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Flash Spectroscopy: Emission Lines from the Ionized Circumstellar Material around <10-Day-Old Type II Supernovae

Khazov, D. and Kulkarni, S. R. and Kasliwal, M. M. and Cao, Y. and Perley, D. and Laher, R. R. and Surace, J. (2016) Flash Spectroscopy: Emission Lines from the Ionized Circumstellar Material around <10-Day-Old Type II Supernovae. Astrophysical Journal, 818 (1). Art. No. 3. ISSN 0004-637X. doi:10.3847/0004-637X/818/1/3.

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Supernovae (SNe) embedded in dense circumstellar material (CSM) may show prominent emission lines in their early-time spectra (≤10 days after the explosion), owing to recombination of the CSM ionized by the shock-breakout flash. From such spectra ("flash spectroscopy"), we can measure various physical properties of the CSM, as well as the mass-loss rate of the progenitor during the year prior to its explosion. Searching through the Palomar Transient Factory (PTF and iPTF) SN spectroscopy databases from 2009 through 2014, we found 12 SNe II showing flash-ionized (FI) signatures in their first spectra. All are younger than 10 days. These events constitute 14% of all 84 SNe in our sample having a spectrum within 10 days from explosion, and 18% of SNe II observed at ages <5 days, thereby setting lower limits on the fraction of FI events. We classified as "blue/featureless" (BF) those events having a first spectrum that is similar to that of a blackbody, without any emission or absorption signatures. It is possible that some BF events had FI signatures at an earlier phase than observed, or that they lack dense CSM around the progenitor. Within 2 days after explosion, 8 out of 11 SNe in our sample are either BF events or show FI signatures. Interestingly, we found that 19 out of 21 SNe brighter than an absolute magnitude M_R = −18.2 belong to the FI or BF groups, and that all FI events peaked above M_R = −17.6 mag, significantly brighter than average SNe II.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Kulkarni, S. R.0000-0001-5390-8563
Kasliwal, M. M.0000-0002-5619-4938
Cao, Y.0000-0002-8036-8491
Perley, D.0000-0001-8472-1996
Laher, R. R.0000-0003-2451-5482
Surace, J.0000-0001-7291-0087
Additional Information:© 2016 The American Astronomical Society. Received 2015 June 23; accepted 2015 November 30; published 2016 February 2. We would like to acknowledge A. Miller, D. Poznanski, J. Bloom, K. Clubb, D. Murray, S. Tang, S. Geier, V. Van Eylen, and J. Parrent for help with the observations. We are grateful to the staffs at the various observatories and telescopes with which we collected data (Lick, Palomar, Keck, Gemini, NOT, Apache Point, Kitt Peak, HET) for their excellent assistance. An anonymous referee careful read our manuscript and provided valuable comments. A.G.-Y. is supported by the EU/FP7 via ERC grant no. 307260, the Quantum universe I-Core program by the Israeli Committee for planning and budgeting, and the ISF, Minerva and ISF grants, WIS-UK "making connections," and the Kimmel and ARCHES awards. J.M.S. is supported by a National Science Foundation (NSF) Astronomy and Astrophysics Postdoctoral Fellowship under award AST-1302771. A.V.F.'s research was made possible by NSF grant AST-1211916, the TABASGO Foundation, and the Christopher R. Redlich Fund. M.S. acknowledges support from the Royal Society and EU/FP7-ERC grant No. [615929]. LANL participation in iPTF is supported by the US Department of Energy as part of the Laboratory Directed Research and Development program. A portion of this work was carried out at the Jet Propulsion Laboratory under a Research and Technology Development Grant, under contract with the National Aeronautics and Space Administration. US Government Support Acknowledged. Research at Lick Observatory is partially supported by a generous gift from Google. 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. Based in part on observations obtained at the Gemini Observatory under program GN-2010B-Q-13, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the NSF (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciencia, Tecnologia e Inovacao (Brazil), and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).
Group:Palomar Transient Factory, Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
European Research Council (ERC)307260
Israeli Committee Quantum Universe I-Core programUNSPECIFIED
Israeli Committee for Planning and BudgetingUNSPECIFIED
Israeli Science FoundationUNSPECIFIED
Christopher R. Redlich FundUNSPECIFIED
European Research Council (ERC)615929
Department of Energy (DOE)UNSPECIFIED
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:supernovae: general
Issue or Number:1
Record Number:CaltechAUTHORS:20160126-070703893
Persistent URL:
Official Citation:D. Khazov et al 2016 ApJ 818 3
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:63956
Deposited By: Ruth Sustaita
Deposited On:26 Jan 2016 18:42
Last Modified:10 Nov 2021 23:23

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