Measuring the Fraction of Obscured Quasars by the Infrared Luminosity of Unobscured Quasars

Understand

Recent work has suggested that the fraction of obscured AGN declines with increasing luminosity, but it has been difficult to quantify this trend.

• Here, we attempt to measure this fraction as a function of luminosity by studying the ratio of mid-infrared to intrinsic nuclear bolometric luminosity in unobscured AGN.
• Because the mid-infrared is created by dust reprocessing of shorter wavelength nuclear light, this ratio is a diagnostic of f_obsc, the fraction of solid angle around the nucleus covered by obscuring matter.
• In order to eliminate possible redshift-dependences while also achieving a large dynamic range in luminosity, we have collected archival 24 micron MIPS photometry from objects with z~1 in the Sloan Digital Sky Survey (SDSS), the Great Observatories Origins Deep Survey (GOODS) and the Cosmic Evolution Survey (COSMOS).