iPTF Discovery of the Rapid "Turn On" of a Luminous Quasar

摘要: We present a radio-quiet quasar at z=0.237 discovered "turning on" by the intermediate Palomar Transient Factory (iPTF). The transient, iPTF 16bco, was detected in nucleus of galaxy with an archival SDSS spectrum weak narrow-line emission characteristic low-ionization line region (LINER). Our follow-up spectra show dramatic appearance broad Balmer lines and power-law continuum luminous (L_bol~10^45 erg/s) type 1 12 years later. photometric monitoring PTF from 2009-2012, serendipitous X-ray observations XMM-Newton Slew Survey 2011 2015, constrain change state to have occurred less than 500 days before detection. An enhanced Halpha [OIII]5007 ratio relative other changing-look quasars also is suggestive most rapid yet observed quasar. argue that >10 increase Eddington inferred brightening UV flux more likely due intrinsic accretion rate pre-existing disk, external mechanism such as variable obscuration, microlensing, or tidal disruption star. However, further will be helpful better constraining driving this state. "turn much shorter viscous infall timescale requires disk instability can develop around ~10^8 M_sun black hole on timescales year.