A Transient “Changing-look” Active Galactic Nucleus Resolved on Month Timescales from First-year Sloan Digital Sky Survey V Data

Zeltyn, Grisha and Trakhtenbrot, Benny and Eracleous, Michael and Runnoe, Jessie and Trump, Jonathan R. and Stern, Jonathan and Shen, Yue and Hernández-García, Lorena and Bauer, Franz E. and Yang, Qian and Dwelly, Tom and Ricci, Claudio and Green, Paul and Anderson, Scott F. and Assef, Roberto J. and Guolo, Muryel and MacLeod, Chelsea and Davis, Megan C. and Fries, Logan and Gezari, Suvi and Grogin, Norman A. and Homan, David and Koekemoer, Anton M. and Krumpe, Mirko and LaMassa, Stephanie and Liu, Xin and Merloni, Andrea and Martínez-Aldama, Mary Loli and Schneider, Donald P. and Temple, Matthew J. and Brownstein, Joel R. and Ibarra-Medel, Hector and Burke, Jamison and Pellegrino, Craig and Kollmeier, Juna A. (2022) A Transient “Changing-look” Active Galactic Nucleus Resolved on Month Timescales from First-year Sloan Digital Sky Survey V Data. The Astrophysical Journal Letters, 939 (1). L16. ISSN 2041-8205

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We 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.

Item Type: Article
Subjects: Eprints STM archive > Physics and Astronomy
Depositing User: Unnamed user with email admin@eprints.stmarchive
Date Deposited: 05 May 2023 12:01
Last Modified: 02 Jan 2024 13:06
URI: http://public.paper4promo.com/id/eprint/161

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