Recognizing Blazars Using Radio Morphology from the VLA Sky Survey

The Astrophysical Journal, vol. 964, pp. 98

Abstract

Abstract Blazars are radio-loud active galactic nuclei whose jets have a very small angle to our line of sight. Observationally, the radio emissions are mostly compact or compact-core with a one-sided jet. With 2.″5 resolution at 3 GHz, the Very Large Array Sky Survey (VLASS) enables us to resolve the structure of some blazar candidates in the sky north of decl. −40°. We introduce an algorithm to classify radio sources as either blazar-like or non-blazar-like based on their morphology in the VLASS images. We apply our algorithm to three existing catalogs, including one of the known blazars (Roma-BzCAT) and two blazar candidates identified by Wide-field Infrared Survey Explorer colors and radio emission (WIBRaLS, KDEBLLACS). We show that in all three catalogs, there are objects with morphologies inconsistent with being blazars. Considering all the catalogs, more than 12% of the candidates are unlikely to be blazars, based on this analysis. Notably, we show that 3% of the Roma-BzCAT confirmed blazars could be a misclassification based on their VLASS morphology. The resulting table with all sources and their radio morphological classification is available online.

Authors 7

1. Zhang-Liang Xie
2. Eduardo Bañados

   Max Planck Institute for Astronomy

   Affiliation as printed

   Max Planck Institut für Astronomie, Königstuhl 17, D-69117, Heidelberg, Germany

3. S. Belladitta

   Max Planck Institute for Astronomy · Osservatorio di Astrofisica e Scienza dello Spazio · National Institute for Astrophysics

   Affiliation as printed

   INAF, Osservatorio di Astrofisica e Scienza dello Spazio, Via Gobetti 93/3, 40129 Bologna, Italy

   Max Planck Institut für Astronomie, Königstuhl 17, D-69117, Heidelberg, Germany

4. Chiara Mazzucchelli

   Universidad Diego Portales

   Affiliation as printed

   Instituto de Estudios Astrofísicos, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Avenida Ejercito Libertador 441, Santiago, Chile

5. Jan–Torge Schindler

   Universität Hamburg

   Affiliation as printed

   Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, D-21029 Hamburg, Germany

6. Frederick B. Davies

   Max Planck Institute for Astronomy

   Affiliation as printed

   Max Planck Institut für Astronomie, Königstuhl 17, D-69117, Heidelberg, Germany

7. Bram P. Venemans Aachen Leiden Observatory

   Leiden University · Leiden Observatory

   Affiliation as printed

   Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden, The Netherlands