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We report a new sample of obscured active galactic nuclei (AGNs) selectedfrom the XMM serendipitous source and AKARI point-source catalogs. We matchX-ray sources with infrared (18 and 90 micron) sources located at |b|>10 deg tocreate a sample consisting of 173 objects. Their optical classifications andabsorption column densities measured by X-ray spectra are compiled and studyefficient 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 >-0.1and (2) EPIC-PN count rate (CR) in the 0.2-12 keV to infrared flux ratioCR/F90<0.1 or CR/F18<1, where F18 and F90 are infrared fluxes at 18 and 90micron in Jy, respectively, to search for obscured AGNs. X-ray spectra of 48candidates, for which no X-ray results have been published, are analyzed andX-ray evidence for the presence of obscured AGNs such as a convex shape X-rayspectrum indicative of absorption of NH~10^{22-24} cm^-2, a very flatcontinuum, or a strong Fe-K emission line with an equivalent width of >700 eVis found in 26 objects. Six among them are classified as Compton-thick AGNs,and four are represented by either Compton-thin or Compton-thick spectralmodels. The success rate of finding obscured AGNs combining our analysis andthe literature is 92% if the 18 micron condition is used. Of the 26 objects, 4are optically classified as an HII nucleus and are new "elusive AGNs" in whichstar formation activity likely overwhelms AGN emission in the optical andinfrared bands.

A New Sample of Obscured AGNs Selected from the XMM-Newton and AKARI Surveys