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Evidence for Late-stage Eruptive Mass-loss in the Progenitor to SN2018gep, a Broad-lined Ic Supernova: Pre-explosion Emission and a Rapidly Rising Luminous Transient

Ho, Anna Y. Q. and Goldstein, Daniel A. and Andreoni, Igor and De, Kishalay and Dugas, Alison and Kasliwal, Mansi M. and Kulkarni, S. R. and Walters, Richard and Yao, Yuhan and Dekany, Richard and Hale, David and Fremling, Christoffer and Graham, Matthew J. and Masci, Frank J. and Rusholme, Ben and Shupe, David L. (2019) Evidence for Late-stage Eruptive Mass-loss in the Progenitor to SN2018gep, a Broad-lined Ic Supernova: Pre-explosion Emission and a Rapidly Rising Luminous Transient. . (Unpublished)

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We present detailed observations of ZTF18abukavn (SN2018gep), discovered in high-cadence data from the Zwicky Transient Facility as a rapidly rising (1.4±0.1 mag/hr) and luminous (M_(g,peak) = −20 mag) transient. It is spectroscopically classified as a broad-lined stripped-envelope supernova (Ic-BL SN). The high peak luminosity (L_(bol) ≳ 3×10^(44) erg sec^(−1)), the short rise time (t_(rise) = 3 days in g-band), and the blue colors at peak (g−r ∼ −0.4) all resemble the high-redshift Ic-BL iPTF16asu, as well as several other unclassified fast transients. The early discovery of SN2018gep (within an hour of shock breakout) enabled an intensive spectroscopic campaign, including the highest-temperature (T_(eff) ≳ 40,000 K) spectra of a stripped-envelope SN. A retrospective search revealed luminous (M_g ∼ M_r ≈ −14mag) emission in the days to weeks before explosion, the first definitive detection of precursor emission for a Ic-BL. We find a limit on the isotropic gamma-ray energy release E_(γ,iso) < 4.9×10^(48) erg, a limit on X-ray emission L_X < 10^(40) erg sec^(−1), and a limit on radio emission νL_ν ≲ 10^(37) erg sec^(−1). Taken together, we find that the early (<10days) data are best explained by shock breakout in a massive shell of dense circumstellar material (0.02M⊙) at large radii (3×10^(14)cm) that was ejected in eruptive pre-explosion mass-loss episodes. The late-time (>10 days) light curve requires an additional energy source, which could be the radioactive decay of Ni-56.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper
Ho, Anna Y. Q.0000-0002-9017-3567
Goldstein, Daniel A.0000-0003-3461-8661
Andreoni, Igor0000-0002-8977-1498
De, Kishalay0000-0002-8989-0542
Kasliwal, Mansi M.0000-0002-5619-4938
Kulkarni, S. R.0000-0001-5390-8563
Yao, Yuhan0000-0001-6747-8509
Fremling, Christoffer0000-0002-4223-103X
Graham, Matthew J.0000-0002-3168-0139
Masci, Frank J.0000-0002-8532-9395
Rusholme, Ben0000-0001-7648-4142
Shupe, David L.0000-0003-4401-0430
Additional Information:Received May 2019; Revised 12 June 2019. The authors would like to thank the anonymous referee whose comments improved the flow, precision, and clarify of the paper. It is a pleasure to thank Tony Piro, Dan Kasen, E. Sterl Phinney, Eliot Quataert, Maryam Modjaz, Jim Fuller, Lars Bildsten, Udi Nakar, Paul Duffell, and Luc Dessart for helpful discussions. A.Y.Q.H. is particularly grateful to Tony Piro and the community at Carnegie Observatories for their hospitality on Tuesdays during the period in which this work was performed. Thank you to the staff at the SMA, AMI, the VLA, Swift, and Chandra for rapidly scheduling and executing the observations. Thank you to David Palmer (LANL) for his assistance in searching the pointing data for Swift/BAT. Thank you to Michael J. Koss (Eureka Scientific Int), Andrew Drake (Caltech), Scott Adams (Caltech), Matt Hankins (Caltech), Kevin Burdge (Caltech), and Kirsty Taggart (LJMU) for assisting with optical spectroscopic observations. Thank you to Erik Petigura and David Hogg for their advice on figure aesthetics. Thank you to David Alexander Kann (IAA-CSIC) for pointing out an error in an early version of the paper posted to the arXiv. D.A.G. thanks Stefan van der Walt and Ari Crellin-Quick for assistance with skyportal, which enabled the search for pre-explosion emission. A.Y.Q.H. is supported by a National Science Foundation Graduate Research Fellowship under Grant No. DGE1144469. This work was supported by the GROWTH project funded by the National Science Foundation under PIRE Grant No. 1545949. A.G.