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On the nature of Type IIn/Ia-CSM supernovae: optical and near-infrared spectra of SN 2012ca and SN 2013dn

Fox, Ori D. and Silverman, Jeffrey M. and Filippenko, Alexei V. and Mauerhan, Jon and Becker, Juliette C. and Borish, H. Jacob and Cenko, S. Bradley and Clubb, Kelsey I. and Graham, Melissa and Hsiao, Eric and Kelly, Patrick L. and Lee, William H. and Marion, G. H. and Milisavljevic, Dan and Parrent, Jerod and Shivvers, Isaac and Skrutskie, Michael and Smith, Nathan and Wilson, John and Zheng, WeiKang (2015) On the nature of Type IIn/Ia-CSM supernovae: optical and near-infrared spectra of SN 2012ca and SN 2013dn. Monthly Notices of the Royal Astronomical Society, 447 (1). pp. 772-785. ISSN 0035-8711.

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A growing subset of Type Ia supernovae (SNe Ia) show evidence for unexpected interaction with a dense circumstellar medium (SNe Ia-CSM). The precise nature of the progenitor, however, remains debated owing to spectral ambiguities arising from a strong contribution from the CSM interaction. Late-time spectra offer potential insight if the post-shock cold, dense shell becomes sufficiently thin and/or the ejecta begin to cross the reverse shock. To date, few high-quality spectra of this kind exist. Here we report on the late-time optical and infrared spectra of the SNe Ia-CSM 2012ca and 2013dn. These SNe Ia-CSM spectra exhibit low [Fe III]/[Fe II] ratios and strong [Ca II] at late epochs. Such characteristics are reminiscent of the super-Chandrasekhar-mass (SC) candidate SN 2009dc, for which these features suggested a low-ionisation state due to high densities, although the broad Fe features admittedly show similarities to the blue “quasi-continuum” observed in some core-collapse SNe Ibn and IIn. Neither SN 2012ca nor any of the other SNe Ia-CSM show evidence for broad oxygen, carbon, or magnesium in their spectra. Similar to the interacting Type IIn SN 2005ip, a number of high-ionisation lines are identified in SN 2012ca, including [S III], [Ar III], [Ar X], [Fe VIII], [Fe X], and possibly [Fe XI]. The total bolometric energy output does not exceed 10^(51) erg, but does require a large kinetic-to-radiative conversion efficiency. All of these observations taken together suggest that SNe Ia-CSM are more consistent with a thermonuclear explosion than a core-collapse event, although detailed radiative transfer models are certainly necessary to confirm these results.

Item Type:Article
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URLURL TypeDescription DOIArticle Paper
Fox, Ori D.0000-0003-2238-1572
Silverman, Jeffrey M.0000-0003-3325-3365
Filippenko, Alexei V.0000-0003-3460-0103
Becker, Juliette C.0000-0002-7733-4522
Cenko, S. Bradley0000-0003-1673-970X
Graham, Melissa0000-0002-9154-3136
Kelly, Patrick L.0000-0003-3142-997X
Milisavljevic, Dan0000-0002-0763-3885
Shivvers, Isaac0000-0003-3373-8047
Zheng, WeiKang0000-0002-2636-6508
Alternate Title:On the Nature of Type Ia-CSM Supernovae: Optical and Near-Infrared Spectra of SN 2012ca and SN 2013dn
Additional Information:© 2014 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2014 November 17. Received 2014 November 13; in original form 2014 August 20. First published online December 19, 2014. We thank the referee, Stefano Benetti, for useful comments that strengthened this paper. Insightful discussions were shared with many at the Aspen Center for Physics, including Ryan Foley, Ryan Chornock, and Craig Wheeler. This work was supported in part by NSF Grant No. PHYS-1066293 and the hospitality of the Aspen Center for Physics. 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 are grateful to the staffs of the Lick and Keck Observatory for their assistance with the observations, and thank the RATIR instrument team and the staff of the Observatorio Astronomíco Nacional on Sierra San Pedro Mártir. RATIR is a collaboration between the University of California, the Universidad Nacional Autonomá de México, NASA Goddard Space Flight Center, and Arizona State University, benefiting from the loan of an H2RG detector from Teledyne Scientific and Imaging. RATIR, the automation of the Harold L. Johnson Telescope of the Observatorio Astronomíco Nacional on Sierra, San Pedro, Mártir, and the operation of both is funded by the partner institutions and through NASA grants NNX09AH71G, NNX09AT02G, NNX10AI27G, and NNX12AE66G, CONACyT grant INFR-2009-01-122785, UNAM PAPIIT grant IN113810, and a UC MEXUS-CONACyT grant. JMS is supported by an NSF Astronomy and Astrophysics Postdoctoral Fellowship under award AST-1302771. AVF’s supernova group at UC Berkeley received support through NSF grant AST-1211916, the TABASGO Foundation, Gary and Cynthia Bengier, the Richard and Rhoda Goldman Fund, and the Christopher R. Redlich Fund.
Funding AgencyGrant Number
W. M. Keck FoundationUNSPECIFIED
Consejo Nacional de Ciencia y Tecnología (CONACYT)INFR-2009-01-122785
Gary and Cynthia BengierUNSPECIFIED
Richard and Rhoda Goldman FundUNSPECIFIED
Christopher R. Redlich FundUNSPECIFIED
Subject Keywords:circumstellar matter; supernovae: general; supernovae: individual: SN2005ip; supernovae: individual: SN 2009dc; supernovae: individual: SN 2012ca; supernovae: individual: SN 2013dn
Issue or Number:1
Record Number:CaltechAUTHORS:20141218-075518482
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Official Citation:Ori D. Fox, Jeffrey M. Silverman, Alexei V. Filippenko, Jon Mauerhan, Juliette Becker, H. Jacob Borish, S. Bradley Cenko, Kelsey I. Clubb, Melissa Graham, Eric Hsiao, Patrick L. Kelly, William H. Lee, G. H. Marion, Dan Milisavljevic, Jerod Parrent, Isaac Shivvers, Michael Skrutskie, Nathan Smith, John Wilson, and Weikang Zheng On the nature of Type IIn/Ia–CSM supernovae: optical and near-infrared spectra of SN 2012ca and SN 2013dn MNRAS (February 11, 2015) Vol. 447 772-785 doi:10.1093/mnras/stu2435 First published online December 19, 2014
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:52998
Deposited By: Ruth Sustaita
Deposited On:18 Dec 2014 16:50
Last Modified:22 Nov 2019 05:59

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