A Mid-IR Selected Changing-look Quasar and Physical Scenarios for Abrupt AGN Fading
We report a new changing-look quasar, WISE J105203.55+151929.5 at z = 0.303, found by identifying highly mid-IR-variable quasars in the Wide-field Infrared Survey Explorer (WISE)/Near-Earth Object WISE Reactivation (NEOWISE) data stream. Compared to multiepoch mid-IR photometry of a large sample of SDSS-confirmed quasars, WISE J1052+1519 is an extreme photometric outlier, fading by more than a factor of two at 3.4 and 4.6 μm since 2009. Swift target-of-opportunity observations in 2017 show even stronger fading in the soft X-rays compared to the ROSAT detection of this source in 1995, with at least a factor of 15 decrease. We obtained second-epoch spectroscopy with the Palomar telescope in 2017 that, when compared with the 2006 archival SDSS spectrum, reveals that the broad Hβ emission has vanished and that the quasar has become significantly redder. The two most likely interpretations for this dramatic change are source fading or obscuration, where the latter is strongly disfavored by the mid-IR data. We discuss various physical scenarios that could cause such changes in the quasar luminosity over this timescale, and favor changes in the innermost regions of the accretion disk that occur on the thermal and heating/cooling front timescales. We discuss possible physical triggers that could cause these changes, and predict the multiwavelength signatures that could distinguish these physical scenarios.
Additional Information© 2018. The American Astronomical Society. Received 2018 March 5; revised 2018 May 17; accepted 2018 May 20; published 2018 August 27. We thank the anonymous referee for a timely and informative report, which has improved our manuscript. We also thank Javier García for useful comments on the manuscript and Nikita Kamraj for assisting with the 2017 January Palomar observations. This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. This publication makes use of data products from the Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE), which is a project of the Jet Propulsion Laboratory/California Institute of Technology. NEOWISE is funded by the National Aeronautics and Space Administration. C.R.T.S. was supported by the NSF grants AST-1313422, AST-1413600, and AST-1518308. D.S. acknowledges support from NASA through ADAP award 12-ADAP12-0109. B.M. and K.E.S.F. are supported by NSF PAARE AST-1153335, and with to thank JPL and Caltech for support during their sabbatical in early 2017. M.J.G., S.G.D., and A.J.D. acknowledge partial support from the NASA grant 16-ADAP16-0232, and NSF grants AST-1413600 and AST-1518308. N.P.R. acknowledges support from the STFC and the Ernest Rutherford Fellowship. A.M.M. acknowledges support from NASA through ADAP award NNH17AE75I. R.J.A. acknowledges support from FONDECYT grant number 1151408. M.B. gratefully acknowledges financial support from NASA Headquarters under the NASA Earth and Space Science Fellowship Program, grant NNX14AQ07H, and the support from the black hole Initiative at Harvard University, which is funded by a grant from the John Templeton Foundation. A.D.'s research was supported in part by the National Optical Astronomy Observatory (NOAO). NOAO is operated by the Association of Universities for Research in Astronomy (AURA), Inc. under a cooperative agreement with the National Science Foundation. H.D.J. acknowledges support from the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education (NRF-2017R1A6A3A04005158). Facilities: SO:1.5 m - , Blanco, Hale - , PS1 - , Sloan - , WISE. -
Published - Stern_2018_ApJ_864_27.pdf
Accepted Version - 1805.06920