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SN 2015U: A Rapidly Evolving and Luminous Type Ibn Supernova

Shivvers, Isaac and Zheng, WeiKang and Mauerhan, Jon and Kleiser, Io K. W. and Van Dyk, Schuyler D. and Silverman, Jeffrey M. and Graham, Melissa L. and Kelly, Patrick L. and Filippenko, Alexei V. and Kumar, Sahana (2016) SN 2015U: A Rapidly Evolving and Luminous Type Ibn Supernova. Monthly Notices of the Royal Astronomical Society, 461 (3). pp. 3057-3074. ISSN 0035-8711.

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Supernova (SN) 2015U (also known as PSN J07285387+3349106) was discovered in NGC 2388 on 2015 Feb. 11. A rapidly evolving and luminous event, it showed effectively hydrogen-free spectra dominated by relatively narrow helium P-Cygni spectral features and it was classified as an SN Ibn. In this paper, we present photometric, spectroscopic, and spectropolarimetric observations of SN 2015U, including a Keck/DEIMOS spectrum (resolution ≈5000) which fully resolves the optical emission and absorption features. We find that SN 2015U is best understood via models of shock breakout from extended and dense circumstellar material (CSM), likely created by a history of mass-loss from the progenitor with an extreme outburst within ∼1–2 yr of core collapse (but we do not detect any outburst in our archival imaging of NGC 2388). We argue that the high luminosity of SN 2015U was powered not through ^(56)Ni decay but via the deposition of kinetic energy into the ejecta/CSM shock interface. Though our analysis is hampered by strong host-galaxy dust obscuration (which likely exhibits multiple components), our data set makes SN 2015U one of the best-studied Type Ibn SNe and provides a bridge of understanding to other rapidly fading transients, both luminous and relatively faint.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Shivvers, Isaac0000-0003-3373-8047
Zheng, WeiKang0000-0002-2636-6508
Van Dyk, Schuyler D.0000-0001-9038-9950
Silverman, Jeffrey M.0000-0003-3325-3365
Graham, Melissa L.0000-0002-9154-3136
Kelly, Patrick L.0000-0003-3142-997X
Filippenko, Alexei V.0000-0003-3460-0103
Additional Information:© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2016 June 22. Received 2016 June 20. In original form 2016 March 4. First published online June 26, 2016. The authors thank M. Drout, R. Foley, P. Nugent, D. Kasen, E. Quataert, D. Poznanski, and O. Fox for useful comments and discussions. We are grateful to our referee, A. Pastorello, for comments that have greatly improved this effort. We thank the HST, Keck Observatory, and Lick Observatory staffs for their expert assistance with the observations. We also acknowledge the following Nickel 1 m observers and KAIT checkers for their valuable assistance with this work: A. Bigley, C. Gould, G. Halevi, K. Hayakawa, A. Hughes, H.J. Kim, M. Kim, P. Lu, K. Pina, T. Ross, S. Stegman, and H. Yuk. AVF's SN research group at U. C. Berkeley is supported by NSF grant AST-1211916, the TABASGO Foundation, Gary and Cynthia Bengier, and the Christopher R. Redlich Fund. Additional assistance is provided by NASA/HST grants AR-14295 and GO-14149 from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. JMS is supported by an NSF Astronomy and Astrophysics Postdoctoral Fellowship under award AST-1302771. 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. KAIT and its ongoing operation were supported by donations from Sun Microsystems, Inc., the Hewlett-Packard Company, AutoScope Corporation, Lick Observatory, the NSF, the University of California, the Sylvia and Jim Katzman Foundation, and the TABASGO Foundation. Research at Lick Observatory is partially supported by a very generous gift from Google, as well as by contributions from numerous individuals including Eliza Brown and Hal Candee, Kathy Burck and Gilbert Montoya, David and Linda Cornfield, William and Phyllis Draper, Luke Ellis and Laura Sawczuk, Alan and Gladys Hoefer, DuBose and Nancy Montgomery, Jeanne and Sanford Robertson, Stanley and Miriam Schiffman, Thomas and Alison Schneider, the Hugh Stuart Center Charitable Trust, Mary-Lou Smulders and Nicholas Hodson, Clark and Sharon Winslow, Weldon and Ruth Wood, and many others. This research was based in part on data taken with the NASA/ESA HST, and obtained from the Hubble Legacy Archive, which is a collaboration between the Space Telescope Science Institute (STScI/NASA), the Space Telescope European Coordinating Facility (ST-ECF/ESA), and the Canadian Astronomy Data Centre (CADC/NRC/CSA). We also made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Gary and Cynthia BengierUNSPECIFIED
Christopher R. Redlich FundUNSPECIFIED
W. M. Keck FoundationUNSPECIFIED
Sun Microsystems, Inc.UNSPECIFIED
Hewlett-Packard CompanyUNSPECIFIED
AutoScope CorporationUNSPECIFIED
Lick ObservatoryUNSPECIFIED
University of CaliforniaUNSPECIFIED
Sylvia and Jim Katzman FoundationUNSPECIFIED
Subject Keywords: stars: mass-loss supernovae: individual: SN 2015U
Issue or Number:3
Record Number:CaltechAUTHORS:20161017-075754262
Persistent URL:
Official Citation:Isaac Shivvers, WeiKang Zheng, Jon Mauerhan, Io K. W. Kleiser, Schuyler D. Van Dyk, Jeffrey M. Silverman, Melissa L. Graham, Patrick L. Kelly, Alexei V. Filippenko, and Sahana Kumar SN 2015U: a rapidly evolving and luminous Type Ibn supernova MNRAS (September 21, 2016) Vol. 461 3057-3074 doi:10.1093/mnras/stw1528 first published online June 26, 2016
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:71135
Deposited By: Ruth Sustaita
Deposited On:17 Oct 2016 17:15
Last Modified:22 Nov 2019 05:56

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