We have obtained a hard X-ray spectrum of the ultraluminous infrared galaxy IRAS 20210+1121 (z=0.056), whose optical spectrum is that of a Seyfert 2. The most significant feature is a strong Fe K line at 6.7 (6.5-7.0) keV in the lest-frame with equivalent width about 1 keV. This suggests that the observed X-ray continuum is scattered emission from a completely blocked AGN, a situation similar to that in NGC 1068. However, IRAS 20210+1121 has an observed 2-10 keV luminosity of 4 x 10(42) erg s(-1) (assuming H-0 = 50km s(-1) Mpc(-1)), about ten times higher than NGC 1068. If the scattering efficiencies of NGC 1068 and IRAS 20210 are similar, then this implies the presence of an extremely luminous X-ray source in IRAS 20210.
Ueno, S., Ward, M.j., O'Brien, P.t., Stirpe, G.m., Matt, G. (1999). The BeppoSAX observation of IRAS 20210+1121. NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS, 69(1-3), 554-557 [10.1016/S0920-5632(98)00287-4].