Carnegie Supernova Project-II: Near-infrared Spectroscopic Diversity of Type II Supernovae
Creators
- Davis, S.1
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Hsiao, E. Y.1
- Ashall, C.1
- Hoeflich, P.1
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Phillips, M. M.2, 1
- Marion, G. H.3
- Kirshner, R. P.4, 5
- Morrell, N.2
- Sand, D. J.6
- Burns, C.7
- Contreras, C.2
- Stritzinger, M.8
- Anderson, J. P.9
- Baron, E.8, 10, 11
- Diamond, T.12
- Gutierrez, C. P.13
- Hamuy, M.14
- Holmbo, S.8
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Kasliwal, M. M.15
- Krisciunas, K.16
- Kumar, S.1
- Lu, J.1
- Pessi, P. J.17
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Piro, A. L.7
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Prieto, J. L.18
- Shahbandeh, M.1
- Suntzeff, N. B.16
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1.
Florida State University
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2.
Las Campanas Observatory
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3.
The University of Texas at Austin
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4.
Gordon and Betty Moore Foundation
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5.
Harvard-Smithsonian Center for Astrophysics
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6.
University of Arizona
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7.
Carnegie Observatories
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8.
Aarhus University
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9.
European Southern Observatory
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10.
University of Oklahoma
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11.
Universität Hamburg
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12.
Goddard Space Flight Center
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13.
University of Southampton
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14.
University of Chile
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15.
California Institute of Technology
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16.
Texas A&M University
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17.
National University of La Plata
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18.
Diego Portales University
Abstract
We present 81 near-infrared (NIR) spectra of 30 Type II supernovae (SNe II) from the Carnegie Supernova Project-II (CSP-II), the largest such data set published to date. We identify a number of NIR features and characterize their evolution over time. The NIR spectroscopic properties of SNe II fall into two distinct groups. This classification is first based on the strength of the He i λ1.083 μm absorption during the plateau phase; SNe II are either significantly above (spectroscopically strong) or below 50 Å (spectroscopically weak) in pseudo equivalent width. However, between the two groups other properties, such as the timing of CO formation and the presence of Sr ii, are also observed. Most surprisingly, the distinct weak and strong NIR spectroscopic classes correspond to SNe II with slow and fast declining light curves, respectively. These two photometric groups match the modern nomenclature of SNe IIP, which show a long duration plateau, and IIL, which have a linear declining light curve. Including NIR spectra previously published, 18 out of 19 SNe II follow this slow declining-spectroscopically weak and fast declining-spectroscopically strong correspondence. This is in apparent contradiction to the recent findings in the optical that slow and fast decliners show a continuous distribution of properties. The weak SNe II show a high-velocity component of helium that may be caused by a thermal excitation from a reverse shock created by the outer ejecta interacting with the red supergiant wind, but the origin of the observed dichotomy is not understood. Further studies are crucial in determining whether the apparent differences in the NIR are due to distinct physical processes or a gap in the current data set.
Additional Information
© 2019 The American Astronomical Society. Received 2019 July 25; revised 2019 October 4; accepted 2019 October 7; published 2019 December 4. The authors would like to thank the anonymous referee for their comments. The work of the CSP-II has been generously supported by the National Science Foundation (NSF) under grants AST-1008343, AST-1613426, AST-1613455, and AST-1613472. The CSP-II was also supported in part by the Danish Agency for Science and Technology and Innovation through a Sapere Aude Level 2 grant. We would like to thank Michael Cushing for his work on Spextool in processing low-resolution data. P.H. acknowledges support by the NSF grant 1715133. Research by D.J.S. is supported by NSF grants AST-1821987, AST-1821967, AST-1813708, and AST-1813466. CPG acknowledges support from EU/FP7-ERC grant no. [615929]. Support for J.L.P. is provided in part by FONDECYT through the grant 1191038 and by the Ministry of Economy, Development, and Tourism's Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics, MAS. Software: firehose (Simcoe et al. 2013), xtellcor (Vacca et al. 2003), Spextool (Cushing et al. 2004), SNID (Blondin & Tonry 2007).Attached Files
Published - Davis_2019_ApJ_887_4.pdf
Submitted - 1910.03410.pdf
Files
1910.03410.pdf
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Additional details
Identifiers
- Eprint ID
- 99987
- Resolver ID
- CaltechAUTHORS:20191121-111931871
Related works
- Describes
- https://arxiv.org/abs/1910.03410 (URL)
Funding
- NSF
- AST-1008343
- NSF
- AST-1613426
- NSF
- AST-1613455
- NSF
- AST-1613472
- Danish Agency for Science and Technology and Innovation
- NSF
- AST-1715133
- NSF
- AST-1821987
- NSF
- AST-1821967
- NSF
- AST-1813708
- NSF
- AST-1813466
- European Research Council (ERC)
- 615929
- Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)
- 1191038
- Iniciativa Científica Milenio del Ministerio de Economía, Fomento y Turismo
- IC120009
Dates
- Created
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2019-11-21Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field