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iPTF Discovery of the Rapid “Turn-on” of a Luminous Quasar

Gezari, S. and Hung, T. and Cenko, S. B. and Blagorodnova, N. and Yan, Lin and Kulkarni, S. R. and Mooley, K. and Kong, A. K. H. and Cantwell, T. M. and Yu, P. C. and Cao, Y. and Fremling, C. and Neill, J. D. and Ngeow, C.-C. and Nugent, P. E. and Wozniak, P. (2017) iPTF Discovery of the Rapid “Turn-on” of a Luminous Quasar. Astrophysical Journal, 835 (2). Art. No. 144. ISSN 0004-637X.

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We present a radio-quiet quasar at z = 0.237 discovered "turning on" by the intermediate Palomar Transient Factory (iPTF). The transient, iPTF 16bco, was detected by iPTF in the nucleus of a galaxy with an archival Sloan Digital Sky Survey spectrum with weak narrow-line emission characteristic of a low-ionization nuclear emission-line region (LINER). Our follow-up spectra show the dramatic appearance of broad Balmer lines and a power-law continuum characteristic of a luminous (L_(bol) ≈ 10^(45) erg s^(−1)) type 1 quasar 12 yr later. Our photometric monitoring with PTF from 2009–2012 and serendipitous X-ray observations from the XMM-Newton Slew Survey in 2011 and 2015 constrain the change of state to have occurred less than 500 days before the iPTF detection. An enhanced broad Hα/[O III] λ5007 line ratio in the type 1 state relative to other changing-look quasars also is suggestive of the most rapid change of state yet observed in a quasar. We argue that the >10 increase in Eddington ratio inferred from the brightening in UV and X-ray continuum flux is more likely due to an intrinsic change in the accretion rate of a preexisting accretion disk than an external mechanism such as variable obscuration, microlensing, or the tidal disruption of a star. However, further monitoring will be helpful in better constraining the mechanism driving this change of state. The rapid "turn-on" of the quasar is much shorter than the viscous infall timescale of an accretion disk and requires a disk instability that can develop around a ~ 10^8 M_⊙ black hole on timescales less than 1 yr.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Gezari, S.0000-0003-3703-5154
Cenko, S. B.0000-0003-1673-970X
Blagorodnova, N.0000-0003-0901-1606
Yan, Lin0000-0003-1710-9339
Kulkarni, S. R.0000-0001-5390-8563
Mooley, K.0000-0002-2557-5180
Kong, A. K. H.0000-0002-5105-344X
Yu, P. C.0000-0001-8894-0854
Cao, Y.0000-0002-8036-8491
Fremling, C.0000-0002-4223-103X
Neill, J. D.0000-0002-0466-1119
Ngeow, C.-C.0000-0001-8771-7554
Nugent, P. E.0000-0002-3389-0586
Wozniak, P.0000-0002-9919-3310
Additional Information:© 2017 The American Astronomical Society. Received 2016 November 4; revised 2016 December 13; accepted 2016 December 13; published 2017 January 24. We thank the anonymous referee for their helpful comments that improved the manuscript. S.G. is supported in part by NSF CAREER grant 1454816 and NASA Swift Cycle 12 grant NNX16AN85G. S.G. thanks Mike Koss for help with the X-ray data archives. These results made use of the Discovery Channel Telescope at Lowell Observatory. Lowell is a private, non-profit institution dedicated to astrophysical research and public appreciation of astronomy and operates the DCT in partnership with Boston University, the University of Maryland, the University of Toledo, Northern Arizona University, and Yale University. The W. M. Keck Observatory is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA; the Observatory was made possible by the generous financial support of the W. M. Keck Foundation. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. K.M.'s research is supported by the Oxford Centre for Astrophysical Surveys, which is funded through generous support from the Hintze Family Charitable Foundation. The AMI telescope gratefully acknowledges support from the European Research Council under grant ERC-2012- StG-307215 LODESTONE, the UK Science and Technology Facilities Council (STFC), and the University of Cambridge. We thank the AMI staff for scheduling the observations.
Group:Infrared Processing and Analysis Center (IPAC), Palomar Transient Factory, Space Astrophysics Laboratory, Astronomy Department
Funding AgencyGrant Number
W. M. Keck FoundationUNSPECIFIED
Department of Energy (DOE)DE-AC02-05CH11231
Oxford Centre for Astrophysical SurveysUNSPECIFIED
Hintze Family Charitable FoundationUNSPECIFIED
European Research Council (ERC)307215
Science and Technology Facilities Council (STFC)UNSPECIFIED
University of CambridgeUNSPECIFIED
Subject Keywords:accretion, accretion disks – black hole physics – galaxies: active – surveys
Issue or Number:2
Record Number:CaltechAUTHORS:20170127-143119431
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:73787
Deposited By: Tony Diaz
Deposited On:27 Jan 2017 22:54
Last Modified:09 Mar 2020 13:19

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