Caltech-NRAO Stripe 82 Survey (CNSS). IV. The Birth of Radio-loud Quasar 013815+00
M. Kunert‐Bajraszewska, Aleksandra Wołowska, K. P. Mooley, Preeti Kharb, Gregg Hallinan
Abstract
Abstract It is believed that the gas accretion onto supermassive black holes is the main process of powering this quasar’s luminous emission, which occurs in optical, UV, and X-ray regimes and less frequently in radio waves. The observational fact that only a few percent of quasars are radio-loud is still an unresolved issue concerning the understanding of the active galactic nucleus (AGN) population. Here we present a detection of a rapid transition from the radio-quiet to the radio-loud mode in quasar 013815+00 ( z = 0.94) which coincides with changes of its UV–optical continuum and the low ionization Mg ii broadline. We interpret this as an enhancement of accretion onto a central black hole of about 10 9 solar masses. As a consequence a new radio-loud AGN was born. Its spectral and morphological properties indicate that it went through the short gigahertz-peaked spectrum phase at the beginning of its activity and has now stabilized its flux density at the level of a few millijansky. The radio morphology of 013815+00 is very compact and we predict that with such short-term jet activity its development will be very slow. The observed luminosity changes of the accretion disk are shorter than the lifetime of the new radio phase in 013815+00.