Exploring the spectral diversity of low-redshift Type Ia supernovae using the Palomar Transient Factory
Abstract
We present an investigation of the optical spectra of 264 low-redshift (z < 0.2) Type Ia supernovae (SNe Ia) discovered by the Palomar Transient Factory, an untargeted transient survey. We focus on velocity and pseudo-equivalent width measurements of the Si II 4130, 5972, and 6355 Å lines, as well those of the Ca IInear-infrared (NIR) triplet, up to +5 days relative to the SN B-band maximum light. We find that a high-velocity component of the Ca II NIR triplet is needed to explain the spectrum in ∼95 per cent of SNe Ia observed before −5 days, decreasing to ∼80 per cent at maximum. The average velocity of the Ca II high-velocity component is ∼8500 km s^(−1) higher than the photospheric component. We confirm previous results that SNe Ia around maximum light with a larger contribution from the high-velocity component relative to the photospheric component in their Ca II NIR feature have, on average, broader light curves and lower Ca II NIR photospheric velocities. We find that these relations are driven by both a stronger high-velocity component and a weaker contribution from the photospheric Ca II NIR component in broader light curve SNe Ia. We identify the presence of C II in very-early-time SN Ia spectra (before −10 days), finding that >40 per cent of SNe Ia observed at these phases show signs of unburnt material in their spectra, and that C II features are more likely to be found in SNe Ia having narrower light curves.
Additional Information
© 2014 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2014 August 4. Received 2014 August 1; in original form 2014 May 31. Published: 15 September 2014. KM is supported by a Marie Curie Intra-European Fellowship, within the 7th European Community Framework Programme (FP7). MS acknowledges support from the Royal Society. AGY is supported by the EU/FP7-ERC grant no [307260], the Quantum Universe I-Core program by the Israeli Committee for planning and funding, the ISF, GIF, Minerva, and ISF grants, and Kimmel and ARCHES awards. NC acknowledges support from the Lyon Institute of Origins under grant ANR-10-LABX-66. MMK acknowledges generous support from the Hubble Fellowship and Carnegie-Princeton Fellowship. JMS is supported by an NSF Astronomy and Astrophysics Postdoctoral Fellowship under award AST-1302771. AVF's supernova group at UC Berkeley has received generous financial assistance from Gary and Cynthia Bengier, the Christopher R. Redlich Fund, the Richard and Rhoda Goldman Fund, the TABASGO Foundation, and NSF grant AST-1211916. The William Herschel Telescope is operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. Based on observations (GN-2010A-Q-20, GN- 2010B-Q-13, GN-2011A-Q-16 and GS-2009B-Q-11) obtained at the Gemini Observatory, 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 National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovação (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina). Observations were 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, La Cumbres Observatory, the Lawrence Berkeley National Laboratory, the National Energy Research Scientific Computing Center, the University of Oxford, and the Weizmann Institute of Science. The authors would like to thank all the observers and data reducers of the collaboration for their hard work throughout the survey (in particular I. Arcavi, S. Ben-Ami, J. Bloom, S. B. Cenko, M. Graham, A. Horesh, E. Hsiao, I. Kleiser, S. Kulkarni, A. Miller, E. Ofek, J. Parrent, D. Perley, R. Quimby, A. Sternberg, N. Suzuki, O. Yaron, D. Xu). This publication has been made possible by the participation of more than 10 000 volunteers in the Galaxy Zoo: Supernova project (http://supernova.galaxyzoo.org/authors). The LT is operated on the island of La Palma by Liverpool John Moores University in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias with financial support from the UK Science and Technology Facilities Council. This work also makes use of observations from the LCOGT network. 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. We thank the dedicated staffs at all the observatories we used for their excellent assistance with the observations. Based on data taken at the European Organization for Astronomical Research in the Southern hemisphere, Chile, under program IDs 084.A-0149(A) and 085.A-0777(A). Observations obtained with the SuperNova Integral Field Spectrograph on the University of Hawaii 2.2-m telescope as part of the Nearby Supernova Factory II project, a scientific collaboration between the Centre de Recherche Astronomique de Lyon, Institut de Physique Nucléaire de Lyon, Laboratoire de Physique Nucléaire et des Hautes Energies, Lawrence Berkeley National Laboratory, Yale University, University of Bonn, Max Planck Institute for Astrophysics, Tsinghua Center for Astrophysics, and Centre de Physique des Particules de Marseille. This research has made use of 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 - stu1607.pdf
Submitted - 1408.1430v1.pdf
Supplemental Material - stu1607_Supplementary_Data.zip
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Additional details
- Eprint ID
- 62587
- Resolver ID
- CaltechAUTHORS:20151203-143133454
- Marie Curie Fellowship
- Royal Society
- 307260
- European Research Council (ERC)
- Israeli Committee Quantum Universe I-Core program
- Israel Science Foundation
- German-Israeli Foundation for Scientific Research and Development
- Minerva
- ANR-10-LABX-66
- Agence Nationale pour la Recherche (ANR)
- NASA Hubble Fellowship
- Carnegie-Princeton Fellowship
- AST-1302771
- NSF Astronomy and Astrophysics Fellowship
- Gary and Cynthia Bengier
- Christopher R. Redlich Fund
- Richard and Rhoda Goldman Fund
- TABASGO Foundation
- AST-1211916
- NSF
- W. M. Keck Foundation
- NASA/JPL/Caltech
- Kimmel Award
- ARCHES Award
- Created
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2015-12-03Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Palomar Transient Factory