XMM-Newton Detection of a Compton-thick AGN in the 1 Jy ULIRG/UNER F04103-2838

We report on the detection of Fe Ka emission in F04103-2838, an ultraluminous Infrared galaxy [ULIRG; log (L sub(m)/L [unk]) greater than or equal to 12 ] optically classified as a LINER. Previous Chandra observations suggested the presence of both a starburst and an active galactic nucleus (AGN) in this source. A deeper ( similar to 20 ks) XMM-Newton spectrum reveals an Fe Ka line at rest-frame energy similar to 6.4 keV, which is consistent with cold neutral iron. The best-fit spectral model Indicates that the Fe Ka line has an equivalent width of similar to 1.6 keV. The hard X-ray emission is dominated by a Compton-thick AGN with an Intrinsic 0.2-10 keV luminosity of similar to 10 super(44) ergs s super(-1), while the soft X-ray emission is from similar to 0.1 keV gas attributed to the starburst. The X-ray spectrum of this source bears a striking resemblance to that of the archetypal luminous infrared galaxy NGC 6240, despite differences in merger state and infrared properties.