A New Sample of Obscured AGNs Selected from the XMM-Newton and AKARI
  Surveys
  We report a new sample of obscured active galactic nuclei (AGNs) selected
from the XMM serendipitous source and AKARI point-source catalogs. We match
X-ray sources with infrared (18 and 90 micron) sources located at |b|>10 deg to
create a sample consisting of 173 objects. Their optical classifications and
absorption column densities measured by X-ray spectra are compiled and study
efficient selection criteria to find obscured AGNs. We apply the criteria (1)
X-ray hardness ratio defined by using the 2-4.5 keV and 4.5-12 keV bands >-0.1
and (2) EPIC-PN count rate (CR) in the 0.2-12 keV to infrared flux ratio
CR/F90<0.1 or CR/F18<1, where F18 and F90 are infrared fluxes at 18 and 90
micron in Jy, respectively, to search for obscured AGNs. X-ray spectra of 48
candidates, for which no X-ray results have been published, are analyzed and
X-ray evidence for the presence of obscured AGNs such as a convex shape X-ray
spectrum indicative of absorption of NH~10^{22-24} cm^-2, a very flat
continuum, or a strong Fe-K emission line with an equivalent width of >700 eV
is found in 26 objects. Six among them are classified as Compton-thick AGNs,
and four are represented by either Compton-thin or Compton-thick spectral
models. The success rate of finding obscured AGNs combining our analysis and
the literature is 92% if the 18 micron condition is used. Of the 26 objects, 4
are optically classified as an HII nucleus and are new "elusive AGNs" in which
star formation activity likely overwhelms AGN emission in the optical and
infrared bands.
