- ID:
- ivo://nasa.heasarc/nwayawgros
- Title:
- AllWISE Counterparts and Gaia Matches to ROSAT/2RXS X-Ray Sources
- Short Name:
- NWAYAWGROS
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the 132,254 AllWISE counterparts and/or Gaia matches to 106,573 X-ray sources detected in the ROSAT 2RXS survey with Galactic latitude |b| > 15 degrees. These are the brightest X-ray sources in the sky, but their position uncertainties and the sparse multi-wavelength coverage until now rendered the identification of their counterparts a demanding task with uncertain results. New all-sky multi-wavelength surveys of sufficient depth, like AllWISE and Gaia, and a new Bayesian statistics-based algorithm, NWAY, allow us, for the first time, to provide reliable counterpart associations. NWAY extends previous distance- and sky density-based association methods and, using one or more priors (e.g. colors, magnitudes), weights the probability that sources from two or more catalogs are simultaneously associated on the basis of their observable characteristics. Here, counterparts have been determined using a Wide-field Infrared Survey Explorer (WISE) color-magnitude prior. A reference sample of 4,524 XMM/Chandra and Swift X-ray sources demonstrates a reliability of 94.7 per cent for 2RXS sources. Combining the results of this work and of the matching of XMM-Newton Slew Survey, Version 2 (XMMSL2) sources also reported in this study (the results of the latter are available as the HEASARC's database table NWAYAWGXMM) with Chandra-COSMOS data, the authors propose a new separation between stars and AGN in the X-ray/WISE flux-magnitude plane, that is valid over six orders of magnitude. The authors also release the NWAY code and its user manual. NWAY was extensively tested with XMM-COSMOS data. Using two different sets of priors, the authors find an agreement of 96 per cent and 99 per cent with published Likelihood Ratio methods. Their results were achieved faster and without any follow-up visual inspection. With the advent of deep and wide area surveys in X-rays (e.g. SRG/eROSITA, Athena/WFI) and radio (ASKAP/EMU, LOFAR, APERTIF, etc.), NWAY will provide a powerful and reliable counterpart identification tool. For all the available options, see the NWAY manual at <a href="https://github.com/JohannesBuchner/nway/raw/master/doc/nway-manual.pdf">https://github.com/JohannesBuchner/nway/raw/master/doc/nway-manual.pdf</a>. This table was created by the HEASARC in February 2018 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/473/4937">CDS catalog J/MNRAS/473/4937</a> file 2rxswg.dat. This is a service provided by NASA HEASARC .
1 - 2 of 2
Number of results to display per page
Search Results
- ID:
- ivo://nasa.heasarc/wibrals
- Title:
- WISE Blazar-like Radio-Loud Source (WIBRaLS) Catalog
- Short Name:
- WIBRALS
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- 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 .
