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XMM-Newton observations of ULIRGs I: A Compton-thick AGN in IRAS19254-7245

V. Braito·A. Franceschini·R. Della Ceca·P . Severgnini·L. Bassani·M. Cappi·G. Malaguti·G. G. C. Palumbo·M. Persic·G. Risaliti·M. Salvati
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Abstract

We present the XMM-Newton observation of the merging system IRAS 19254-7245, also known as The Superantennae, whose southern nucleus is classified as a Seyfert 2 galaxy. The XMM-Newton data have allowed us to perform a detailed X-ray imaging and spectral analysis of this system. We clearly detect, for the first time in this system, a strong EW ~ 1.4 keV Fe emission line at 6.49+/-0.1 keV (rest-frame). The X-ray spectrum requires a soft thermal component (kT~0.9 keV; L(0.5-2) ~ 4E41 cgs), likely associated with the starburst, and a hard power-law continuum above 2 keV (observed L(2-10) ~ 4E42 cgs). We confirm the flatness of this latter component, already noted in previous ASCA data. This flatness, together with the detection of the strong Fe-Kalpha line and other broad band indicators, suggest the presence of a Compton-thick AGN with intrinsic luminosity > 1E44 cgs. We show that a Compton-thick model can perfectly reproduce the X-ray spectral properties of this object.

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V. Braito, A. Franceschini, R. Della Ceca, P . Severgnini, L. Bassani, M. Cappi, G. Malaguti, G. G. C. Palumbo, M. Persic, G. Risaliti, M. Salvati. 2002-11-12. XMM-Newton observations of ULIRGs I: A Compton-thick AGN in IRAS19254-7245. https://doi.org/10.1051/0004-6361%3A20021633

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