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Mid-infrared Flare of TDE Candidate PS16dtm: Dust Echo and Implications for the Spectral Evolution

Jiang, Ning and Wang, Tinggui and Yan, Lin and Xiao, Ting and Yang, Chenwei and Dou, Liming and Wang, Huiyuan and Cutri, Roc and Mainzer, Amy (2017) Mid-infrared Flare of TDE Candidate PS16dtm: Dust Echo and Implications for the Spectral Evolution. Astrophysical Journal, 850 (1). Art. No. 63. ISSN 1538-4357. doi:10.3847/1538-4357/aa93f5.

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PS16dtm was classified as a candidate tidal disruption event in a dwarf Seyfert 1 galaxy with a low-mass black hole (~10^6 M_⊙) and has presented various intriguing photometric and spectra characteristics. Using the archival Wide-field Infrared Survey Explorer and the newly released NEOWISE data, we found that PS16dtm is experiencing a mid-infrared (MIR) flare that started ~11 days before the first optical detection. Interpreting the MIR flare as a dust echo requires close pre-existing dust with a high covering factor and suggests that the optical flare may have brightened slowly for some time before it became bright detectable from the ground. More evidence is given at the later epochs. At the peak of the optical light curve, the new inner radius of the dust torus has grown to a much larger size (i.e., a factor of seven of the initial radius) due to the strong radiation field. At ~150 days after the first optical detection, the dust temperature has dropped well below the sublimation temperature. Other peculiar spectral features shown by PS16dtm are the transient, prominent Fe II emission lines and outflows indicated by broad absorption lines detected during the optical flare. Our model explains the enhanced Fe II emission from iron that is newly released from the evaporated dust. The observed broad absorption line outflow could be explained by accelerated gas in the dust torus due to the radiation pressure.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Jiang, Ning0000-0002-7152-3621
Wang, Tinggui0000-0002-1517-6792
Yan, Lin0000-0003-1710-9339
Yang, Chenwei0000-0003-4975-2433
Dou, Liming0000-0002-4757-8622
Wang, Huiyuan0000-0002-4911-6990
Cutri, Roc0000-0002-0077-2305
Additional Information:© 2017 The American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 2017 July 27; revised 2017 October 10; accepted 2017 October 12; published 2017 November 17. We thank the anonymous referee for a thorough report and many constructive comments that help us improve this work. We thank Subo Dong and Ben Shappee for kindly providing us the ASAS-SN data when we prepared the draft. We thank Nicholas Stone for his very nice and timely comments on the interpretation of the early MIR detection after the draft was posted on arXiv. This work is supported by the National Basic Research Program of China (grant No. 2015CB857005), NSFC (NSFC-116203021, NSFC-11421303, NSFC-11303008, and NSFC-11733001), Joint Research Fund in Astronomy (U1431229, U1531245, and U1731104) under cooperative agreement between the NSFC and the CAS and the Fundamental Research Funds for the Central Universities. This research 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 research also makes use of data products from NEOWISE-R, which is a project of the Jet Propulsion Laboratory/California Institute of Technology, funded by the Planetary Science Division of the National Aeronautics and Space Administration.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
National Basic Research Program of China2015CB857005
National Science Foundation of China116203021
National Science Foundation of China11421303
National Science Foundation of China11303008
National Science Foundation of China11733001
Joint Research Fund in AstronomyU1431229
Joint Research Fund in AstronomyU1531245
Joint Research Fund in AstronomyU1731104
Chinese Academy of SciencesUNSPECIFIED
Fundamental Research Funds for the Central UniversitiesUNSPECIFIED
Subject Keywords:galaxies: active – galaxies: individual (PS16dtm) – galaxies: nuclei
Issue or Number:1
Record Number:CaltechAUTHORS:20171121-091446299
Persistent URL:
Official Citation:Ning Jiang et al 2017 ApJ 850 63
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:83389
Deposited By: Tony Diaz
Deposited On:21 Nov 2017 17:29
Last Modified:15 Nov 2021 19:57

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