PS1-13cbe: the rapid transition of a Seyfert 2 to a Seyfert 1. Issue 3 (5th June 2019)

• Record Type: Journal Article
• Authors: Katebi, Reza; Chornock, Ryan; Berger, Edo; Jones, David O; Lunnan, Ragnhild; Margutti, Raffaella; Rest, Armin; Scolnic, Daniel M; Burgett, William S; Kaiser, Nick; Kudritzki, Rolf-Peter; Magnier, Eugene A; Wainscoat, Richard J; Waters, Christopher
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 487:Issue 3(2019)
• Page Start: 4057
• Page End: 4070
• Publication Date: 2019-06-05
• Subjects: accretion, accretion discs -- black hole physics -- galaxies: active -- galaxies: nuclei; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stz1552
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We present a nuclear transient event, PS1-13cbe, that was first discovered in the Pan-STARRS1 survey in 2013. The outburst occurred in the nucleus of the galaxy SDSS J222153.87+003054.2 at z = 0.123 55, which was classified as a Seyfert 2 in a pre-outburst archival Sloan Digital Sky Survey (SDSS) spectrum. PS1-13cbe showed the appearance of strong broad H α and H β emission lines and a non-stellar continuum in a Magellan spectrum taken 57 d after the peak of the outburst that resembled the characteristics of a Seyfert 1. These broad lines were not present in the SDSS spectrum taken a decade earlier and faded away within 2 yr, as observed in several late-time MDM spectra. We argue that the dramatic appearance and disappearance of the broad lines and a factor of ∼8 increase in the optical continuum are most likely caused by variability in the pre-existing accretion disc than a tidal disruption event, supernova, or variable obscuration. The time-scale for the turn-on of the optical emission of ∼70 d observed in this transient is among the shortest observed in a 'changing-look' active galactic nucleus.