Nebular spectroscopy of the nearby Type IIb supernova 2011dh
Abstract
We present nebular spectra of the nearby Type IIb supernova (SN) 2011dh taken between 201 and 678 d after core collapse. At these late times, SN 2011dh exhibits strong emission lines including a broad and persistent Hα feature. New models of the nebular spectra confirm that the progenitor of SN 2011dh was a low-mass giant (M ≈ 13–15 M_⊙) that ejected ∼ 0.07 M_⊙ of ^(56)Ni and ∼ 0.27 M_⊙ of oxygen at the time of explosion, consistent with the recent disappearance of a candidate yellow supergiant progenitor. We show that light from the SN location is dominated by the fading SN at very late times (∼2 yr) and not, for example, by a binary companion or a background source. We present evidence for interaction between the expanding SN blast wave and a circumstellar medium at late times and show that the SN is likely powered by positron deposition ≳1 yr after explosion. We also examine the geometry of the ejecta and show that the nebular line profiles of SN 2011dh indicate a roughly spherical explosion with aspherical components or clumps.
Additional Information
© 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2013 September 26. Received 2013 September 25; in original form 2013 July 3. First published online: October 23, 2013. Sincere thanks to all of the supernova experts who contributed through discussions, including (but not limited to) Brad Tucker, WeiKang Zheng, Ori Fox, Patrick Kelly and J. Craig Wheeler (whose keen eye identified a significant typo in the manuscript). We thank the referee for suggestions that helped to improve this paper. 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 the National Aeronautics and Space Administration (NASA); the observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community; we are most fortunate to have the opportunity to conduct observations from this mountain. This material is partially based upon work supported by a National Science Foundation (NSF) Graduate Research Fellowship to JB under grant no. DGE 1106400. JMS is supported by an NSF Astronomy and Astrophysics Postdoctoral Fellowship under award AST-1302771. AVF and his SN group at UC Berkeley acknowledge generous support from Gary and Cynthia Bengier, the Richard and Rhoda Goldman Fund, the Christopher R. Redlich Fund, the TABASGO Foundation and NSF grant AST-1211916. This research has made use of NASA's Astrophysics Data System Bibliographic Services, as well as the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA.Attached Files
Published - MNRAS-2013-Shivvers-3614-25.pdf
Submitted - 1307.2246v3.pdf
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Additional details
- Eprint ID
- 43338
- Resolver ID
- CaltechAUTHORS:20140113-101301085
- DGE-1106400
- NSF Graduate Research Fellowship
- AST-1302771
- NSF Astronomy and Astrophysics Fellowship
- Gary and Cynthia Bengier
- Richard and Rhoda Goldman Fund
- Christopher R. Redlich Fund
- TABASGO Foundation
- AST-1211916
- NSF
- Created
-
2014-01-14Created from EPrint's datestamp field
- Updated
-
2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)