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Title: The Absolute Magnitudes of 1991T-like Supernovae *
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 CaiiH & K and Siiiλ6355 and strong Feiiiabsorption 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 Siiiλ6355 absorption obtained at light curve phases from ≤ +10 days is combined with the morphology of thei-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 similarB-band light-curve decline rates.

 
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NSF-PAR ID:
10373543
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more » ; ; « less
Publisher / Repository:
DOI PREFIX: 10.3847
Date Published:
Journal Name:
The Astrophysical Journal
Volume:
938
Issue:
1
ISSN:
0004-637X
Format(s):
Medium: X Size: Article No. 47
Size(s):
["Article No. 47"]
Sponsoring Org:
National Science Foundation
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