[AGN, Quasars, Black Holes -- Oral ]
The X-ray AGN Fraction and an AGN/Starformation Sequence from the
Chandra Multiwavelength Project
Paul J Green, SAO/CXC
Daryl Haggard (UWa), Anca Constantin (JMU), Tom Aldcroft (SAO), Scott Anderson (UWa), Dong-Woo Kim (SAO), Wayne Barkhouse (UND)
A fundamental constraint to all theories modeling the interplay
of supermassive black hole accretion and galaxy evolution should be the
the fraction of galaxies in the local universe that host actively
accreting nuclei, yet that number is poorly known. X-ray emission is the
most reliable primary signature of AGN activity. The Chandra Multiwavelength
Project (ChaMP) has carefully analyzed 323 Chandra fields (about 30
square deg) that overlap the SDSS, characterized all optical/X-ray
matches, employed SDSS and our own ChaMP spectroscopy as well as photometric
redshifts. Our detailed volume completeness maps allow us to report here
on the AGN fraction as a function of absolute optical magnitude, X-ray
luminosity, and redshift, from a parent sample of thousands of SDSS
galaxies. We further report on our confirmation with X-rays of a sequence
from starforming to active to passive galaxies that matches trends in
both optical host galaxy characteristics and in large scale environment.