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Published September 11, 2014 | Supplemental Material + Published
Journal Article Open

Multi-epoch high-spectral-resolution observations of neutral sodium in 14 Type Ia supernovae


One of the main questions concerning Type Ia supernovae is the nature of the binary companion of the exploding white dwarf. A major discriminant between different suggested models is the presence and physical properties of circumstellar material at the time of explosion. If present, this material will be ionized by the ultraviolet radiation of the explosion and later recombine. This ionization–recombination should manifest itself as time-variable absorption features that can be detected via multi-epoch high-spectral-resolution observations. Previous studies have shown that the strongest effect is seen in the neutral sodium D lines. We report on observations of neutral sodium absorption features observed in multi-epoch high-resolution spectra of 14 Type Ia supernova events. This is the first multi-epoch high-resolution study to include multiple SNe. No variability in line strength that can be associated with circumstellar material is detected in the events presented in this paper. If we include previously published events, we find that ∼18 per cent of the events in the extended sample exhibit time-variable sodium features associated with circumstellar material. We explore the implication of this study on our understanding of the progenitor systems of Type Ia supernovae via the current Type Ia supernova multi-epoch high-spectral-resolution sample.

Additional Information

© 2014 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2014 June 17. Received 2014 June 16; in original form 2013 November 14. We thank the anonymous referee for his comments that help us improve our paper. AS is supported by a Minerva Fellowship. The research of AG is supported by the EU/FP7 via an ERC grant no. 307260, the Minerva ARCHES prize and the Kimmel award. The authors would like to acknowledge the generosity of the late Wallace L. W. Sargent in providing data. The authors would also like to acknowledge the help of D. J. Osip and J. F. Steiner in obtaining the data. Partially based on observations made with ESO Telescopes at the La Silla Paranal Observatory, Chile, under programme ID 289.D-5023, 290.D-5010, 290.D-5023, 091.D-0780. This paper includes data gathered with the 6.5 metre Magellan Telescopes located at Las Campanas Observatory, Chile. 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. 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. Partially based on observations made with ESO Telescopes at the La Silla Paranal Observatory, Chile, under programme. ID 289.D-5023, 290.D-5010, 290.D-5023, 091.D-0780.

Attached Files

Published - MNRAS-2014-Sternberg-1849-60.pdf

Supplemental Material - 1311.3645v1.pdf


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August 22, 2023
October 17, 2023