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A Family Tree of Optical Transients from Narrow-Line Seyfert 1 Galaxies

Frederick, Sara and Gezari, Suvi and Graham, Matthew J. and Sollerman, Jesper and van Velzen, Sjoert and Perley, Daniel A. and Stern, Daniel and Ward, Charlotte and Hammerstein, Erica and Hung, Tiara and Yan, Lin and Andreoni, Igor and Bellm, Eric C. and Duev, Dmitry A. and Kowalski, Marek and Mahabal, Ashish A. and Masci, Frank J. and Medford, Michael and Rusholme, Ben and Walters, Richard (2020) A Family Tree of Optical Transients from Narrow-Line Seyfert 1 Galaxies. . (Unpublished) https://resolver.caltech.edu/CaltechAUTHORS:20210205-093228545

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Abstract

The Zwicky Transient Facility (ZTF) has discovered five new events belonging to an emerging class of AGN undergoing smooth flares with large amplitudes and rapid rise times. This sample consists of several transients that were initially classified as supernovae with narrow spectral lines. However, upon closer inspection, all of the host galaxies display resolved Balmer lines characteristic of a narrow-line Seyfert 1 (NLSy1) galaxy. The transient events are long-lived, over 400 days on average. We report UV and X-ray follow-up of the flares and observe persistent UV-bright emission, with two of the five transients detected with luminous X-ray emission, ruling out a supernova interpretation. We compare the properties of this sample to previously reported flaring NLSy1 galaxies, and find that they fall into three spectroscopic categories: Transients with 1) Balmer line profiles and Fe II complexes typical of NLSy1s, 2) strong He II profiles, and 3) He II profiles including Bowen fluorescence features. The latter are members of the growing class of AGN flares attributed to enhanced accretion reported by Trakhtenbrot et al. (2019). We consider physical interpretations in the context of related transients from the literature. For example, two of the sources show high amplitude rebrightening in the optical, ruling out a simple tidal disruption event scenario for those transients. We conclude that three of the sample belong to the Trakhtenbrot et al. (2019) class, and two are TDEs in NLSy1s. We also aim to understand why NLSy1s are preferentially the sites of such rapid enhanced flaring activity.


Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription
http://arxiv.org/abs/2010.08554arXivDiscussion Paper
ORCID:
AuthorORCID
Frederick, Sara0000-0001-9676-730X
Gezari, Suvi0000-0003-3703-5154
Graham, Matthew J.0000-0002-3168-0139
Sollerman, Jesper0000-0003-1546-6615
van Velzen, Sjoert0000-0002-3859-8074
Perley, Daniel A.0000-0001-8472-1996
Stern, Daniel0000-0003-2686-9241
Ward, Charlotte0000-0002-4557-6682
Hammerstein, Erica0000-0002-5698-8703
Hung, Tiara0000-0002-9878-7889
Yan, Lin0000-0003-1710-9339
Andreoni, Igor0000-0002-8977-1498
Bellm, Eric C.0000-0001-8018-5348
Duev, Dmitry A.0000-0001-5060-8733
Kowalski, Marek0000-0001-8594-8666
Mahabal, Ashish A.0000-0003-2242-0244
Masci, Frank J.0000-0002-8532-9395
Medford, Michael0000-0002-7226-0659
Rusholme, Ben0000-0001-7648-4142
Walters, Richard0000-0002-1835-6078
Additional Information:We would like to thank A. Dittman for useful comments. S. Gezari is supported in part by NSF CAREER grant 1454816. We thank C. Barbarino for reducing the Nordic Optical Telescope observation of ZTF19aatubsj. We thank R. Foley for contributing the Lick Shane Kast observation of ZTF19abvgxrq. Based on observations obtained with the Samuel Oschin Telescope 48-inch and the 60-inch Telescope at the Palomar Observatory as part of the Zwicky Transient Facility project. ZTF is supported by the National Science Foundation under Grant No. AST-1440341 and a collaboration including Caltech, IPAC, the Weizmann Institute for Science, the Oskar Klein Center at Stockholm University, the University of Maryland, the University of Washington, Deutsches Elektronen-Synchrotron and Humboldt University, Los Alamos National Laboratories, the TANGO Consortium of Taiwan, the University of Wisconsin at Milwaukee, and Lawrence Berkeley National Laboratories. Operations are conducted by COO, IPAC, and UW. This work was supported by the GROWTH project funded by the National Science Foundation under Grant No 1545949. The SED Machine is based upon work supported by the National Science Foundation under Grant No. 1106171. The ZTF forced-photometry service was funded under the Heising-Simons Foundation Grant No. 12540303 (PI: Graham). These results made use of the Discovery Channel Telescope at Lowell Observatory. Lowell is a private, non-pro�fit 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 upgrade of the DeVeny optical spectrograph has been funded by a generous grant from John and Ginger Giovale. Based on observations made with the Nordic Optical Telescope, owned in collaboration by the University of Turku and Aarhus University, and operated jointly by Aarhus University, the University of Turku and the University of Oslo, representing Denmark, Finland and Norway, the University of Iceland and Stockholm University at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astro�fisica de Canarias. This research has made use of data obtained through the High Energy Astrophysics Science Archive Research Center Online Service, provided by the NASA/Goddard Space Flight Center. We acknowledge the use of public data from the Swift data archive. Facilities: PO:1.2m, PO:1.5m, Hale, Swift(XRT and UVOT), DCT, NOT, Shane, Liverpool:2m Software: Pyraf,Lm�t,HEAsoft,PIMMS
Group:Infrared Processing and Analysis Center (IPAC), Zwicky Transient Facility
Funders:
Funding AgencyGrant Number
NSFAST-1454816
NSFAST-1440341
ZTF partner institutionsUNSPECIFIED
NSFOISE-1545949
NSFAST-1106171
Heising-Simons Foundation12540303
John and Ginger GiovaleUNSPECIFIED
Subject Keywords:accretion, accretion disks | galaxies: active | galaxies: nuclei | quasars: emission lines | relativistic processes | surveys
Record Number:CaltechAUTHORS:20210205-093228545
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20210205-093228545
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:107931
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:05 Feb 2021 23:00
Last Modified:05 Feb 2021 23:00

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