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The Absolute Magnitudes of 1991T-like Supernovae

Phillips, M. M. and Ashall, C. and Burns, Christopher R. and Contreras, Carlos and Galbany, L. and Hoeflich, P. and Hsiao, E. Y. and Morrell, Nidia and Nugent, Peter and Uddin, Syed A. and Baron, E. and Freedman, Wendy L. and Harris, Chelsea E. and Krisciunas, Kevin and Kumar, S. and Lu, J. and Persson, S. E. and Piro, Anthony L. and Polin, Abigail and Shahbandeh, M. and Stritzinger, Maximilian and Suntzeff, Nicholas B. (2022) The Absolute Magnitudes of 1991T-like Supernovae. Astrophysical Journal, 938 (1). p. 47. ISSN 0004-637X. doi:10.3847/1538-4357/ac9305.

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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.

Item Type:Article
Related URLs:
URLURL TypeDescription
Phillips, M. M.0000-0003-2734-0796
Ashall, C.0000-0002-5221-7557
Burns, Christopher R.0000-0003-4625-6629
Contreras, Carlos0000-0001-6293-9062
Galbany, L.0000-0002-1296-6887
Hoeflich, P.0000-0002-4338-6586
Hsiao, E. Y.0000-0003-1039-2928
Morrell, Nidia0000-0003-2535-3091
Nugent, Peter0000-0002-3389-0586
Uddin, Syed A.0000-0002-9413-4186
Baron, E.0000-0001-5393-1608
Freedman, Wendy L.0000-0003-3431-9135
Harris, Chelsea E.0000-0002-1751-7474
Krisciunas, Kevin0000-0002-6650-694X
Kumar, S.0000-0001-8367-7591
Lu, J.0000-0002-3900-1452
Persson, S. E.0000-0003-0554-7083
Piro, Anthony L.0000-0001-6806-0673
Polin, Abigail0000-0002-1633-6495
Shahbandeh, M.0000-0002-9301-5302
Stritzinger, Maximilian0000-0002-5571-1833
Suntzeff, Nicholas B.0000-0002-8102-181X
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— 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.
Group:TAPIR, Walter Burke Institute for Theoretical Physics
Funding AgencyGrant Number
Danish Agency for Science and Technology and InnovationUNSPECIFIED
Villum FoundationUNSPECIFIED
Ministerio de Ciencia e Innovación (MCIN)20215AT016
Agencia Estatal de Investigación (AEI)PID2020-115253GA-I00
European Social FundUNSPECIFIED
Ramón y Cajal ProgrammeRYC2019-027683-I
Unidad de Excelencia María de MaeztuCEX2020-001058-M
Issue or Number:1
Record Number:CaltechAUTHORS:20221024-125854800.26
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:117556
Deposited By: Research Services Depository
Deposited On:02 Nov 2022 00:03
Last Modified:02 Nov 2022 00:03

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