Black-hole masses of type?1 AGN in the XMM-Newton bright serendipitous survey

摘要

Aims. We derive masses of the central supermassive black hole (SMBH) and accretion rates for 154 type?1 AGN belonging to a well-defined X-ray-selected sample, the XMM-Newton serendipitous sample (XBS). Methods. We used the most recent “single-epoch” relations, based on Hβ and MgIIλ2798?? emission lines, to derive the SMBH masses. We then used the bolometric luminosities, computed on the basis of an SED-fitting procedure, to calculate the accretion rates, both absolute and normalized to the Eddington luminosity (Eddington ratio). Results. The selected AGNs cover a range of masses from 107 to 1010 M⊙ with a peak around 8?×?108 M⊙ and a range of accretion rates from 0.01 to ~50?M⊙/year (assuming an efficiency of 0.1), with a peak at ~1?M⊙/year. The values of Eddington ratio range from 0.001 to ~0.5 and peak at 0.1.