The Absolute Magnitudes of 1991T-like Supernovae
- Creators
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Phillips, M. M.
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Ashall, C.
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Burns, Christopher R.
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Contreras, Carlos
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Galbany, L.
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Hoeflich, P.
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Hsiao, E. Y.
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Morrell, Nidia
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Nugent, Peter
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Uddin, Syed A.
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Baron, E.
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Freedman, Wendy L.
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Harris, Chelsea E.
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Krisciunas, Kevin
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Kumar, S.
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Lu, J.
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Persson, S. E.
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Piro, Anthony L.
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Polin, Abigail
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Shahbandeh, M.
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Stritzinger, Maximilian
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Suntzeff, Nicholas B.
Abstract
1991T-like supernovae are the luminous, slow-declining extreme of the Branch shallow-silicon (SS) subclass of Type Ia supernovae. They are distinguished by extremely weak Ca ii H & K and Si ii λ6355 and strong Fe iii absorption features in their optical spectra at pre-maximum phases, and have long been suspected to be over-luminous compared to normal Type Ia supernovae. In this paper, the pseudo-equivalent width of the Si ii λ6355 absorption obtained at light curve phases from ≤ +10 days is combined with the morphology of the i-band light curve to identify a sample of 1991T-like supernovae in the Carnegie Supernova Project II. Hubble diagram residuals show that, at optical as well as near-infrared wavelengths, these events are over-luminous by ∼0.1–0.5 mag with respect to the less extreme Branch SS (1999aa-like) and Branch core-normal supernovae with similar B-band light-curve decline rates.
Additional Information
The work of the CSP-II has been generously supported by the National Science Foundation under grants 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. M.S. acknowledges funding by a research grant (13261) from VILLUM FONDEN. E.B. is supported in part by NASA grant 80NSSC20K0538. L.G. acknowledges financial support from the Spanish Ministerio de Ciencia e Innovación (MCIN), the Agencia Estatal de Investigación (AEI) 10.13039/501100011033, and the European Social Fund (ESF) "Investing in your future" under the 2019 Ramón y Cajal program RYC2019-027683-I and the PID2020-115253GA-I00 HOSTFLOWS project, from Centro Superior de Investigaciones Científicas (CSIC) under the PIE project 20215AT016, and the program Unidad de Excelencia María de Maeztu CEX2020-001058-M. We gratefully acknowledge the use of WISeREP—https://wiserep.weizmann.ac.il. M.M.P. thanks Richard Scalzo for interesting discussions of extreme SNe Ia. This research has made use of the NASA/IPAC Extragalactic Database (NED), which is funded by the National Aeronautics and Space Administration and operated by the California Institute of Technology. Finally, we thank the referee for suggestions on improving the text and figures.Additional details
- Eprint ID
- 117556
- Resolver ID
- CaltechAUTHORS:20221024-125854800.26
- AST-1613426
- NSF
- AST-1613455
- NSF
- AST-1613472
- NSF
- Danish Agency for Science and Technology and Innovation
- Villum Foundation
- 80NSSC20K0538
- NASA
- 20215AT016
- Ministerio de Ciencia e Innovación (MCIN)
- PID2020-115253GA-I00
- Agencia Estatal de Investigación (AEI)
- European Social Fund
- RYC2019-027683-I
- Ramón y Cajal Programme
- CEX2020-001058-M
- Unidad de Excelencia María de Maeztu
- NASA/JPL/Caltech
- Created
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2022-11-02Created from EPrint's datestamp field
- Updated
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2022-11-02Created from EPrint's last_modified field
- Caltech groups
- TAPIR, Walter Burke Institute for Theoretical Physics