ASCA Observation of a Radio-Loud Quasar and a New Candida
te for a Cluster of Galaxies
Fumie Akimoto, A. Furuzawa, Y. Tawara, Y. Kamata and K. Yamashita
Abstract
During an X-ray observation of the distant galaxy cluster CL 0107+31 (z
= 0.69) with ASCA, an extended X-ray source was detected in the field of
view. Based on an image analysis in two different energy bands of 1-3
keV and 3-10 keV, we found that this source consists of a hard
point-like component and an additional soft diffuse X-ray source
extended over >= 3' in radius. However, due to poor photon
statistics, we could not distinguish whether their X-ray spectra are
thermal or non-thermal. The peak position of the central X-ray source
coincides with a radio-loud quasar, NRAO 58. NRAO 58 is found to have a
power-law spectrum with a photon index 1.6+0.3-0.2
and a (2-10 keV) luminosity of ~ 4*E46 erg s-1
(in the quasar rest frame). The extended component is likely to be a
candidate for a nearby galaxy group which accidentally coincides with
the quasar.