Arp 299: A Second Merging System with Two Active Nuclei?

Recent BeppoSAX observations of Arp 299, a powerful far-IR merging starburst system composed of IC 694 and NGC 3690, clearly unveiled for the first time in this system the presence of a strongly absorbed active galactic nucleus (AGN). However, the system was not spatially resolved by BeppoSAX. Here we present the analysis of archival Chandra and (for the first time) XMM- Newton observations, which allow us to disentangle the X-ray emission of the two galaxies. The detection of a strong 6.4 keV line in NGC 3690 clearly demonstrates the existence of an AGN in this galaxy, while the presence of a strong 6.7 keV Fe-Kalpha line in the spectrum of IC 694 suggests that this nucleus might also harbor an AGN. This would be the second discovery of two AGNs in a merging system after NGC 6240.