that of the
baryonic components (hot gas, stellar and gaseous bulges, and stellar and
gaseous galactic disks). This allows us to study the mass and spin evolution of
massive black holes in a self-consistent way, by taking into account the effect
of the gas present in galactic nuclei both during the accretion phases and
during mergers. Also, we present predictions, as a function of redshift, for
the fraction of gas-rich black-hole mergers -- in which the spins prior to the
merger are aligned due to the gravito-magnetic torques exerted by the
circumbinary disk -- as opposed to gas-poor mergers, in which the orientation
of the spins before the merger is roughly isotropic. These predictions may be
tested by LISA or similar spaced-based gravitational-wave detectors such as
eLISA/NGO or SGO.

View original: http://arxiv.org/abs/1201.5888