The MURALES survey

II. Presentation of MUSE observations of 20 3C low-z radio galaxies and first results

¹ INAF – Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese, Italy
e-mail: balmaverde@oato.inaf.it
² Dipartimento di Fisica e Astronomia, Università di Firenze, Via G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy
³ INAF – Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, 50125 Firenze, Italy
⁴ Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21210, USA
⁵ Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
⁶ Department of Physics and Astronomy, University of Southampton, Highfield SO17 1BJ, UK
⁷ INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, via Gobetti 93/3, 40129 Bologna, Italy
⁸ Department of Physics and Astronomy, University of Manitoba Winnipeg, MB R3T 2N2, Canada
⁹ Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
¹⁰ Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138, USA
¹¹ University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
¹² School of Physics & Astronomy, Rochester Institute of Technology, Rochester, NY 14623, USA
¹³ Carlson Center for Imaging Science, Rochester Institute of Technology, Rochester, NY 14623, USA
¹⁴ SETI Institute, 189 N. Bernado Ave, Mountain View, CA 94043, USA
¹⁵ Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile

Received: 26 March 2019
Accepted: 3 October 2019

Abstract

We present observations of a complete sub-sample of 20 radio galaxies from the Third Cambridge Catalog (3C) with redshift < 0.3 obtained from VLT/MUSE optical integral field spectrograph. These data have been obtained as part of the survey MURALES (a MUse RAdio Loud Emission line Snapshot survey) with the main goal of exploring the active galactic nuclei (AGN) feedback process in a sizeable sample of the most powerful radio sources at low redshift. We present the data analysis and, for each source, the resulting emission line images and the 2D gas velocity field. Thanks to their unprecedented depth (the median 3σ surface brightness limit in the emission line maps is 6 × 10⁻¹⁸ erg s⁻¹ cm⁻² arcsec⁻²), these observations reveal emission line structures extending to several tens of kiloparsec in most objects. In nine sources the gas velocity shows ordered rotation, but in the other cases it is highly complex. 3C sources show a connection between radio morphology and emission line properties. Whereas, in three of the four Fanaroff and Riley Class I radio galaxies (FR Is), the line emission regions are compact, ∼1 kpc in size; in all but one of the Class II radiogalaxies FR IIs, we detected large scale structures of ionized gas with a median extent of 17 kpc. Among the FR IIs, those of high and low excitation show extended gas structures with similar morphological properties, suggesting that they both inhabit regions characterized by a rich gaseous environment on kpc scale.