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Constraints on Circumstellar Material around the Type Ia Supernova 2007af

Simon, Joshua D. and Gal-Yam, Avishay and Penprase, Bryan E. and Li, Weidong and Quimby, Robert M. and Silverman, Jeffrey M. and Allende Prieto, Carlos and Wheeler, J. Craig and Filippenko, Alexei V. and Martinez, Irene T. and Beeler, Daniel J. and Patat, Ferdinando (2007) Constraints on Circumstellar Material around the Type Ia Supernova 2007af. Astrophysical Journal, 671 (1). L25-L28. ISSN 0004-637X. doi:10.1086/524707.

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Patat et al. recently inferred the existence of circumstellar material around a normal Type Ia supernova (SN Ia) for the first time, finding time-variable Na I D absorption lines in the spectrum of SN 2006X. We present high-resolution spectroscopy of the bright SN Ia 2007af at three epochs and search for variability in any of the Na D absorption components. Over the time range from 4 days before to 24 days after maximum light, we find that the host-galaxy Na D lines appear to be of interstellar rather than circumstellar origin and do not vary down to the level of 18 mÅ (column density of 2 × 10^(11) cm^(-2)). We limit any circumstellar absorption lines to be weaker than ~10 mÅ (6 × 10^(10) cm^(-2)). For the case of material distributed in spherically symmetric shells of radius ~10^(16) cm surrounding the progenitor system, we place an upper limit on the shell mass of ~(3 × 10^(-8))/X M_⊙, where X is the Na ionization fraction. We also show that SN 2007af is a photometrically and spectroscopically normal SN Ia. Assuming that the variable Na D lines in SN 2006X came from circumstellar matter, we therefore conclude that either there is a preferred geometry for the detection of variable absorption components in SNe Ia, or SN 2007af and SN 2006X had different types of progenitor systems.

Item Type:Article
Related URLs:
URLURL TypeDescription DOIArticle
Gal-Yam, Avishay0000-0002-3653-5598
Quimby, Robert M.0000-0001-9171-5236
Silverman, Jeffrey M.0000-0003-3325-3365
Allende Prieto, Carlos0000-0002-0084-572X
Filippenko, Alexei V.0000-0003-3460-0103
Patat, Ferdinando0000-0002-0537-3573
Additional Information:© 2007 The American Astronomical Society. Received 2007 September 6; accepted 2007 October 18; published 2007 November 8. This publication was based in part on observations obtained with the APO 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium. The HET is named in honor of its principal benefactors, William P. Hobby and Robert E. Eberly. The authors also wish to 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.We thank the referee, Nikolai Chugai, for constructive comments. J. D. S. acknowledges the support of a Millikan Fellowship provided by Caltech. R. Q. and J. C. W. are supported in part by NSF grant AST-0707769, and C. A. P. acknowledges support from NASA under grants NAG5–13057 and NAG5–13147. A. V. F.’s group at U.C. Berkeley is supported by NSF grant AST-0607485, the Sylvia and Jim Katzman Foundation, and the TABASGO Foundation. We thank Wal Sargent and Michael Rauch profusely for the Keck spectrum, HET resident astronomer Heinz Edelmann for carrying out the HET observations, and George Becker for helpful conversations.
Funding AgencyGrant Number
Robert A. Millikan FellowshipUNSPECIFIED
Sylvia and Jim Katzman FoundationUNSPECIFIED
Subject Keywords:circumstellar matter; supernovae : general; supernovae : individual (SN 2006X, SN 2007af)
Issue or Number:1
Record Number:CaltechAUTHORS:20100113-084638727
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:17156
Deposited By: Tony Diaz
Deposited On:19 Jan 2010 20:25
Last Modified:08 Nov 2021 23:33

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