The discovery of an X-ray selected, radio-loud quasar at z = 3. 9

Journal Article · Sat Aug 01 04:00:00 EDT 1992 · Astronomical Journal; (United States)

DOI:https://doi.org/10.1086/116251· OSTI ID:7159137

Becker, R H; Helfand, D J; White, R L ^[1]

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1. California, University, Davis (United States) Lawrence Livermore National Laboratory, Livermore, CA (United States) Columbia University, NY (United States) Joint Institute for Laboratory Astrophysics, Boulder, CO (United States) Space Telescope Science Institute, Baltimore, MD (United States)

About 600 weak X-ray sources from a data base of about 100,000 2-4sigma fluctuations derived from Einstein Observatory imaging proportional counter X-ray images are selected on the basis of a flux-limited catalog of radio sources in the northern sky. Optical spectroscopy of only six of these sources resulted in the discovery of a quasar with an emission-line redshift of 3.87. Subsequent VLA observations reveal the source to have a flat-spectrum radio core plus an unresolved radio lobe 2.5 arcsec away with a spectral index of 1.45. The lobe is connected to the core by a weak jet. The integrated flux density of the source at 20 cm is 0.66 Jy. The v magnitude of the quasar is 19.5, and the tentative X-ray sources has a very soft spectrum. The properties of this object are discussed in the context of known high-redshift radio sources and existing X-ray selected quasar samples, and the potential of the present discovery technique for examining the properties of very distant active galaxies is explored. 20 refs.

• OSTI ID: 7159137
• Journal Information: Astronomical Journal; (United States), Journal Name: Astronomical Journal; (United States) Vol. 104:2; ISSN ANJOAA; ISSN 0004-6256
• Country of Publication: United States
• Language: English

Related Subjects

661300* -- Other Aspects of Physical Science-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC RADIO SOURCES
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
FLUX DENSITY
GALAXIES
IONIZING RADIATIONS
MEASURING INSTRUMENTS
MORPHOLOGY
PLASMA JETS
PROPORTIONAL COUNTERS
QUASARS
RADIATION DETECTORS
RADIATIONS
RED SHIFT
SPECTRA
VISIBLE SPECTRA
X RADIATION