The hidden X-ray Seyfert nucleus in 3C 273: BeppoSAX results

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We present the results of BeppoSAX AO1 Core Program observations of 3C 273 performed in Jan. 1997 and compare them in detail with data obtained during the satellite Science Verification Phase (SVP), in Jul. 1996. Though a power law is an acceptable representation of the data in the whole 0.1-200 keV range, there is indication of a steepening of the spectrum as the energy increases. Our data mark a difference with respect to the SVP data, where a steeper power law below 0.5 keV, an absorption feature at 0.6 keV, and a more prominent fluorescence iron line have been found. The weakening of cold/warm matter signatures in our data with respect to the SVP ones may indicate that, at higher luminosities, the featureless continuum produced in a relativistic jet overwhelms any thermal and/or reprocessed radiation, while the two components were almost comparable during the lower state of Jul. 1996. We conclude that this radio--loud source shows evidence not only for thermal disk--like emission, but also substantial reprocessing of X-rays onto cold matter.