The Ultra Luminous Infrared Galaxy Mrk 231: new clues from BeppoSAX and XMM-Newton

We present BeppoSAX and XMM-Newton observations of Mrk 231. These observations and in particular the BeppoSAX PDS data allowed us to unveil, for the first time, the highly absorbed (N_H~2×10²⁴ cm^-2) AGN component. We find that: a) the AGN powering Mrk 231 has an intrinsic 2-10 keV luminosity of 1⁺¹_-0.5×10⁴⁴ erg s^-1 b) the strong starburst activity contributes significantly in the 0.1-10 keV energy range. We propose that the starburst activity strongly contributes to the far infrared luminosity of Mrk 231; this is also suggested by the multiwavelength properties of Mrk 231.