The Care and Growth of Super Massive Black Holes
Andreea Petric
University of Hawaii / Institute for Astronomy / Canada-France-Hawaii Telescope



Observations of the dynamics of stars and gas in the nuclear regions of nearby galaxies suggest that the overwhelming majority of spheroidal galaxies in the local Universe contain massive black-holes (BH) and that, with some important caveats, the masses of those central BH correlate with the velocity dispersion of the stars in the spheroid and the bulge luminosities. Much research has been dedicated to understanding the mechanisms responsible for such a fundamental - perhaps causal - relation. An accurate census of the basic properties of the cold interstellar medium (ISM) in galaxies with accreting super-massive black holes at their centers, i.e. galaxies that host active galactic nuclei (AGN), is pertinent to those investigations because cold molecular gas fuels both black hole growth and star-formation. We present highly sensitivity observations taken with the Herschel Space Observatory to estimate the cold ISM content in a sample of ~200 nearby (z <= 0.5), optically luminous QSOs. The cold ISM properties of these luminous AGN are discussed in the context of models that envision that quasar activity is triggered by gas-rich galaxy mergers. We also present infrared spectroscopic and photometric observations of a sample of ~200 nearby (z <= 0.1) Luminous Infrared Galaxies (LIRGs). Luminous Infrared Galaxies (LIRGs) make stars and grow super-massive black holes (SMBH) at a faster rate than most of their local counterparts. Their number density increase with redshift until z~1 when they dominate galaxy evolution. Some are mergers, some are not, some are feeding the central SMBH, others may not be. Because of this, LIRGS constitute a perfect laboratory to observe and study how galaxies grow and to test the conditions in which gas rich mergers trigger episodes of growth for the central SMBH and the host galaxy.