Optical, near-infrared and hard X-ray observations of SAXJ1353.9+1820: a red quasar

We present the results of a follow-up ASCA observation and multicolour opti cal and near-infrared photometry carried out at the 3.5-m Italian National Telescope Galileo of SAX J1353.9+1820. This object, serendipitously discove red by BeppoSAX in the 5-10 keV 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 (similar to 10(4 4) erg s(-1)) obscured by a column density of the order of 10(22) cm(-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 ba ckground are briefly outlined.