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arXiv · astro-ph/9707260

Time Dilation from Spectral Feature Age Measurements of Type Ia Supernovae

A. G. Riess·A. V. Filippenko·D. C. Leonard·B. P. Schmidt·N. Suntzeff·M. M. Phillips·R. Schommer·A. Clocchiatti·R. P. Kirshner·P. Garnavich·P. Challis·B. Leibundgut·J. Spyromilio·R. C. Smith
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Abstract

We have developed a quantitative, empirical method for estimating the age of Type Ia supernovae (SNe Ia) from a single spectral epoch. The technique examines the goodness of fit of spectral features as a function of the temporal evolution of a large database of SNe Ia spectral features. When a SN Ia spectrum with good signal-to-noise ratio over the rest frame range 3800 to 6800 A is available, the precision of a spectral feature age (SFA) is (1-sigma) ~ 1.4 days. SFA estimates are made for two spectral epochs of SN 1996bj (z=0.574) to measure the rate of aging at high redshift. In the 10.05 days which elapsed between spectral observations, SN 1996bj aged 3.35 $\pm$ 3.2 days, consistent with the 6.38 days of aging expected in an expanding Universe and inconsistent with no time dilation at the 96.4 % confidence level. The precision to which individual features constrain the supernova age has implications for the source of inhomogeneities among SNe Ia.

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A. G. Riess, A. V. Filippenko, D. C. Leonard, B. P. Schmidt, N. Suntzeff, M. M. Phillips, R. Schommer, A. Clocchiatti, R. P. Kirshner, P. Garnavich, P. Challis, B. Leibundgut, J. Spyromilio, R. C. Smith. 1997-07-24. Time Dilation from Spectral Feature Age Measurements of Type Ia Supernovae. https://doi.org/10.1086/118506

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