Title: Modeling the Supermassive Black Hole and Host Galaxy Connection Over Cosmic Time
Abstract: Stellar and gas dynamics lead us to believe that a supermassive black hole (SMBH) lurks at the center of every massive galaxy. Their masses correlate with host galaxy properties, suggesting coeval growth. SMBH growth is constrained by luminous accretion out to redshift 6, when the universe was only a Gyr old. Utilizing such multi-wavelength, multi-redshift data, we develop a semi-analytic model (SAM) which links the growth of SMBHs to the properties of their host galaxies. We find that an efficient, galaxy merger-triggered growth mode is sufficient to explain all SMBH assembly to redshift 2. However, at lower redshifts, a second steady mode of SMBH accretion is required to explain the observations. Properly modeling the SMBH-galaxy connection also allows us to reproduce the phenomenon of "downsizing"--more massive SMBHs assembling earlier. Future observatories, such as JWST, Lynx, and LISA, are expected to place further constraints on the physics of SMBH seeding and accretion.
Munich Center for Mathematical Philosophy
TITLE: "A Strengthened Zeroth Law for Black Holes"
The standard formulation of the Zeroth Law of black-hole thermodynamics (constancy of surface gravity) is unsatisfactory from the point of view of traditional thermodynamics, as many of the most fundamental structures and concepts in it are grounded on transitivity of equilibrium, the standard formulation of the Zeroth Law in that context. I propose two notions of equilibrium that may allow for a formulation of the Zeroth Law for black holes directly analogous to the standard formulation. I then sketch a proof based on one of them, approximation constancy of surface gravity and on a formulation of an appropriate analogue of the Kelvin Postulate for black holes. I propose a conjecture based on the second one. I conclude by outlining how the strengthened Zeroth Law supports many of the standard constructions and concepts as in ordinary thermodynamics, with a few remarks about how all of this may bear on the search for an underlying statistical theory grounding black-hole thermodynamics.