We report on an XMM-Newton observation of the most distant known quasar, SDSSp J104433.04-012502.2, at z = 5.80. We have detected this quasar with high significance in the rest-frame 3.4-13.6 keV band, making it the most distant cosmic object detected in X-rays; 32 ± 9 counts were collected. SDSSp J104433.04-012502.2 is notably X-ray-weak relative to other luminous, optically selected quasars, with αox = -1.91 ± 0.05 and a 3.4-13.6 keV luminosity of ≈ 1.8 × 1044 ergs s-1. The most likely reason for its X-ray weakness is heavy absorption with NH ≳ 1024 cm-2, as is seen in some broad absorption line quasars and related objects; we discuss this and other possibilities. High-quality spectroscopy from 0.95-1.10 μm to search for blueshifted C IV absorption may elucidate the origin of the X-ray weakness.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science