Abstract

We have analyzed the broadband X-ray spectra of active galactic nuclei (AGNs) in two "nonmerging" luminous infrared galaxies (LIRGs), UGC.2608 and NGC.5135, utilizing the data of Nuclear Spectroscopic Telescope Array, Suzaku, XMM-Newton, and Chandra. Applying the X-ray clumpy-torus model (XCLUMPY), we find that both sources have similar spectra characterized by Compton-thick (CT) absorption (N-H similar to 5-7 x 10(24) cm(-2)) and small torus angular width (sigma < 20 degrees). The intrinsic 2-10.keV luminosities are 3.9(-1.7)(+2.2) x 10(43) erg s(-1) (UGC 2608) and 2.0(-0.9)(+3.3) x 10(43) erg s(-1) (NGC 5135). The [O IV]-to-nuclear-12 mu m luminosity ratios are larger than those of typical Seyferts, which are consistent with the torus covering factors (C-T less than or similar to 0.7) estimated from the torus angular widths and column densities by X-ray spectroscopy. The torus covering factors and Eddington ratios (lambda(Edd) similar to 0.1) follow the relation found by Ricci et al. for local AGNs, implying that their tori become geometrically thin, due to significant radiation pressure of the AGN that blows out some part of the tori. These results indicate that the CT AGNs in these "nonmerger" LIRGs are just a normal AGN population seen edge-on through a large line-of-sight column density. They are in contrast to the buried CT AGNs in late-stage mergers that have large torus covering factors even at large Eddington ratios.