-Y. is supported by the EU via ERC grant No. 725161, the ISF, the BSF Transformative program and by a Kimmel award. Y.T. studied as a GROWTH intern at Caltech during the summer and fall of 2017. C.C.N. thanks the funding from MOST grant 104-2923-M-008 -004-MY5. R.L. is supported by a Marie Sklodowska-Curie Individual Fellowship within the Horizon 2020 European Union (EU) Framework Programme for Research and Innovation (H2020-MSCA-IF-2017-794467). A.H. acknowledges support by the I-Core Program of the Planning and Budgeting Committee and the Israel Science Foundation, and support by the ISF grant 647/18. This research was supported by a Grant from the GIF, the German-Israeli Foundation for Scientific Research and Development. This research was funded in part by the Gordon and Betty Moore Foundation through Grant GBMF5076, and a grant from the Heising-Simons Foundation. A.C. acknowledges support from the NSF CAREER award N. 1455090 and from the NASA/Chandra GI award N. GO8-19055A. Research support to I.A. is provided by the GROWTH project, funded by the National Science Foundation under Grant No 1545949. 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. Major funding has been provided by the U.S National Science Foundation under Grant No. AST-1440341 and by the ZTF partner institutions: the California Institute of Technology, the Oskar Klein Centre, the Weizmann Institute of Science, the University of Maryland, the University of Washington, Deutsches Elektronen-Synchrotron, the University of Wisconsin-Milwaukee, and the TANGO Program of the University System of Taiwan. Partially based on observations made with the Nordic Optical Telescope, operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias. The Liverpool Telescope is operated by Liverpool John Moores University with financial support from the UK Science and Technology Facilities Council. LT is located on the island of La Palma, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. The scientific results reported in this article are based in part on observations made by the Chandra X-ray Observatory. The data presented here were obtained in part with ALFOSC, which is provided by the Instituto de Astrofisica de Andalucia (IAA) under a joint agreement with the University of Copenhagen and NOTSA. The Submillimeter Array is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academia Sinica. We acknowledge the support of the staff of the Xinglong 2.16-m telescope. This work is supported by the National Natural Science Foundation of China (NSFC grants 11325313 and 11633002), and the National Program on Key Research and Development Project (grant no. 2016YFA0400803). SED Machine is based upon work supported by the National Science Foundation under Grant No. 1106171. This publication has made use of data collected at Lulin Observatory, partly supported by MoST grant 105-2112-M-008-024-MY3. The JEKYLL simulations were performed on resources provided by the Swedish National Infrastructure for Computing (SNIC) at Parallelldatorcentrum (PDC). Software: Astropy (Astropy Collaboration et al. 2013,2018),IPython(P_erez&Granger2007),matplotlib (Hunter 2007), numpy (Oliphant 2006), scipy (Jones et al. 2001), extinction (Barbary et al. 2016) SkyPortal (van derWalt et al. 2019) Facilities: CFHT, Keck:I (LRIS), Hale (DBSP), AMI, Liverpool:2m (IO:O, SPRAT), DCT, Swift (UVOT, XRT), Beijing:2.16m, EVLA, SMA, LO:1m, NOT (ALFOSC)
Group:Infrared Processing and Analysis Center (IPAC), Zwicky Transient Facility
Funding AgencyGrant Number
NSF Graduate Research FellowshipDGE-1144469
European Research Council (ERC)725161
Binational Science Foundation (USA-Israel)UNSPECIFIED
Ministry of Science and Technology (Taipei)104-2923-M-008-004-MY5
Marie Curie Fellowship794467
I-CORE Program of the Planning and Budgeting CommitteeUNSPECIFIED
Israel Science Foundation647/18
German-Israeli Foundation for Research and DevelopmentUNSPECIFIED
Gordon and Betty Moore FoundationGBMF5076
Heising-Simons FoundationUNSPECIFIED
Oskar Klein CentreUNSPECIFIED
Weizmann Institute of ScienceUNSPECIFIED
University of MarylandUNSPECIFIED
University of WashingtonUNSPECIFIED
Deutsches Elektronen-SynchrotronUNSPECIFIED
University of Wisconsin-MilwaukeeUNSPECIFIED
University System of TaiwanUNSPECIFIED
Science and Technology Facilities Council (STFC)UNSPECIFIED
Smithsonian InstitutionUNSPECIFIED
Academia SinicaUNSPECIFIED
National Natural Science Foundation of China11325313
National Natural Science Foundation of China11633002
National Program on Key Research and Development Project2016YFA0400803
Ministry of Science and Technology (Taipei)105-2112-M-008-024-MY3
ZTF partner institutionsUNSPECIFIED
Subject Keywords:shock waves, methods: observational, stars: mass-loss, (stars:) supernovae: general, (stars:) supernovae: individual (SN2018gep)
Record Number:CaltechAUTHORS:20191002-100608633
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:99014
Deposited By: Tony Diaz
Deposited On:02 Oct 2019 17:34
Last Modified:03 Oct 2019 21:46

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