AGN from the ROSAT all-sky survey.

This paper presents long slit CCD spectroscopy and X-ray data of 283 AGN detected in the ROSAT-All Sky Survey (RASS). Basis of the sample is the pre-identification of 4651 RASS sources on 134 sky fields (covering in total ~3500sq.deg.). The 283 presented AGN were selected from 1253 AGN candidates resulting from the pre-identification work. The optically brighter counterparts to the ROSAT X-ray sources are favoured. According to the absolute magnitude the sample consists of 158 QSOs and 111 Seyfert 1 galaxies. The remaining 14 objects do not show broad emission lines characterizing Seyfert 1 galaxies. They have to be classified as Seyfert 2 and various types of starburst galaxies. For 143 objects it is possible to derive spectral slopes in the ROSAT X-ray energy range (0.1-2.4keV) from the standard output of the RASS yielding a mean energy index <α_E_>=1.43(f(E){prop.to}E^-α_E_^). For the most common optical emission lines the equivalent width and FWHM were measured.