Special relativistic e ects on the strength of the uorescentK iron line from black hole accretion disks

Special relativistic eeects on the strength of the uorescent K iron line from black hole accretion disks. ABSTRACT The broad iron K emission line, commonly seen in the X-ray spectrum of Seyfert nuclei, is thought to originate when the inner accretion disk is illuminated by an active disk-corona. We show that relative motion between the disk and the X-ray emitting material can have an important innuence on the observed equivalent width (EW) of this line via special relativistic aberration and Doppler eeects. We suggest this may be relevant to understanding why the observed EW often exceeds the prediction of the standard X-ray reeection model. Several observational tests are suggested that could disentangle these special relativistic eeects from iron abundance eeects.