BEAMED X-RAYS IN RADIO-LOUD QUASARS

The X-ray spectra of radio-loud quasars are considerably steeper in th e ROSAT PSPC band (0.1-2.4 keV) than in the slightly harder Einstein I PC band (0.3-3.5 keV). In order to explain this fact Jackson et al. (1 993) simulated PSPC and IPC observations of a beaming model spectrum ( Browne & Murphy 1987) plus a soft power law component. Whereas they su cceeded to reproduce the observed steep ROSAT spectra, their simulated Einstein spectra were too steep. They therefore concluded that the co ncept of the beaming model might be wrong. With the help of a PSPC obs ervation of 3C273 we show that the assumed shape of the soft component could be the origin of this failure.