1. The Dark Energy Survey Supernova Program: slow supernovae show cosmological time dilation out to z ~ 1.
- Author
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White, R M T, Davis, T M, Lewis, G F, Brout, D, Galbany, L, Glazebrook, K, Hinton, S R, Lee, J, Lidman, C, Möller, A, Sako, M, Scolnic, D, Smith, M, Sullivan, M, Sánchez, B O, Shah, P, Vincenzi, M, Wiseman, P, Abbott, T M C, and Aguena, M
- Subjects
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TYPE I supernovae , *TIME dilation , *LIGHT curves , *DARK energy , *SUPERNOVAE - Abstract
We present a precise measurement of cosmological time dilation using the light curves of 1504 Type Ia supernovae from the Dark Energy Survey spanning a redshift range |$0.1\lesssim z\lesssim 1.2$|. We find that the width of supernova light curves is proportional to |$(1+z)$| , as expected for time dilation due to the expansion of the Universe. Assuming Type Ia supernovae light curves are emitted with a consistent duration |$\Delta t_{\rm em}$| , and parametrizing the observed duration as |$\Delta t_{\rm obs}=\Delta t_{\rm em}(1+z)^b$| , we fit for the form of time dilation using two methods. First, we find that a power of |$b \approx 1$| minimizes the flux scatter in stacked subsamples of light curves across different redshifts. Secondly, we fit each target supernova to a stacked light curve (stacking all supernovae with observed bandpasses matching that of the target light curve) and find |$b=1.003\pm 0.005$| (stat) |$\pm \, 0.010$| (sys). Thanks to the large number of supernovae and large redshift-range of the sample, this analysis gives the most precise measurement of cosmological time dilation to date, ruling out any non-time-dilating cosmological models at very high significance. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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