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SN Refsdal: Classification as a Luminous and Blue SN 1987A-like Type II Supernova

Kelly, P. L. and Brammer, G. and Selsing, J. and Foley, R. J. and Hjorth, J. and Rodney, S. A. and Christensen, L. and Strolger, L.-G. and Filippenko, A. V. and Treu, T. and Steidel, C. C. and Strom, A. and Riess, A. G. and Zitrin, A. and Schmidt, K. B. and Bradač, M. and Jha, S. W. and Graham, M. L. and McCully, C. and Graur, O. and Weiner, B. J. and Silverman, J. M. and Taddia, F. (2016) SN Refsdal: Classification as a Luminous and Blue SN 1987A-like Type II Supernova. Astrophysical Journal, 831 (2). Art. No. 205. ISSN 0004-637X.

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We have acquired Hubble Space Telescope (HST) and Very Large Telescope near-infrared spectra and images of supernova (SN) Refsdal after its discovery as an Einstein cross in fall 2014. The HST light curve of SN Refsdal has a shape consistent with the distinctive, slowly rising light curves of SN 1987A-like SNe, and we find strong evidence for a broad Hα P-Cygni profile and Na I D absorption in the HST grism spectrum at the redshift (z = 1.49) of the spiral host galaxy. SNe IIn, largely powered by circumstellar interaction, could provide a good match to the light curve of SN Refsdal, but the spectrum of a SN IIn would not show broad and strong Hα and Na I D absorption. From the grism spectrum, we measure an Hα expansion velocity consistent with those of SN 1987A-like SNe at a similar phase. The luminosity, evolution, and Gaussian profile of the Hα emission of the WFC3 and X-shooter spectra, separated by ~2.5 months in the rest frame, provide additional evidence that supports the SN 1987A-like classification. In comparison with other examples of SN 1987A-like SNe, photometry of SN Refsdal favors bluer B − V and V − R colors and one of the largest luminosities for the assumed range of potential magnifications. The evolution of the light curve at late times will provide additional evidence about the potential existence of any substantial circumstellar material. Using MOSFIRE and X-shooter spectra, we estimate a subsolar host-galaxy metallicity (8.3 ± 0.1 dex and <8.4 dex, respectively) near the explosion site.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Kelly, P. L.0000-0003-3142-997X
Hjorth, J.0000-0002-4571-2306
Rodney, S. A.0000-0003-1947-687X
Filippenko, A. V.0000-0003-3460-0103
Treu, T.0000-0002-8460-0390
Steidel, C. C.0000-0002-4834-7260
Strom, A.0000-0001-6369-1636
Zitrin, A.0000-0002-0350-4488
Jha, S. W.0000-0001-8738-6011
Graham, M. L.0000-0002-9154-3136
McCully, C.0000-0001-5807-7893
Silverman, J. M.0000-0003-3325-3365
Taddia, F.0000-0002-2387-6801
Additional Information:© 2016 American Astronomical Society. Received 2015 December 31. Accepted 2016 August 9. Published 2016 November 9. We would like to thank Space Telescope Science Institute (STScI) director Matt Mountain for making it possible to obtain the HST WFC3 grism spectra of SN Refsdal. We express our appreciation for the efforts of HST Program Coordinator Beth Periello and Contact Scientist Norbert Pirzkal, as well as Claus Leitherer, Andrew Fox, Ken Sembach, and Miranda Link for scheduling the grism observations. Based in part on observations made with ESO telescopes at the La Silla Paranal Observatory under program ID 295.D-5014. We thank Ori Fox for helpful discussions about the Type IIn SN 2005cp, and Nathan Smith for useful comments about CSM interaction and SN 1987A-like SNe. Support for the preparation of the paper is from HST grants GO-14041 and GO-14199. The GLASS program was supported by GO-13459, and the FrontierSN photometric follow-up program has funding through GO-13386. A.Z. is supported by a Hubble Fellowship (HF2-51334.001-A) awarded by STScI, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS 5-26555. R.J.F. gratefully acknowledges support from National Science Foundation (NSF) grant AST-1518052 and the Alfred P. Sloan Foundation. Supernova research at Rutgers University (S.W.J.) is supported by NSF CAREER award AST-0847157, and NASA/Keck JPL RSA 1508337 and 1520634. C.M. is supported through NSF grant AST-1313484. The DNRF provided funding for the Dark Cosmology Centre. JMS is supported by an NSF Astronomy and Astrophysics Postdoctoral Fellowship under award AST-1302771. A.V.F.'s group at UC Berkeley has received generous financial assistance from the Christopher R. Redlich Fund, the TABASGO Foundation, Gary & Cynthia Bengier, and NSF grant AST-1211916. The work of A.V.F. was completed at the Aspen Center for Physics, which is supported by NSF grant PHY-1066293; he thanks the Center for its hospitality during the black holes workshop in 2016 June and July. This research uses services or data provided by the NOAO Science Archive. NOAO is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under a cooperative agreement with the NSF. 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. We recognize the Hawaiian community for the opportunity to conduct these observations from the summit of Mauna Kea.
Funding AgencyGrant Number
NASA Hubble FellowshipHF2-51334.001-A
NASANAS 5-26555
Alfred P. Sloan FoundationUNSPECIFIED
NASA/Keck JPL RSA1508337
NASA/Keck JPL RSA1520634
Danish National Research FoundationUNSPECIFIED
NSF Astronomy and Astrophysics FellowshipAST-1302771
Christopher R. Redlich FundUNSPECIFIED
Gary and Cynthia BengierUNSPECIFIED
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:galaxies: clusters: general; galaxies: clusters: individual (MACS J1149+2223) ; gravitational lensing: strong; supernovae: general; supernovae: individual (SN Refsdal)
Issue or Number:2
Record Number:CaltechAUTHORS:20161118-133421969
Persistent URL:
Official Citation:P. L. Kelly et al 2016 ApJ 831 205
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:72171
Deposited By: Ruth Sustaita
Deposited On:18 Nov 2016 22:25
Last Modified:22 Nov 2019 00:36

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