Spitzer Space Telescope - General Observer Proposal #30958


The Duty Cycle of Supermassive Black Holes:  X-raying Virgo

Principal Investigator: Tommaso Treu
           Institution: University of California, Santa Barbara

Co-Investigators: 
Elena Gallo, University of California, Santa Barbara                  
Robert Antonucci, University of California, Santa Barbara             
Jong-Hak Woo, University of California, Santa Barbara                 

Science Category: Galaxy Clusters and Groups 
 Observing Modes: MipsPhot 
  Hours Approved: 9.5 

Abstract:
Nuclear accretion on to super-massive black holes (SMBHs) plays a key
role in the evolution of their host galaxies, as inferred from the
ubiquity of SMBHs and the correlations between BH mass, and host mass
and velocity dispersion.  A fundamental unadressed issue is the actual
distribution of accretion rates;  we propose snapshot observations of
an unbiased sample of 84 early-type galaxies in the Virgo cluster.
Together with joint Spitzer 24 um observations, and publicly available
HST-ACS and UV data, this survey will probe low-level nuclear activity
over four orders of magnitude in black hole mass, thereby delivering
the first unbiased census of the duty cycle of local SMBHs.

This is a CXO Cycle 8 Approved CXO/Spitzer proposal.