2018ApJ...858...49W

We report an identification of SDSS J141324+530527.0 (SBS 1411+533) at z = 0.456344 as a new "changing-look" quasar with a "turn-on" spectral type transition from Type-1.9/2 to Type-1 within a rest-frame timescale of 1-10 yr by a comparison of our new spectroscopic observation and the Sloan Digital Sky Survey (SDSS) archive database. The SDSS DR7 spectrum taken in 2003 is dominated by a starlight emission from host galaxy redward of the Balmer limit, and has a non-detectable broad Hβ line. The new spectrum taken by us on 2017 June 1 and the SDSS DR14 spectrum taken on 2017 May 29 indicate that the object has a typical quasar spectrum with a blue continuum and strong Balmer broad emission lines. In addition, an intermediate spectral type can be identified in the SDSS DR13 spectrum taken in 2015. The invariability of the line wing of Mg IIλ2800 emission and timescale argument (the invariability of [O III]λ5007 line blue asymmetry) suggests that a variation of obscuration (an accelerating outflow) is not a favorable scenario. The timescale argument allows us to believe the type transition is possibly caused by either a viscous radial inflow or a disk instability around a ∼(5–9)×10⁷M_☉ black hole.