The CYDER Survey and the X-Ray Faint Universe

Abstract

The new generation of X-ray Observatories (Chandra and XMM-Newton) has improved the flux limits to which faint X-ray sources can be detected, allowing to resolve most of the X-ray background into discrete sources. Here, we present the Calán-Yale Deep Extragalactic Research (CYDER) Survey. Its scientific goals are broad and include the characterization of the X-ray faint populations surveying Chandra deep fields. Here we present the results on the first Chandra fields studied. We find that the redshift distribution is consistent with that found in the Chandra Deep Field North. The distribution of hardness ratios is, however, softer in our sample. We find a high redshift quasar, CXOCY J125304.0–090737 at z = 4.179, which suggests that the abundance of low luminosity high redshift quasars may be larger than what would be expected from reasonable extrapolations from the quasar optical luminosity function.