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Comparative Direct Analysis of Type Ia Supernova Spectra. II. Maximum Light

David Branch·Leeann Chau Dang·Nicholas Hall·Wesley Ketchum·Mercy Melakayil·Jerod Parrent·M. A. Troxel·D. Casebeer·David J. Jeffery·E. Baron
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Abstract

A comparative study of near-maximum-light optical spectra of 24 Type Ia supernovae (SNe Ia) is presented. The spectra are quantified in two ways, and assigned to four groups. Seven "core-normal" SNe Ia have very similar spectra, except for strong high-velocity CaII absorption in SN 2001el. Seven SNe Ia are assigned to a "broad-line" group, the most extreme of which is SN 1984A. Five SNe Ia, including SN 1991bg, are assigned to a "cool" group. Five SNe Ia, including SN 1991T, are assigned to a "shallow-silicon" group. Comparisons with SYNOW synthetic spectra provide a basis for discussion of line identifications, and an internally consistent quantification of the maximum-light spectroscopic diversity among SNe Ia. The extent to which SN Ia maximum-light spectra appear to have a continuous distribution of properties, rather than consisting of discrete subtypes, is discussed.

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David Branch, Leeann Chau Dang, Nicholas Hall, Wesley Ketchum, Mercy Melakayil, Jerod Parrent, M. A. Troxel, D. Casebeer, David J. Jeffery, E. Baron. 2006-01-03. Comparative Direct Analysis of Type Ia Supernova Spectra. II. Maximum Light. https://doi.org/10.1086/502778

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