The XMM-Newton and BeppoSAX view of the Ultra Luminous Infrared Galaxy MKN 231
Cappi, M.; Franceschini, A.; Piconcelli, E.; Iwasawa, K.; Marziani, P.; Malaguti, G.; Bassani, L.; Braito, V.; Severgnini, P.; Della Ceca, R.; Persic, M.; Salvati, M.; Risaliti, G.; Palumbo, G. G. C.
Italy, Spain, United Kingdom, United States
Abstract
We discuss XMM-Newton and BeppoSAX observations of MKN 231, the lowest-redshift Broad Absorption Line (BAL) QSO known so far and one of the best-studied Ultra Luminous Infrared Galaxies. By combining the XMM-Newton spectral resolution and the high-energy bandpass of BeppoSAX we have been able to study in more detail than previously possible its 0.2-50 keV spectral properties. The BeppoSAX PDS data unveiled, for the first time, a highly absorbed (NH∼ 2× 1024 cm-2) power-law component. We find that: a) below 10 keV we are seeing only reprocessed radiation through reflection and/or scattering; b) the intrinsic 2-10 keV luminosity of MKN 231 is 1+1.0-0.5 × 1044 erg s-1, i.e. more than an order of magnitude greater than previous measurements; c) the starburst activity significantly contributes to the soft (E<2 keV) X-ray emission.