J1615+5452: a remnant radio galaxy in the ELAIS-N1 field
  We report the discovery of a remnant radio AGN J1615+5452 in the field of
ELAIS-N1. GMRT continuum observations at 150, 325 and 610 MHz combined with
archival data from the 1.4 GHz NVSS survey were used to derive the radio
spectrum of the source. At a redshift $z \sim$ 0.33, J1615+5452 has a linear
size of $\sim$ 100 kpc and spectral indices ranging between
$\alpha^{1400}_{610} < -1.5$ and $\alpha^{325}_{150} = -0.61 \pm 0.12$. While
the source has a diffuse radio emission at low frequencies, we do not find
evidence of core, jets or hotspots in the 1.4\,GHz VLA data of $\sim 5$ arcsec
angular resolution. Such morphological properties coupled with a curved radio
spectrum suggest that the AGN fueling mechanisms undergo a shortage of energy
supply which is typical of a dying radio AGN. This is consistent with the
observed steep curvature in the spectrum $\Delta\alpha \approx -1$, the
estimated synchrotron age of $t_{\rm s}=76.0^{+7.4}_{-8.7}$ Myr and a $t_{\rm
off}/t_{\rm s}$ ratio of $\sim 0.3$.
