[seminar] Astro Journal Club on 25 February

[Oskari Miettinen]

Dear all,

The Astro Journal Club will be held on Wednesday at 10:15 in the seminar
room F-201 of the Physics Department. This time we will discuss about the
dark matter haloes and supermassive black holes.

Presenter: Nikola Baran
Paper title: Connecting Dark Matter Halos with the Galaxy Center and the
Supermassive Black Hole
Authors: Bogdan, A., and Goulding, A. D.

Abstract:
Observational studies of nearby galaxies have demonstrated correlations
between the mass of the central supermassive black holes (BHs) and
properties of the host galaxies, notably the stellar bulge mass or central
stellar velocity dispersion. Motivated by these correlations, the
theoretical paradigm has emerged in which BHs and bulges coevolve.
However, this picture was challenged by observational and theoretical
studies, which hinted that the fundamental connection may be between BHs
and dark matter halos, and not necessarily with their host galaxies. Based
on a study of 3130 elliptical galaxies selected from the Sloan Digital and
ROSAT All Sky Surveys we demonstrate that the central stellar velocity
dispersion exhibits a significantly tighter correlation with the total
gravitating mass, traced by the X-ray luminosity of the hot gas, than with
the stellar mass. This hints that the central stellar velocity dispersion,
and hence the central gravitational potential, may be the fundamental
property of elliptical galaxies that is most tightly connected to the
larger-scale dark matter halo. Furthermore, using the central stellar
velocity dispersion as a surrogate for the BH mass, we find that in
elliptical galaxies the inferred BH mass and inferred total gravitating
mass within the virial radius (or within five effective radii) can be
expressed as MBH \propto M_tot1.6^(+0.6-0.4) (or MBH \propto
M5r_(eff)1.8^(+0.7-0.6)). These results are consistent with a picture in
which the BH mass is directly set by the central stellar velocity
dispersion, which, in turn, is determined by the total gravitating mass of
the system.

Link to the paper: http://adsabs.harvard.edu/abs/2015ApJ...800..124B

Hope to see you all on Wednesday!

Best regards,
Oskari