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Helium-rich Superluminous Supernovae from the Zwicky Transient Facility

Yan, Lin and Perley, D. and Schulze, S. and Lunnan, R. and Sollerman, J. and De, K. and Chen, Z. and Fremling, C. and Gal-Yam, A. and Taggart, K. and Chen, T. W. and Andreoni, I. and Bellm, E. C. and Cunningham, V. and Dekany, R. and Duev, D. and Fransson, C. and Laher, R. and Hankins, M. and Ho, A. Y. Q. and Jencson, J. and Kaye, S. and Kulkarni, S. and Kasliwal, M. and Golkhou, V. and Graham, M. and Masci, F. and Miller, A. and Neill, J. and Ofek, E. and Porter, M. and Mróz, P. and Reiley, D. and Riddle, R. and Rigault, M. and Rusholme, B. and Shupe, D. and Soumagnac, M. and Smith, R. and Tartaglia, L. and Yao, Y. and Yaron, O. (2020) Helium-rich Superluminous Supernovae from the Zwicky Transient Facility. Astrophysical Journal Letters, 902 (1). Art. No. L8. ISSN 2041-8213.

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Helium is expected to be present in the massive ejecta of some hydrogen-poor superluminous supernovae (SLSN-I). However, until now only one event has been identified with He features in its photospheric spectra (PTF10hgi). We present the discovery of a new He-rich SLSN-I, ZTF19aawfbtg (SN2019hge), at z = 0.0866. This event has more than 10 optical spectra at phases from −41 to +103 days relative to the peak, most of which match well with that of PTF10hgi. Confirmation comes from a near-IR spectrum taken at +34 days, revealing He I features with P-Cygni profiles at 1.083 and 2.058 μm. Using the optical spectra of PTF10hgi and SN2019hge as templates, we examined 70 other SLSNe-I discovered by Zwicky Transient Facility in the first two years of operation and found five additional SLSNe-I with distinct He-features. The excitation of He I atoms in normal core-collapse supernovae requires nonthermal radiation, as proposed by previous studies. These He-rich events cannot be explained by the traditional ⁵⁶Ni mixing model because of their blue spectra, high peak luminosities, and long rise timescales. Magnetar models offer a possible solution since pulsar winds naturally generate high-energy particles, potential sources of nonthermal excitation. An alternative model is the interaction between the ejecta and dense H-poor circumstellar material, which may be supported by observed undulations in the light curves. These six SLSNe-Ib have relatively low-peak luminosities (rest frame M_g = −20.06 ± 0.16).

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Yan, Lin0000-0003-1710-9339
Perley, D.0000-0001-8472-1996
Schulze, S.0000-0001-6797-1889
Lunnan, R.0000-0001-9454-4639
Sollerman, J.0000-0003-1546-6615
De, K.0000-0002-8989-0542
Fremling, C.0000-0002-4223-103X
Gal-Yam, A.0000-0002-3653-5598
Taggart, K.0000-0002-5748-4558
Chen, T. W.0000-0002-1066-6098
Andreoni, I.0000-0002-8977-1498
Bellm, E. C.0000-0001-8018-5348
Cunningham, V.0000-0003-2292-0441
Dekany, R.0000-0002-5884-7867
Duev, D.0000-0001-5060-8733
Fransson, C.0000-0001-8532-3594
Laher, R.0000-0003-2451-5482
Hankins, M.0000-0001-9315-8437
Ho, A. Y. Q.0000-0002-9017-3567
Jencson, J.0000-0001-5754-4007
Kulkarni, S.0000-0001-5390-8563
Kasliwal, M.0000-0002-5619-4938
Golkhou, V.0000-0001-8205-2506
Graham, M.0000-0002-3168-0139
Masci, F.0000-0002-8532-9395
Miller, A.0000-0001-9515-478X
Neill, J.0000-0002-0466-1119
Ofek, E.0000-0002-6786-8774
Porter, M.0000-0003-3168-5586
Mróz, P.0000-0001-7016-1692
Riddle, R.0000-0002-0387-370X
Rigault, M.0000-0002-8121-2560
Rusholme, B.0000-0001-7648-4142
Shupe, D.0000-0003-4401-0430
Soumagnac, M.0000-0001-6753-1488
Smith, R.0000-0001-7062-9726
Tartaglia, L.0000-0003-3433-1492
Yao, Y.0000-0001-6747-8509
Yaron, O.0000-0002-0301-8017
Additional Information:© 2020 The American Astronomical Society. Received 2020 June 23; revised 2020 August 19; accepted 2020 August 23; published 2020 October 7. 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. The Liverpool Telescope is operated on the island of La Palma by Liverpool John Moores University in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias with financial support from the UK Science and Technology Facilities Council. 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 #12540303 (PI: Graham). This work uses the GROWTH Followup Marshal (Kasliwal et al. 2019) and was supported by the GROWTH project funded by the National Science Foundation under grant No. 1545949. A.A.M. is funded by the Large Synoptic Survey Telescope Corporation, the Brinson Foundation, and the Moore Foundation in support of the LSSTC Data Science Fellowship Program; he also receives support as a CIERA Fellow by the CIERA Postdoctoral Fellowship Program (Center for Interdisciplinary Exploration and Research in Astrophysics, Northwestern University). R.L. is supported by a Marie Skłodowska-Curie Individual Fellowship within the Horizon 2020 European Union (EU) Framework Programme for Research and Innovation (H2020-MSCA-IF-2017-794467).
Group:Astronomy Department, Infrared Processing and Analysis Center (IPAC), Zwicky Transient Facility
Funding AgencyGrant Number
ZTF partner institutionsUNSPECIFIED
Science and Technology Facilities Council (STFC)UNSPECIFIED
Heising-Simons Foundation12540303
Large Synoptic Survey Telescope CorporationUNSPECIFIED
Brinson FoundationUNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA)UNSPECIFIED
Northwestern UniversityUNSPECIFIED
Marie Curie FellowshipH2020-MSCA-IF-2017-794467
Subject Keywords:Supernovae ; Type Ib supernovae
Issue or Number:1
Classification Code:Unified Astronomy Thesaurus concepts: Supernovae (1668); Type Ib supernovae (1729)
Record Number:CaltechAUTHORS:20200825-092934011
Persistent URL:
Official Citation:Lin Yan et al 2020 ApJL 902 L8
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105097
Deposited By: Tony Diaz
Deposited On:25 Aug 2020 17:03
Last Modified:07 Oct 2020 21:38

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