COMP2CAT: hunting compact double radio sources in the local Universe^⋆

¹ Dipartimento di Fisica, Università degli Studi di Torino, Via Pietro Giuria 1, 10125 Torino, Italy
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² INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese, Italy
³ Istituto Nazionale di Fisica Nucleare, Sezione di Torino, 10125 Torino, Italy
⁴ Consorzio Interuniversitario per la Fisica Spaziale (CIFS), Via Pietro Giuria 1, 10125 Torino, Italy
⁵ Departamento de Astrofísica, Universidad de La Laguna, 38206 La Laguna, Tenerife, Spain
⁶ Instituto de Astrofísica de Canarias (IAC), 38200 La Laguna, Tenerife, Spain
⁷ Department of Physics and Astronomy, University of Southampton, Highfield SO17 1BJ, UK
⁸ Department of Theoretical Physics and Astrophysics, Faculty of Science, Masaryk University, Kotlářská 2, Brno 611 37, Czech Republic
⁹ Smithsonian Astrophysical Center, 60 Garden Street, Cambridge, MA 02138, USA

Received: 22 January 2019
Accepted: 13 March 2019

Abstract

We present a catalog of compact double radio galaxies (hereafter COMP2CAT) listing 43 edge-brightened radio sources whose projected linear size does not exceed 60 kpc, the typical size of their host galaxies. This is the fifth in a series of radio source catalogs recently created, namely: FRICAT, FRIICAT, FR0CAT, and WATCAT, each of which focuses on a different class of radio galaxies. The main aim of our analysis is to attain a better understanding of sources with intermediate morphologies between FR IIs and FR 0s. COMP2CAT sources were selected from an existing catalog of radio sources based on NVSS, FIRST and SDSS observations because they have (i) edge-brightened morphologies typical of FR IIs, (ii) redshifts z <  0.15, and (iii) projected linear sizes smaller than 60 kpc. With radio luminosities at 1.4 GHz 10³⁸ ≲ L_1.4 ≲ 10⁴¹ erg s⁻¹, COMP2CAT sources appear as the low radio luminosity tail of FR IIs. However, their host galaxies are indistinguishable from those of large-scale radio sources: they are luminous (−21 ≳ M_r ≳ −24), red, early-type galaxies with black hole masses in the range 10^7.5 ≲ M_BH ≲ 10^9.5 M_⊙. Moreover, all but one of the COMP2CAT sources are optically classifiable as low-excitation radio galaxies, in agreement with being the low radio luminosity tail of FR Is and FR IIs. This catalog of compact double sources, which is ∼47% complete at z <  0.15, can potentially be used to clarify the role of compact double sources in the general evolutionary scheme of radio galaxies.