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WISE Blazar-like Radio-Loud Source (WIBRaLS) Catalog

Published by High Energy Astrophysics Science Archive Research Center | National Aeronautics and Space Administration | Metadata Last Checked: February 14, 2026 | Last Modified: 2026-02-10
This table contains a catalog of radio-loud candidate gamma-ray emitting blazars with WISE mid-infrared colors similar to the colors of confirmed gamma-ray blazars. The catalog is assembled from WISE sources detected in all four WISE filters, with colors that are compatible with the three-dimensional locus of the WISE gamma-ray emitting blazars, and which can be spatially cross-matched with radio sources from one of the three radio surveys: NVSS, FIRST, and/or SUMSS. The authors' initial WISE selection uses a slightly modified version of previously successful algorithms. They then select only the radio-loud sources using a measure of the radio-to-IR flux, the q<sub>22</sub> parameter, which is analogous to the q<sub>24</sub> parameter known in the literature but which instead uses the WISE band-four flux at 22 micron (µm). Their final catalog contains 7,855 sources classified as BL Lacs, FSRQs, or mixed candidate blazars; 1,295 of these sources can be spatially re-associated as confirmed blazars. In their paper, the authors describe the properties of the final catalog of WISE blazar-like radio-loud sources and consider possible contaminants. Finally, they discuss why this large catalog of candidate gamma-ray emitting blazars represents a new and useful resource to address the problem of finding low-energy counterparts to currently unidentified high-energy sources. The WISE magnitudes in the [3.4], [4.6], [12] and [22] um nominal filters are in the Vega system. The values of three WISE magnitudes, namely [3.4], [4.6], and [12], and of the colors derived using those magnitudes, have been corrected for galactic extinction according to the extinction law presented by Draine (2003, ARA&A, 41, 241). In their study, the authors adopt the nomenclature proposed in the Multi-wavelength Blazar Catalog (BZCat) that labels BL Lac objects as 'BZBs' and flat-spectrum radio quasars (FSRQs) as 'BZQs'. This table was created by the HEASARC in December 2014 based on a machine-readable version of Table 4 from the reference paper that was obtained from the ApJS web site. This is a service provided by NASA HEASARC .

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