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The rising light curves of Type Ia supernovae

Firth, R. E. and Sullivan, M. and Gal-Yam, A. and Howell, D. A. and Maguire, K. and Nugent, P. and Piro, A. L. and Baltay, C. and Feindt, U. and Hadjiyksta, E. and McKinnon, R. and Ofek, E. and Rabinowitz, D. and Walker, E. S. (2015) The rising light curves of Type Ia supernovae. Monthly Notices of the Royal Astronomical Society, 446 (4). pp. 3895-3910. ISSN 0035-8711.

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We present an analysis of the early, rising light curves of 18 Type Ia supernovae (SNe Ia) discovered by the Palomar Transient Factory and the La Silla-QUEST variability survey. We fit these early data flux using a simple power law (f(t) = α × t^n) to determine the time of first light (t_0), and hence the rise time (t_(rise)) from first light to peak luminosity, and the exponent of the power-law rise (n). We find a mean uncorrected rise time of 18.98 ± 0.54 d, with individual supernova (SN) rise times ranging from 15.98 to 24.7 d. The exponent n shows significant departures from the simple ‘fireball model’ of n = 2 (or f(t) ∝ t^2) usually assumed in the literature. With a mean value of n = 2.44 ± 0.13, our data also show significant diversity from event to event. This deviation has implications for the distribution of ^(56)Ni throughout the SN ejecta, with a higher index suggesting a lesser degree of ^(56)Ni mixing. The range of n found also confirms that the ^(56)Ni distribution is not standard throughout the population of SNe Ia, in agreement with earlier work measuring such abundances through spectral modelling. We also show that the duration of the very early light curve, before the luminosity has reached half of its maximal value, does not correlate with the light-curve shape or stretch used to standardize SNe Ia in cosmological applications. This has implications for the cosmological fitting of SN Ia light curves.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper Information
Sullivan, M.0000-0001-9053-4820
Gal-Yam, A.0000-0002-3653-5598
Howell, D. A.0000-0003-4253-656X
Maguire, K.0000-0002-9770-3508
Nugent, P.0000-0002-3389-0586
Piro, A. L.0000-0001-6806-0673
Feindt, U.0000-0002-9435-2167
Ofek, E.0000-0002-6786-8774
Additional Information:© 2014 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2014 October 30. Received 2014 October 30. In original form 2014 July 7. First published online December 9, 2014. We wish to thank the Reviewer for a careful and considered reading, and thorough and helpful report. MS acknowledges support from the Royal Society and EU/FP7-ERC grant no [615929]. KM is supported by a Marie Curie Intra European Fellowship, within the 7th European Community Framework Programme (FP7). This research used resources of the National Energy Research Scientific Computing Center, which is supported by the Office of Science of the US Department of Energy under Contract no. DE-AC02-05CH11231. EO is incumbent of the Arye Dissentshik career development chair and is grateful to support by grants from the Willner Family Leadership Institute Ilan Gluzman (Secaucus NJ), Israeli Ministry of Science, Israel Science Foundation, Minerva, Weizmann-UK and the I-CORE Programme of the Planning and Budgeting Committee and The Israel Science Foundation. Observations obtained with the Samuel Oschin Telescope at the Palomar Observatory as part of the Palomar Transient Factory project, a scientific collaboration between the California Institute of Technology, Columbia University, Las Cumbres Observatory, the Lawrence Berkeley National Laboratory, the National Energy Research Scientific Computing Center, the University of Oxford, and the Weizmann Institute of Science. 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. This research was made possible through the use of the AAVSO Photometric All-Sky Survey (APASS), funded by the Robert Martin Ayers Sciences Fund.
Group:Palomar Transient Factory
Funding AgencyGrant Number
European Research Council (ERC)615929
Marie Curie FellowshipUNSPECIFIED
Department of Energy (DOE)DE-AC02-05CH11231
Willner Family Leadership Institute Ilan GluzmanUNSPECIFIED
Ministry of Science (Israel)UNSPECIFIED
Israel Science FoundationUNSPECIFIED
Planning and Budgeting Committee I-CORE ProgramUNSPECIFIED
W. M. Keck FoundationUNSPECIFIED
Robert Martin Ayers Sciences FundUNSPECIFIED
Subject Keywords:supernovae: general
Issue or Number:4
Record Number:CaltechAUTHORS:20150407-085321395
Persistent URL:
Official Citation:R. E. Firth, M. Sullivan, A. Gal-Yam, D. A. Howell, K. Maguire, P. Nugent, A. L. Piro, C. Baltay, U. Feindt, E. Hadjiyksta, R. McKinnon, E. Ofek, D. Rabinowitz, and E. S. Walker The rising light curves of Type Ia supernovae MNRAS (February 2015) Vol. 446 3895-3910 doi:10.1093/mnras/stu2314 First published online December 9, 2014
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:56414
Deposited By: Ruth Sustaita
Deposited On:07 Apr 2015 17:36
Last Modified:22 Nov 2019 03:20

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