Zeltyn G.Trakhtenbrot B.Eracleous M.Runnoe J.Trump J.R.Stern J.Shen Y.Hernández-García L.Bauer F.E.Yang Q.Dwelly T.Ricci C.Green P.Anderson S.F.Assef R.J.Guolo M.MacLeod C.Davis M.C.Fries L.Gezari S.Grogin N.A.Homan D.Koekemoer A.M.Krumpe M.LaMassa S.Liu X.Merloni A.Martínez-Aldama M.L.Schneider D.P.Temple M.J.Brownstein J.R.Ibarra-Medel H.Burke J.Pellegrino C.Kollmeier J.A.2025-03-142025-03-142022https://hdl.handle.net/20.500.12740/17152We report the discovery of a new “changing-look” active galactic nucleus (CLAGN) event, in the quasar SDSS J162829.17+432948.5 at z = 0.2603, identified through repeat spectroscopy from the fifth Sloan Digital Sky Survey (SDSS-V). Optical photometry taken during 2020-2021 shows a dramatic dimming of Δg ≈ 1 mag, followed by a rapid recovery on a timescale of several months, with the ≲2 month period of rebrightening captured in new SDSS-V and Las Cumbres Observatory spectroscopy. This is one of the fastest CLAGN transitions observed to date. Archival observations suggest that the object experienced a much more gradual dimming over the period of 2011-2013. Our spectroscopy shows that the photometric changes were accompanied by dramatic variations in the quasar-like continuum and broad-line emission. The excellent agreement between the pre- and postdip photometric and spectroscopic appearances of the source, as well as the fact that the dimmest spectra can be reproduced by applying a single extinction law to the brighter spectral states, favor a variable line-of-sight obscuration as the driver of the observed transitions. Such an interpretation faces several theoretical challenges, and thus an alternative accretion-driven scenario cannot be excluded. The recent events observed in this quasar highlight the importance of spectroscopic monitoring of large active galactic nucleus samples on weeks-to-months timescales, which the SDSS-V is designed to achieve. © 2022. The Author(s). Published by the American Astronomical Society.PDFArtículohttp://dx.doi.org/10.3847/2041-8213/ac9a47