Discovery of an X-Ray Selected Optically Highly Variable Quasar
Tagliaferri, G.; Branduardi-Raymont, G.; Giommi, P.; Mason, K. O.; Angelini, L.; Murdin, P. G.; Allington-Smith, J. R.; Mittaz, J. P. D.
United Kingdom, Netherlands
Abstract
In the course of a programme of optical identification of serendipitous EXOSAT sources we have discovered a quasar (EX0033041-2613.1, referred to here as Gepu; z = 0.67) which varied by more than 3 magnitudes between November 1985 and February 1988. We present the results of optical spectroscopy and CCD photometry of the quasar which were obtained during 1988. We complement the recent data with historical observations (both photometric and spectroscopic) in order to investigate the long term behaviour of this object. It is hard to make a classification of Gepu with the limited data available, and further optical monitoring is planned.