Broad Band X-Ray Spectra of Two Low-luminosity Active Galactic Nuclei
  NGC 1566 and NGC 4941
  We report the first broad band X-ray spectra of the low luminosity active
galactic nuclei (LLAGN) NGC 1566 (type 1.5) and NGC 4941 (type 2) observed with
Suzaku and Swift/BAT covering the 0.5-195 keV band. Both targets have hard
X-ray luminosities of ~ 10^{41-42} ergs/s in the 15-55 keV band. The spectra of
the nucleus are well reproduced by a sum of partially or fully covered
transmitted emission and its reflection from the accretion disk, reprocessed
emission from the torus accompanied by a strong narrow iron-K\alpha line, and a
scattered component (for NGC 4941). We do not significantly detect a broad
iron-K\alpha line from the inner accretion disk in both targets, and obtain an
upper limit on the corresponding solid angle of \Omega/2\pi < 0.3 in NGC 1566.
The reflection strength from the torus is moderate, \Omega/2\pi
=0.45^{+0.13}_{-0.10} in NGC 1566 and \Omega/2\pi =0.64^{+0.69}_{-0.27} in NGC
4941. Comparison of the equivalent width of the narrow iron-K\alpha line with a
model prediction based on a simple torus geometry constrains its half-opening
angle to be \theta_oa ~ 60-70 degree in NGC 4941. These results agree with the
obscured AGN fraction obtained from hard X-ray and mid-infrared selected
samples at similar luminosities. Our results support the implication that the
averaged covering fraction of AGN tori is peaked at L 10^{42-43} ergs/s but
decreases toward lower luminosities.
