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The luminous and rapidly evolving SN 2018bcc: Clues toward the origin of Type Ibn SNe from the Zwicky Transient Facility

Karamehmetoglu, E. and Fransson, C. and Sollerman, J. and Tartaglia, L. and Taddia, F. and De, K. and Fremling, C. and Bagdasaryan, A. and Barbarino, C. and Bellm, E. C. and Dekaney, R. and Dugas, A. M. and Giomi, M. and Goobar, A. and Graham, M. and Ho, A. and Laher, R. R. and Masci, F. J. and Neill, J. D. and Perley, D. and Riddle, R. and Rusholme, B. and Soumagnac, M. T. (2019) The luminous and rapidly evolving SN 2018bcc: Clues toward the origin of Type Ibn SNe from the Zwicky Transient Facility. . (Unpublished)

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Context: Type Ibn supernovae (SNe) are rapidly-evolving and luminous (M_(R,peak) ∼−19) transients interacting with He-rich circumstellar material (CSM). SN 2018bcc, detected by the ZTF shortly after explosion, provides the best constraints on the shape of the rising lightcurve of a fast Type Ibn. Aims: We use the high-quality data set of SN 2018bcc to study observational signatures of the class. Additionally, the powering mechanism of SN 2018bcc offers insights into the debated progenitor connection of Type Ibn SNe. Methods: Well-constrained lightcurve properties obtained from empirical models are compared with the literature. We fit the pseudo-bolometric lightcurve with semi-analytical models powered by radioactive decay and CSM interaction. The line profiles and emissivity of the prominent He I lines are modeled to study the formation of P-Cygni profiles and to estimate CSM properties. Results: SN 2018bcc has a risetime to peak of 5.6^(+0.2)_(−0.1) days in the rest frame with a rising shape powerlaw index near 2, and seems to be a typical rapidly-evolving Type Ibn SN. The spectrum lacks signatures of SN-like ejecta and is dominated by over 15 He emission features at 20 days past peak, alongside Ca and Mg, all with V_(FWHM) ∼ 2000 km s⁻¹. The luminous and rapidly-evolving lightcurve can be powered by CSM interaction but not by the decay of radioactive ⁵⁶Ni. Modeling of the He I lines indicates a dense and optically thick CSM that can explain the P-Cygni profiles. Conclusions: Like other rapidly-evolving Type Ibn SNe, SN 2018bcc is a luminous transient with a rapid rise to peak powered by shock-interaction inside a dense and He-rich CSM. Its spectra do not support the existence of two Type Ibn spectral classes. We also note the remarkable observational match to pulsational pair instability (PPI) SN models.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper
Karamehmetoglu, E.0000-0001-6209-838X
Fransson, C.0000-0001-8532-3594
Sollerman, J.0000-0003-1546-6615
Tartaglia, L.0000-0003-3433-1492
Taddia, F.0000-0002-2387-6801
De, K.0000-0002-8989-0542
Fremling, C.0000-0002-4223-103X
Barbarino, C.0000-0002-3821-6144
Bellm, E. C.0000-0001-8018-5348
Goobar, A.0000-0002-4163-4996
Graham, M.0000-0002-3168-0139
Ho, A.0000-0002-9017-3567
Laher, R. R.0000-0003-2451-5482
Masci, F. J.0000-0002-8532-9395
Neill, J. D.0000-0002-0466-1119
Perley, D.0000-0001-8472-1996
Riddle, R.0000-0002-0387-370X
Rusholme, B.0000-0001-7648-4142
Additional Information:© 2019 ESO. We gratefully acknowledge support from the Knut and Alice Wallenberg Foundation and the Swedish Research Council. 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. The Oskar Klein Centre is funded by the Swedish Research Council. This research is partially based on observations made with the Nordic Optical Telescope, operated by NOTSA at IAC using ALFOSC, which is provided by the IAA. Some of the data presented herein were obtained at the W.M. Keck Observatory, which 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. Some of the data presented herein were obtained with the Liverpool Telescope 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. This work is partly based on observations made with DOLoRes@TNG. This research made use of Astropy, a community-developed core Python package for Astronomy (Astropy Collaboration, 2018) IRAF, is distributed by the National Optical Astronomy Observatories, which are operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation. The python version which was used, PyRAF, is a product of the Space Telescope Science Institute, which is operated by AURA for NASA. SED Machine is based upon work supported by the National Science Foundation under Grant No. 1106171. We would like to thank E. Ofek for his comments on the manuscript.
Group:Infrared Processing and Analysis Center (IPAC), Zwicky Transient Facility
Funding AgencyGrant Number
Knut and Alice Wallenberg FoundationUNSPECIFIED
Swedish Research CouncilUNSPECIFIED
Oskar Klein CentreUNSPECIFIED
Stockholm UniversityUNSPECIFIED
Weizmann Institute of ScienceUNSPECIFIED
University of MarylandUNSPECIFIED
University of WashingtonUNSPECIFIED
Deutsches Elektronen-SynchrotronUNSPECIFIED
University of Wisconsin-MilwaukeeUNSPECIFIED
University System of TaiwanUNSPECIFIED
W. M. Keck FoundationUNSPECIFIED
Science and Technology Facilities Council (STFC)UNSPECIFIED
Subject Keywords:supernovae: general – supernovae: individual: SN 2018bcc, SN 2006jc, ZTF18aakuewf
Record Number:CaltechAUTHORS:20191121-153338582
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:100003
Deposited By: Tony Diaz
Deposited On:21 Nov 2019 23:46
Last Modified:09 Mar 2020 13:18

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