First observations of the second-brightest quasar

We report the discovery of a new bright quasar, PHL 1811, as part of a foll ow-up 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 qu asar (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 Surv ey or in any previous X-ray survey. A follow-up BeppoSAX observation confir ms that it is deficient in X-rays compared with other quasars, but poor sig nal-to-noise ratio prevents a definitive characterization of the X-ray spec trum. We consider three alternative hypotheses to explain why PHL 1811 is a weak X-ray source: (1) it is a broad absorption line quasi-stellar object and suffers X-ray absorption; (2) like several other luminous NLS1s, it exh ibits high-amplitude X-ray variability and has been observed only when it i s in an X-ray-quiescent state; and (3) it is intrinsically weak because it simply lacks an X-ray-emitting region.