TY - JOUR
T1 - The extreme X-ray luminosity of the z = 4.72 radio-loud quasar GB 1428+4217
AU - Fabian, A. C.
AU - Brandt, W. N.
AU - McMahon, R. G.
AU - Hook, I. M.
PY - 1997
Y1 - 1997
N2 - We report on a ROSAT High Resolution Imager observation of the radio-loud quasar GB 1428+4217, which is at a redshift z = 4.72. The quasar was well detected, with a flux in the observed 0.1-2.4 keV band of ∼10-12 erg cm-2 s-1. Our result confirms that the object in the catalogue of serendipitous X-ray sources, WGACAT, is indeed the quasar. GB 1428+4217 is therefore the brightest X-ray source above a redshift of 4 and has an extremely high isotropic X-ray luminosity, which exceeds that in other (observed) bands. The observed spectral energy distribution of the object therefore peaks at X-ray, or even shorter, wavelengths. We speculate that the emission in the object is beamed toward us.
AB - We report on a ROSAT High Resolution Imager observation of the radio-loud quasar GB 1428+4217, which is at a redshift z = 4.72. The quasar was well detected, with a flux in the observed 0.1-2.4 keV band of ∼10-12 erg cm-2 s-1. Our result confirms that the object in the catalogue of serendipitous X-ray sources, WGACAT, is indeed the quasar. GB 1428+4217 is therefore the brightest X-ray source above a redshift of 4 and has an extremely high isotropic X-ray luminosity, which exceeds that in other (observed) bands. The observed spectral energy distribution of the object therefore peaks at X-ray, or even shorter, wavelengths. We speculate that the emission in the object is beamed toward us.
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U2 - 10.1093/mnras/291.1.l5
DO - 10.1093/mnras/291.1.l5
M3 - Article
AN - SCOPUS:0008574209
SN - 0035-8711
VL - 291
SP - L5-L7
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 1
ER -