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

Abstract

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 $\Delta$g$\approx$1 mag, followed by a rapid recovery on a timescale of several months, with the $\lesssim$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.

arXiv commentPublished in ApJL

References in corpus (49)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Array Programming with NumPy
• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• The Sloan Digital Sky Survey: Technical Summary
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• The 2.5 m Telescope of the Sloan Digital Sky Survey
• A Catalog of Quasar Properties from SDSS DR7
• The Zwicky Transient Facility: Data Processing, Products, and Archive
• Las Cumbres Observatory Global Telescope Network
• The Multi-Object, Fiber-Fed Spectrographs for SDSS and the Baryon Oscillation Spectroscopic Survey
• The Low-Luminosity End of the Radius-Luminosity Relationship for Active Galactic Nuclei
• The Pan-STARRS1 Database and Data Products
• The Discovery of the First "Changing Look" Quasar: New Insights into the Physics & Phenomenology of AGN
• Dust in active nuclei. I. Evidence for "anomalous" properties
• Red and Reddened Quasars in the Sloan Digital Sky Survey
• Ubiquitous variability of X-ray absorbing column densities in Seyfert 2 Galaxies
• The Mass Function of Active Black Holes in the Local Universe
• Extreme X-ray spectral variability in the Seyfert 2 Galaxy NGC 1365
• The Dust Attenuation Law in Galaxies
• Reverberation Measurements of the Inner Radius of the Dust Torus in 17 Seyfert Galaxies
• First X-ray-Based Statistical Tests for Clumpy-Torus Models: Eclipse Events from 230 Years of Monitoring of Seyfert AGN
• Discovery of 21 New Changing-look AGNs in Northern Sky
• The Lick AGN Monitoring Project 2011: Spectroscopic Campaign and Emission-Line Light Curves
• The Automatic Learning for the Rapid Classification of Events (ALeRCE) Alert Broker
• 1ES 1927+654: An AGN Caught Changing Look on a Timescale of Months
• The Sloan Digital Sky Survey Reverberation Mapping Project: Sample Characterization
• A Mid-IR Selected Changing-Look Quasar and Physical Scenarios for Abrupt AGN Fading
• Changing-Look Quasar Candidates: First Results from Follow-up Spectroscopy of Highly Optically Variable Quasars
• Dust inflated accretion disc as the origin of the Broad Line Region in Active Galactic Nuclei
• Towards an Understanding of Changing-Look Quasars: An Archival Spectroscopic Search in SDSS
• "Comets" orbiting a black hole
• Mid-infrared variability of changing-look AGN
• iPTF Discovery of the Rapid "Turn On" of a Luminous Quasar
• Type 1 low z AGN. I. Emission properties
• The Toroidal Obscuration of Active Galactic Nuclei
• A New Class of Changing-Look LINERs
• BASS XXV: DR2 Broad-line Based Black Hole Mass Estimates and Biases from Obscuration
• The Sloan Digital Sky Survey Reverberation Mapping Project: How Broad Emission Line Widths Change When Luminosity Changes
• Magnetic flux inversion in a peculiar changing look AGN
• Rapid "Turn-on" of type 1 AGN in a quiescent early type galaxy SDSS1115+0544
• Dust Reverberation Mapping in Distant Quasars from Optical and Mid-Infrared Imaging Surveys
• Partial dust obscuration in active galactic nuclei as a cause of broad-line profile and lag variability, and apparent accretion disc inhomogeneities
• The first high-redshift changing-look quasars
• Silicate Dust in Active Galactic Nuclei
• The Eddington ratio-dependent changing look events in NGC 2992
• The X-ray variability of Seyfert 1.8/1.9 galaxies
• A Rapid and Large-Amplitude X-ray Dimming Event in a z ~ 2.6 Radio-Quiet Quasar
• The Optical Variability of SDSS Quasars from Multi-epoch Spectroscopy. III. A Sudden UV Cutoff in Quasar SDSS J2317+0005

Cited by in corpus (12)

• Exploring Changing-look Active Galactic Nuclei with the Sloan Digital Sky Survey V: First Year Results
• BASS XXXIX: Swift-BAT AGN with changing-look optical spectra
• Probing the Origin of Changing-look Quasar Transitions with Chandra
• Investigating Changing-Look Active Galactic Nuclei with Long-term Optical and X-Ray Observations
• Improving the selection of changing-look AGNs through multi-wavelength photometric variability
• Multiple Flares in the Changing-Look AGN NGC 5273
• BASS-XL: X-ray variability properties of unobscured Active Galactic Nuclei
• Modeling Star Formation Histories of Changing-Look AGN Host Galaxies with Prospector
• A Systematic Search for Active Galactic Nucleus Flares in ZTF Data Release 23
• Reprocessing Models for the Optical Light Curves of Hypervariable Quasars from the Sloan Digital Sky Survey Reverberation Mapping Project
• Identifying Changing-Look AGN Transitions in Light Curve Data with the Zwicky Transient Facility
• A magnetically-supported disk-corona model for Changing-Look AGN transitions