Quantitative comparison between Type Ia supernova spectra at low and high redshifts: A case study
/ Authors
G. Garavini, G. Garavini, G. Folatelli, S. Nobili, G. Aldering, R. Amanullah, P. Antilogus, P. Astier, G. Blanc, T. Bronder
and 42 more authors
M. Burns, A. Conley, A. Conley, S. Deustua, M. Doi, S. Fabbro, V. Fadeyev, R. Gibbons, G. Goldhaber, G. Goldhaber, A. Goobar, D. Groom, I. Hook, D. Howell, N. Kashikawa, A. Kim, M. Kowalski, N. Kuznetsova, Brian C. Lee, C. Lidman, J. Méndez, T. Morokuma, K. Motohara, P. Nugent, R. Pain, S. Perlmutter, S. Perlmutter, R. Quimby, J. Raux, N. Regnault, P. Ruiz-Lapuente, G. Sainton, K. Schahmaneche, E. Smith, A. Spadafora, V. Stanishev, R. Thomas, N. Walton, Lifan Wang, W. M. Wood-Vasey, W. M. Wood-Vasey, N. Yasuda
/ Abstract
We develop a method to measure the strength of the absorption features in Type Ia supernova (SN Ia) spectra and use it to make a quantitative comparison between the spectra of Type Ia supernovae at low and high redshifts. In this case study, we apply the method to 12 high-redshift (0.212 ≤ z ≤ 0.912) SNe Ia observed by the Supernova Cosmology Project . Through measurements of the strengths of these features and of the blueshift of the absorption minimum in Ca ii H&K, we show that the spectra of the high-redshift SNe Ia are quantitatively similar to spectra of nearby SNe Ia (z < 0.15). One supernova in our high redshift sample, SN 2002fd at z=0.279, is found to have spectral characteristics that are associated with peculiar SN 1991T/SN 1999aa-like supernovae.
Journal: Astronomy and Astrophysics