The MURALES survey

We present the results of VLT/MUSE integral-field spectroscopy of the radio galaxy 3C 313 at z = 0.459, combined with HST and Chandra images. The high-resolution optical and X-ray images show the presence of two sources separated by 0.​​″63 (3.7 kpc). The narrow emission lines produced by highly ionized gas show a double-peaked profile, with a separation corresponding to ∼400 km s−1. No permitted broad lines are observed. We conclude that 3C 313 hosts a dual active galactic nucleus (AGN), with both nuclei being optically obscured type II. The low ionization [O <ns0:sc>II</ns0:sc>] line instead has a single profile, and it was likely produced by the large scale, low-density interstellar medium. 3C 313 is the second dual AGN discovered among the 63 sources observed as part of the MURALES survey. Besides the emission associated with the two nuclei, we found a tail of line emission extending for ∼18 kpc aligned with the radio structure. We interpret this structure as a nuclear outflow of ionized gas.