Abraham, R. G. | Search NASA

NASA NTRS1996

X-ray QSO evolution from a very deep ROSAT survey

Some 32 quasi-stellar objects (QSOs) were identified to a flux limit of 2 x 10(exp -15) erg/sq cm in the deepest optically identified X-ray survey performed to date. This Rosat position sensitive proportional counter survey (PSPC) is spectroscopically 86 percent complete. The surface density of quasars at this flux limit is 210 +/- 37 per sq deg. The QSO X-ray luminosity function was measured at low luminosities and high redshifts, the highest of which was 3.4.

Jones, L. R.↗

NASA NTRS1992

H0414 + 009 - An X-ray bright BL Lac with a radio tail in a distant cluster of galaxies

Observations of the X-ray-selected BL Lac H0414 + 009 with the VLA indicate a steep-spectrum radio tail extending about 40 arcsec from the core. Deep V, R, and I CCD images show this object to be located in a galaxy whose colors and surface brightness are fitted by an elliptical model. The BL Lac and the cluster of galaxies are physically associated, indicating that BL Lacs do not avoid the cluster environment but are found in groups and clusters as often as are normal radio galaxies; this supports the contention that BL Lacs are normal radio galaxies seen 'end on'.

Mchardy, I. M.↗