[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.