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Asphericity, Interaction, and Dust in the Type II-P/II-L Supernova 2013EJ in Messier 74

Mauerhan, Jon C. and Van Dyk, Schuyler D. and Johansson, Joel and Hu, Maokai and Fox, Ori D. and Wang, Lifan and Graham, Melissa L. and Filippenko, Alexei V. and Shivvers, Isaac (2017) Asphericity, Interaction, and Dust in the Type II-P/II-L Supernova 2013EJ in Messier 74. Astrophysical Journal, 834 (2). Art. No. 118. ISSN 0004-637X. doi:10.3847/1538-4357/834/2/118.

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SN 2013ej is a well-studied core-collapse supernova (SN) that stemmed from a directly identified red supergiant (RSG) progenitor in galaxy M74. The source exhibits signs of substantial geometric asphericity, X-rays from persistent interaction with circumstellar material (CSM), thermal emission from warm dust, and a light curve that appears intermediate between supernovae of Types II-P and II-L. The proximity of this source motivates a close inspection of these physical characteristics and their potential interconnection. We present multiepoch spectropolarimetry of SN 2013ej during the first 107 days and deep optical spectroscopy and ultraviolet through infrared photometry past ~800 days. SN 2013ej exhibits the strongest and most persistent continuum and line polarization ever observed for a SN of its class during the recombination phase. Modeling indicates that the data are consistent with an oblate ellipsoidal photosphere, viewed nearly edge-on and probably augmented by optical scattering from circumstellar dust. We suggest that interaction with an equatorial distribution of CSM, perhaps the result of binary evolution, is responsible for generating the photospheric asphericity. Relatedly, our late-time optical imaging and spectroscopy show that asymmetric CSM interaction is ongoing, and the morphology of broad Hα emission from shock-excited ejecta provides additional evidence that the geometry of the interaction region is ellipsoidal. Alternatively, a prolate ellipsoidal geometry from an intrinsically bipolar explosion is also a plausible interpretation of the data but would probably require a ballistic jet of radioactive material capable of penetrating the hydrogen envelope early in the recombination phase. Finally, our latest space-based optical imaging confirms that the late interaction-powered light curve dropped below the stellar progenitor level, confirming the RSG star's association with the explosion.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Van Dyk, Schuyler D.0000-0001-9038-9950
Fox, Ori D.0000-0003-2238-1572
Graham, Melissa L.0000-0002-9154-3136
Filippenko, Alexei V.0000-0003-3460-0103
Shivvers, Isaac0000-0003-3373-8047
Additional Information:© 2017 The American Astronomical Society. Received 2016 September 23; revised 2016 October 27; accepted 2016 November 22; published 2017 January 9. J.C.M. would like to thank Nathan Smith for informative scientific discussion and commentary on this manuscript. Support for HST programs GO-14116 and GO-14668 was provided by NASA through grants from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. We are grateful to the staffs at the Lick and Keck Observatories for their excellent assistance. This work is based in part on observations from the Low-resolution Imaging Spectrometer at the Keck I telescope. The W. M. Keck Observatory is operated as a scientific partnership among Caltech, the University of California, and NASA; it was made possible by the generous financial support of the W. M. Keck Foundation. We extend special thanks to those of Hawaiian ancestry on whose sacred mountain we are privileged to be guests. A.V.F.'s group at U.C. Berkeley is supported by National Science Foundation grant AST-1211916, Gary and Cynthia Bengier, the Richard and Rhoda Goldman Fund, the Christopher R. Redlich Fund, and the TABASGO Foundation. Research at the Lick Observatory is partially supported by a generous gift from Google. This work is based in part on observations and in part on archival data obtained with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory (JPL), Caltech, under a contract with NASA; support was provided by NASA through an award issued by JPL/Caltech.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
W. M. Keck FoundationUNSPECIFIED
Gary and Cynthia BengierUNSPECIFIED
Richard and Rhoda Goldman FundUNSPECIFIED
Christopher R. Redlich FundUNSPECIFIED
Subject Keywords:galaxies: individual (NGC 628) – supernovae: general – supernovae: individual (SN 2013ej)
Issue or Number:2
Record Number:CaltechAUTHORS:20170109-134018634
Persistent URL:
Official Citation:Jon C. Mauerhan et al 2017 ApJ 834 118
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:73340
Deposited By: Tony Diaz
Deposited On:09 Jan 2017 21:48
Last Modified:11 Nov 2021 05:15

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