The Hierarchical Module For The Co-evolution Of SMBHs And DM Halos

In this thesis we build up the growth and co-evolution of MBHs and the DM halo over the cosmic time under the hierarchical structure formation scenario in a ACDM cosmology. We use a similar algorithm as described in [1,2]. The merger history (from z=20to present) of220present-day halos with masses1011M<M<1015M is created based on the extended Press-Schechter formalism. At high redshift, seed BHs in the prototype galaxies formed as a result of the collapse of Pop III stars. When halos merge, they follow the merger tree of halos, migrate into the galaxy centers by the dynamical friction, and then begin to accrete gas after each major merger. MBHs continue accreting the surrounding gas till they set on the MBH-σ*relation. Since most galaxies contain BHs at their center, it is natural to form a MBH binary as the satellite galaxy merges with a larger one. In order to check whether our simulations are consistent with the observations, we compare the QLF of the active BHs and the mass density of all MBHs from simulations with the observations.Having taken two different accretion models into consideration, we track the co-evolution of massive black holes (MBH) and dark matter (DM) halos, espe-cially, the corresponding coalescence rates of MBHs in a hierarchical structure formation scenario. To fit the observations of AGN luminosity function, we use the results from fully relativistic magnetohydrodynamic (MHD) accretion simula-tions and consider a prolonged MHD disk model. In all simulations, seed BHs are assumed to be the end products of the Pop III stars. The prolonged-MHD model and the Chaotic Model produced better matches with the observed quasar lumi-nosity function(QLF). We compute and compare the coalescence rates of MBH binaries from those different models. The coalescence rates are distinguishable in the different mass intervals among the models but with the same total coalescence rate (～48per unit observed year), and the total count is less than-70-120per unit observed year predicted by [3] and [4].We present mass ratio distributions of massive black hole (MBH) binaries with circum-binary disks at different evolution stages in the hierarchical models for the co-evolution of MBHs and their halos. The mass ratio distribution of the MBH binaries at the final coalescence stage is modified to has more equal-mass binaries. We compared the theoretical results to the observed mass ratio distribution of the MBHs in merging pair galaxies. The theoretical mass ratio distribution of the far separated MBH binaries, which are before the interaction with the circumdisk, is consistent with the observation. The presence of the circum-binary disk will equalize the masses of the MBH binaries. Compared to the MBH binaries in merging galaxies, we predict a different mass ratio distribution that has more close MBH binaries of equal mass after the interaction of MBHs with a circum-disk.Based on the simulations, it is worth understanding better the potential ca-pability of ALIA to detect light seed black holes beyond those of LISA and the corresponding event rates. Even the detection of a single event of a light seed black hole will be of significant astrophysical importance for the understanding of the hierarchical assembling process, the life cycle and destination of first stars and gas dynamics in the earliest galaxies.The cosmological parameters adopted in the simulations are as follows: ΩM=0.3,ΩA=0.7, h=0.7,Ωbh2=0.02, σ8=0.93and n=1. Here h is defined by Ho=h×100km s-1Mpc-1.