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arXiv · 1106.1647

On the nature of the absorber in IRAS 09104+4109: the X-ray and mid-infrared view

C. Vignali·E. Piconcelli·G. Lanzuisi·A. Feltre·C. Feruglio·R. Maiolino·F. Fiore·J. Fritz·V. La Parola·M. Mignoli·F. Pozzi
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Abstract

We present a long (~76 ks) Chandra observation of IRAS 09104+4109, a hyper-luminous galaxy, optically classified as a Type 2 AGN hosted in a cD galaxy in a cluster at z=0.442. We also report on the results obtained by fitting its broad-band spectral energy distribution. The Compton-thick nature of this source (which has been often referred to as an "archetype" of Compton-thick Type 2 quasars) was formerly claimed on the basis of its marginal detection in the PDS instrument onboard BeppoSAX, being then disputed using XMM-Newton data. Both Chandra analysis and optical/mid-IR spectral fitting are consistent with the presence of heavy (~1-5 10^{23} cm^{-2}) but not extreme (Compton-thick) obscuration. However, using the mid-IR and the [OIII] emission as proxies of the nuclear hard X-ray luminosity suggests the presence of heavier obscuration. The 54-month Swift BAT map shows excess hard X-ray emission likely related to a nearby (z=0.009) Type 2 AGN, close enough to IRAS 09104+4109 to significantly enhance and contaminate its emission in the early BeppoSAX PDS data.

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C. Vignali, E. Piconcelli, G. Lanzuisi, A. Feltre, C. Feruglio, R. Maiolino, F. Fiore, J. Fritz, V. La Parola, M. Mignoli, F. Pozzi. 2011-09-20. On the nature of the absorber in IRAS 09104+4109: the X-ray and mid-infrared view. https://doi.org/10.1111/j.1365-2966.2011.19181.x

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