Heng HAO
(Harvard University, USA)
COSMOS enables a qualitatively new study of of the Spectra Energy Distributions (SEDs) of AGNs. We present a study of the SEDs of 324 X-ray (XMM) selected Type~1 AGNs using the 40-plus photometry points from COSMOS. The SEDs are corrected for broad emission line contributions, for Galactic extinction, and use two methods to correct for variability. We present the mean SED and the dispersion of SEDs,and show examples of the wide range of SEDs encountered. Reddening and host galaxy contamination of a standard 'Elvis et al. 1994' SED can account for a large fraction of the observed SED variety. We show how the Hubble images, and an iterative fitting method can estimate host galaxy types and deviations from the Elvis et al. continuum.
Not all the SEDs can be explained simply by reddening and host contribution. We present preliminary evidence for evolution of the SED shape with redshift. We also examine the correlation of the SED shape with respect to physical parameters: black hole mass and accretion rate.