VizieR Online Data Catalog: Obscured AGNs from XMM-Newton and AKARI (Terashima+, 2015)
Abstract
We report a new sample of obscured active galactic nuclei (AGNs) selected from the XMM-Newton serendipitous source and AKARI point-source catalogs. We match X-ray sources with infrared (18 and 90μm) sources located at |b|>10° 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 2-4.5keV and 4.5-12keV bands >-0.1 and (2) EPIC-PN count rate (CR) in the 0.2-12keV to infrared flux ratio CR/F90<0.1 or CR/F18<1 where F18 and F90 are infrared fluxes at 18 and 90μm 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~1022-24/cm2, a very flat continuum, or a strong Fe-K emission line with an equivalent width of >700eV is found in 26 objects. Six of 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 18μm 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.
(6 data files).- Publication:
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VizieR Online Data Catalog
- Pub Date:
- February 2016
- DOI:
- 10.26093/cds/vizier.18140011
- Bibcode:
- 2016yCat..18140011T
- Keywords:
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- Active gal. nuclei;
- X-ray sources;
- Galaxies: IR;
- Surveys;
- Redshifts;
- Cross identifications