AAS 195th Meeting, January 2000
Session 16. Blazar and Quasar Variability
Display, Wednesday, January 12, 2000, 9:20am-6:30pm, Grand Hall

## [16.03] The Deep X-ray Radio Blazar Survey (DXRBS)

P. Padovani (ESA, STScI), H. Landt (STScI), E. Perlman (STScI), P. Giommi (BeppoSAX SDC)

We give an update on the status of the Deep X-ray Radio Blazar Survey (DXRBS). The DXRBS candidate list is obtained by correlating the ROSAT WGACAT database with several radio catalogs and restricting the selection to flat spectrum radio sources (\alphar \le 0.70). The selection criteria result in a very high efficiency (~90%) at finding blazars, that is flat-spectrum radio quasars (FSRQ) and BL Lacertae objects. DXRBS will provide a sample of about 350 blazars, selected in an homogeneous way and reaching X-ray and radio fluxes about 10 -- 20 times deeper than currently available, complete blazar samples. Identification of the sources is ~85% complete. We present here some DXRBS results as of December 1999, namely: a breakdown of the source classification; the redshift and luminosity distribution for FSRQ and BL Lacs; the number counts for both classes, which for the first time reach relatively faint flux levels (~50 mJy and ~2 \times 10-14 c.g.s. for the radio and X-ray band respectively); and an estimate of the evolutionary properties of DXRBS blazars.