Optical, near-infrared and hard x-ray observations of SAX J1353.9+1820: A red quasar

Abstract

We present the results of a follow-up ASCA observation and multicolour optical and near-infrared photometry carried out at the 3.5-m Italian National Telescope Galileo of SAX J1353.9+1820. This object, serendipitously discovered by BeppoSAX in the 5-10keV band, has been spectroscopically identified as a red quasar at z = 0.217. The combined X-ray and optical-infrared data reveal the presence of a moderately luminous X-ray source (∼1044ergs-1) obscured by a column density of the order of 1022cm-2 in an otherwise optically passive early-type galaxy. The implications for the nature of red quasars and their possible contribution to the hard X-ray background are briefly outlined.