Abstract Details
Name: Dipanweeta Bhattacharyya Affiliation: Indian Institute of Astrophysics, Bangalore Conference ID: ASI2017_552 Title : Evolution of the black hole nuclei in elliptical galaxies Authors and Co-Authors : A. Mangalam, Indian Institute of Astrophysics Abstract Type : Poster Abstract Category : Extragalactic astronomy Abstract : The $M_{\bullet} \propto \sigma^{p}$ relation is likely the result of a complicated nexus between the stellar and gas dynamics within the radius of influence, and the galaxy formation physics that determines the mass of the seed black hole. We consider the relativistic effects on the loss cone for isotropic distribution functions (DFs) and show that the stellar loss cone fueling gives a trend $M_\bullet \propto \sigma^5$ whereas the gas feed back regulation by momentum driven flow yields $M_\bullet \propto \sigma^4$. To investigate this question further, we consider realistic elliptical galaxies with spherical intensity profiles and invert it to calculate the density and the DF, $f(E)$, of the stars in presence of the supermassive black hole (SMBH) at the center. Employing the DF we compute the line of sight velocity dispersion while assuming a proportionality relation, $M_b =f M_{\bullet}$; applying this to several ellipticals we find the best fit global $p$ and $f$. For the Nuker profile, we conclude that the $p$ and $f$ values thus derived are consistent with the observed range; this provides clues to the galaxy formation physics. We also implement the same procedure for the anisotropic case using the Osipkov-Merritt DF and show that the derived index $p$ is lesser than the observed value. We also model a more generalized axisymmetric distribution function $f(E, L_z)$ and obtain useful physical constraints on the SMBH nuclei. Using the results of our models, we calculate the evolution of the $M_{\bullet} - \sigma$ relation over cosmic time. |