I. G. Roseboom, A. Lawrence, M. Elvis, S. Petty, Yue Shen, H. Hao
We investigate the range of covering factors (determined from the ratio of IR to UV/optical luminosity) seen in luminous quasars using a combination of data from the WISE, UKIDSS and SDSS surveys. Accretion disk (UV/optical) and obscuring dust (IR) luminosities are measured via the use of a simple three component SED model. We use these estimates to investigate the distribution of covering factors and its relationship to both accretion luminosity and IR SED shape. The distribution of covering factors (f_C) is observed to be log-normal, with a bias-corrected mean of =-0.48 and standard deviation of 0.19. The fraction of IR luminosity emitted in the near-IR (1--5 micron) is found to be high (~40 per cent), and dependant on covering factor.
View original:
http://arxiv.org/abs/1205.4543
No comments:
Post a Comment