NGC 4151: an intrinsically average Seyfert 1

We present a detailed analysis of a long, 100 ksec, observation of NGC 4151 by ASCA, contemporaneous with an observation by the CGRO/OSSE. We fit the data with physical models including Fe K line and Compton reflection both relativistically broadened and coupled according to theoretical results. The ASCA data show strong evidence for rather complex absorption in the source. Taking it into account, our best intrinsic model consists of a Comptonization continuum with the X-ray slope of Gamma = 1.9 coming from a thermal plasma at an electron temperature of about 70 keV, and a disk line with the equivalent width of about 70 eV. The broadening of the line and reflection indicate their origin from innermost parts of an accretion disk. Our results resolve the long-standing discrepancy between the X-ray parameters of NGC 4151 and those of average Seyfert 1s. We also show that the X-ray variability properties of this source are fully consistent with those of other Seyfert 1s