The BH mass of nearby QSOs: the bulge luminosity and virial methods

M. Labita, A. Treves, R. Falomo and M. Uslenghi

We analysed a sample of 31 low z QSOs for which both WFPC2 images and UV FOS spectra are available. For each object, from the magnitude of the host, the CIV line width and the 1350A flux, we estimated the BH mass both through the M(BH)-L(bulge) relation and from the virial method. The comparison of the masses and the distribution of the line widths yield information on the BLR geometry, on the value of the geometrical factor (f=1.3) and on the orientation of QSOs (about 15°-45°).