7 papers
Discovery of Radio-loud Quasars with Redshifts above 4 from the PMN sample
I. M. Hook, R. G. McMahon, P. A. Shaver +1
We present results of a new, large survey for high-redshift radio-loud quasars, which targets quasars with z>4. The survey is based on the PMN and NVSS radio surveys, optically ide…
Variability of the extreme z=4.72 blazar, GB 1428+4217
A. C. Fabian, A. Celotti, G. Pooley +4
We report X-ray and radio variability of GB 1428+4217 which confirm its blazar nature. IR observations reveal a powerful optical-UV component, not obscured by dust, which is sugges…
The ASCA spectrum of the z=4.72 blazar, GB 1428+4217
A. C. Fabian, K. Iwasawa, A. Celotti +3
The X-ray luminous quasar GB 1428+4217 at redshift 4.72 has been observed with ASCA. The observed 0.5-10 keV flux is 3.2E-12 erg/s/cm2. We report here on the intrinsic 4-57 keV X-r…
Discovery of radio-loud quasars with z=4.72 and z=4.01
I. M. Hook, R. G. McMahon
We report the discovery of two radio-loud quasars with redshifts greater than four; GB1428+4217 with z=4.72 and GB1713+2148 with z=4.01. This doubles the number of published radio-…
The FIRST Radio-Loud Broad Absorption Line QSO and Evidence for a Hidden Population of Quasars
Robert H. Becker, Michael D. Gregg, Isobel M. Hook +3
We have discovered two low-ionization broad absorption line quasars in programs to obtain optical spectra for radio-selected quasar candidates from the VLA FIRST Survey (Becker, Wh…
A survey for high-redshift radio-loud quasars: optical spectroscopy of S > 0.2 Jy, flat-spectrum radio sources
I. M. Hook, R. G. McMahon, M. J. Irwin +1
We present optical spectroscopic data for a complete sample of 161 S_5GHz >= 0.2 Jy, flat-spectrum radio sources. The sources were observed as part of a survey for high redshift, r…