Low-luminosity X-ray active galactic nuclei in S0 galaxies NGC 3065 and NGC 4203

We present ASCA X-ray results on two SO galaxies, NGC 3065 and NGC 4203. In both galaxies, we detected hard X-ray emission from a pointlike source at the nucleus. A single power-law model having a photon index of similar to 1.8 well described the spectra of these sources, while thin thermal emission, which is common in SO galaxies, was not detected. The 2-10 keV luminosities of these nuclear sources (2.2 x 10(41) and 1.5 x 10(40) ergs s(-1)) are 1-2 orders of magnitude higher than those expected as an assembly of low-mass X-ray binaries in these galaxies. Our results strongly suggest that NGC 3065 and NGC 4203 host low-luminosity active galactic nuclei.