8th HEAD Meeting, 8-11 September, 2004
Session 9 Jets and Blazars
Oral, Wednesday, September 8, 2004, 11:00am-12:30pm

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[9.03] Jet and Accretion Disk Emission Untangled in 3C273

G. G. C. Palumbo (Bologna University, Italy), P. Grandi (IASF/CNR, Bologna Italy)

A long-term spectral variability study of 3C273 on data obtained by BeppoSAX has allowed, for the first time, to decouple the beamed and unbeamed radiation produced in the nucleus of a Radio-Loud AGN. The 0.1-200 keV average spectrum of 3C273 is adequately reproduced by a jet emission modeled with a hard power law and a Seyfert-like component parametrized by a softer power law (with a high energy cut off) reflected by cold matter. Furthermore a black body is also necessary to model a soft excess. Black body and Seyfert-like fluxes vary together, suggesting a physical connection. This is expected if an accretion disk is responsible for the soft excess and a nearby hot plasma for the Compton scattered radiation represented by the softer power law with an exponential cutoff. The jet (the harder power law) varies indipendently, like a separate component. The Seyfert-like component is generally overwhelmed by the beamed radiation by a factor 2-5 in the 2-10 keV range and up to a factor of 10 above 20 keV. Only in one case, the accretion flow overcomes the jet by a factor of about 1.3 allowing the reprocessed features to clearly emerge over the continuum. Coherently with this picture, the equivalent width of the Fe line is small (below 30 eV), if measured respect to the total continuum flux dominated by the jet, but approaches Seyfert values, if measured respect to the accretion flow radiation alone.

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Bulletin of the American Astronomical Society, 36 #3
© 2004. The American Astronomical Soceity.