FE-K-EMISSION FROM THE HIDDEN QUASAR IRAS-P09104+4109

We report the discovery of a strong Fe K line in the ASCA spectrum of the infrared-luminous galaxy IRAS P09104+4109 at a redshift z = 0.442. It is the most distant Fe K emission line detected so far. The large equivalent width (EW similar to 450 eV) and X-ray continuum spectrum, which has Gamma approximate to 2.0 with little absorption, favors a model in which the observed X-rays are scattered into our line of sight from a hidden quasar. Previous work has shown that the source has strong narrow emission lines and a highly polarized continuum in the optical and a strong infrared excess, similar to Seyfert 2 galaxies. The observed X-ray luminosity is L(X) approximate to 2 x 10(45) ergs s(-1) in the rest frame 2-10 keV band; the large obscuration suggested by the optical and infrared studies implies that the hidden quasar has an intrinsic luminosity of L(Bol) = 5 x 10(47) ergs s(-1). Our results indicate that IRAS P09104+4109 is the prototype of a new class of Seyfert 2 nuclei, which emit at quasar luminosities.