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The First Observations of the Second Brightest Quasar

K. M. Leighly·J. P. Halpern·D. J. Helfand·R. H. Becker·C. D. Impey
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Abstract

We report the discovery of a new bright quasar PHL 1811 as part of a followup program to identify bright quasars in the FIRST radio survey. With B=13.9, R=13.9, and z=0.192, this quasar is now the second brightest quasar (in apparent magnitude) known beyond z=0.1. Optically classified as a Narrow-line Seyfert 1 galaxy (NLS1), PHL 1811 is unusual for an object in this class in that it was not detected in X-rays in the ROSAT All Sky survey or in any previous X-ray survey. A follow-up BeppoSAX observation confirms that it is deficient in X-rays compared with other quasars, but poor signal to noise prevents a definitive characterization of the X-ray spectrum. We consider three alternative hypotheses to explain why PHL 1811 is a weak X-ray source: 1.) it is a BALQSO and suffers X-ray absorption; 2.) like several other luminous NLS1s, it exhibits high amplitude X-ray variability, and has been observed only when it is in an X-ray quiescent state; 3.) it is intrinsically weak because it simply lacks an X-ray emitting region.

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K. M. Leighly, J. P. Halpern, D. J. Helfand, R. H. Becker, C. D. Impey. 2001-03-01. The First Observations of the Second Brightest Quasar. https://doi.org/10.1086/321094

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