Constraining Cosmic Evolution of Type Ia Supernovae

Journal Article · Wed Feb 13 00:00:00 EST 2008 · Astrophysical Journal

DOI:https://doi.org/10.1086/589612· OSTI ID:923765

Foley, Ryan J; Filippenko, Alexei V; Aguilera, C; Becker, A C; Blondin, S; Challis, P; Clocchiatti, A; Covarrubias, R; Davis, T M; Garnavich, P M; Jha, S; Kirshner, R P; Krisciunas, K; Leibundgut, B; Li, W; Matheson, T; Miceli, A; Miknaitis, G; Pignata, G; Rest, A ; Riess, A G

We present the first large-scale effort of creating composite spectra of high-redshift type Ia supernovae (SNe Ia) and comparing them to low-redshift counterparts. Through the ESSENCE project, we have obtained 107 spectra of 88 high-redshift SNe Ia with excellent light-curve information. In addition, we have obtained 397 spectra of low-redshift SNe through a multiple-decade effort at Lick and Keck Observatories, and we have used 45 ultraviolet spectra obtained by HST/IUE. The low-redshift spectra act as a control sample when comparing to the ESSENCE spectra. In all instances, the ESSENCE and Lick composite spectra appear very similar. The addition of galaxy light to the Lick composite spectra allows a nearly perfect match of the overall spectral-energy distribution with the ESSENCE composite spectra, indicating that the high-redshift SNe are more contaminated with host-galaxy light than their low-redshift counterparts. This is caused by observing objects at all redshifts with similar slit widths, which corresponds to different projected distances. After correcting for the galaxy-light contamination, subtle differences in the spectra remain. We have estimated the systematic errors when using current spectral templates for K-corrections to be {approx}0.02 mag. The variance in the composite spectra give an estimate of the intrinsic variance in low-redshift maximum-light SN spectra of {approx}3% in the optical and growing toward the ultraviolet. The difference between the maximum-light low and high-redshift spectra constrain SN evolution between our samples to be < 10% in the rest-frame optical.

• Research Organization: SLAC National Accelerator Lab., Menlo Park, CA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 923765
• Report Number(s): SLAC-PUB-13123; ASJOAB; arXiv:0710.2338; TRN: US200804%%1397
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal; ISSN 0004-637X
• Country of Publication: United States
• Language: English

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71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
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DISTRIBUTION
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SUPERNOVAE
ULTRAVIOLET SPECTRA
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ASTRO