AAS 204th Meeting, June 2004
Session 60 Quasars
Poster, Wednesday, June 2, 2004, 10:00am-7:00pm, Ballroom

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[60.04] The X-ray Spectrum and Variability of Radio Galaxy 3C 120

P. M. Ogle (JPL/NRC), S. W. Davis, R. R. J. Antonucci (UCSB), J. W. Colbert (IPAC), M. A. Malkan (UCLA), M. J. Page (MSSL/UCL), T. P. Sasseen (UCSB), M. Tornikoski (Metsahovi/Helsinki UT)

We present a long (120 ks) XMM-Newton observation of the radio galaxy 3C 120. The continuum is characterized by a power law at 2-10 keV and an unusual soft excess bump from 0.3-2 keV. The bump is too narrow to characterize with a blackbody spectrum, and may be affected by absorption below 0.6 keV. We consider possible origins of this bump, including Comptonization in a thick disk.

The hard and soft X-ray continua vary together, with a nominal pivot point at >10 keV. Simultaneous UV observations with the XMM Optical Monitor show correlated variations with the X-ray flux, with no perceptible lag (<10 ks). This is qualitatively consistent with Comptonization of UV photons producing both X-ray emission components. 3C 120 was undergoing a bright radio flare at 250 GHz, which developed into a flare at 37 GHz 7 days after the XMM observation. However, the X-ray emission does not appear to be affected by the activity of the radio jet at this epoch.

Contrary to previous claims, there is no relativistically broadened Fe-K emission in the X-ray spectrum. Instead, we find narrow Fe K\alpha and K\beta lines. The equivalent widths of the Fe lines are consistent with reflection from cold gas with a covering fraction of 0.4. The Fe-K lines are unresolved, and may come from either the broad line region or a molecular torus. We find a weak, narrow emission line from O {\sc viii} Ly\alpha in the soft X-ray spectrum. However, there is no evidence for any ionized absorption along the line of sight, which is close to the radio axis.

The research was made possible by the National Research Council, NASA, JPL, and the ESA XMM-Newton mission.

The author(s) of this abstract have provided an email address for comments about the abstract: Patrick.M.Ogle@jpl.nasa.gov

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