BASALT faint blazar candidates Virtual Observatory Resource

Authors
  1. Casadei S.
  2. Raiteri C.M.
  3. Carnerero M.I.
  4. Capetti A.
  5. Massaro F.
  6. Published by
    CDS
Abstract

We present a sample of blazar candidates from the Very Large Array Sky Survey (VLASS) catalog, with cross-referencing to optical and infrared data from the Panoramic Survey Telescope & Rapid Response System (Pan-STARRS) and the Wide-Field Infrared Survey Explorer (WISE), respectively. We focus on compact radio sources and employ a multistage selection process to minimize contamination from non-blazar sources. We considered constraints derived from the radio-optical spectral index and from the infrared and optical colors. We identified the variable objects through an optical variability analysis of Pan-STARRS light curves using two reference samples of stars. We further selected sources whose variability exceeds the level observed in quasars. This led to the selection of 3467 candidates with blazar-like properties and strong optical variability. Only 45% is available in other blazar candidate catalogs, with the remainder representing new identifications. In particular, we unveil a large population of faint sources, down to r~20.5. The blazar nature of a subsample of these sources is confirmed by available spectra. Our work offers new insights into the blazar population and serves as a foundation for future variability studies, especially in view of the upcoming Legacy Survey of Space and Time at the Vera C. Rubin Observatory, which will reach even fainter sources.

Keywords
  1. bl-lacertae-objects
  2. radio-galaxies
  3. infrared-photometry
  4. visible-astronomy
Bibliographic source Bibcode
2026A&A...708A.220C
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/708/A220
IVOA Identifier IVOID
ivo://CDS.VizieR/J/A+A/708/A220

Access

Web browser access HTML
https://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/708/A220
https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/708/A220
http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/708/A220
IVOA Table Access TAP
https://tapvizier.cds.unistra.fr/TAPVizieR/tap
Run SQL-like queries with TAP-enabled clients (e.g., TOPCAT).
IVOA Cone Search SCS
For use with a cone search client (e.g., TOPCAT).
https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/708/A220/catalog?
https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/708/A220/catalog?
http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/708/A220/catalog?

History

2026-04-08T12:56:47Z
Resource record created
2026-04-08T11:57:21Z
Updated
2026-04-08T12:56:47Z
Created

Contact

Name
CDS support team
Postal Address
CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France
E-Mail
cds-question@unistra.fr