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

Understand

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 by iPTF in the nucleus of a galaxy with an archival SDSS spectrum with weak narrow-line emission characteristic of a low-ionization emission line region (LINER).
• Our follow-up spectra show the dramatic appearance of broad Balmer lines and a power-law continuum characteristic of a luminous (L_bol~10^45 erg/s) type 1 quasar 12 years later.
• Our photometric monitoring with PTF from 2009-2012, and serendipitous X-ray observations from the XMM-Newton Slew Survey in 2011 and 2015, constrain the change of state to have occurred less than 500 days before the iPTF detection.