skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The rise times of low and high redshift type Ia supernovae are consistent

Abstract

We present a self-consistent comparison of the rise times for low- and high-redshift Type Ia supernovae. Following previous studies, the early light curve is modeled using a t2 law, which is then mated with a modified Leibundgut template light curve. The best-fit t2 law is determined for ensemble samples of low- and high-redshift supernovae by fitting simultaneously for all lightcurve parameters for all supernovae in each sample. Our method fully accounts for the non-negligible covariance amongst the light curve fitting parameters, which previous analyses have neglected. Contrary to Riess et al. (1999a), we find fair to good agreement between the rise times of the low and high-redshift Type Ia supernovae. The uncertainty in the rise time of the high-redshift Type Ia supernovae is presently quite large (roughly + or - 1.5 days statistical), making any assertion of evolution based on a comparison of rise times premature. Furthermore, systematic effects on rise time determinations from th e high-redshift observations, due to the form of the late-time light curve and the manner in which the light curves of these supernovae were sampled, can bias the high-redshift rise time determinations by up to +1.5 or -2.2 days under extreme situations. The peak brightnessesmore » - used for cosmology - do not suffer any significant bias.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab., CA (US)
Sponsoring Org.:
USDOE Director, Office of Science. Office of High Energy and Nuclear Physics. Division of High Energy Physics (US)
OSTI Identifier:
771730
Report Number(s):
LBNL-44232
Journal ID: ISSN 0004-6256; ANJOAA; R&D Project: 419401; TRN: AH200104%%534
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Journal Article
Journal Name:
Astronomical Journal
Additional Journal Information:
Journal Volume: 119; Journal Issue: 5; Other Information: PBD: 14 Sep 1999; Journal ID: ISSN 0004-6256
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COSMOLOGY; PULSE RISE TIME; SUPERNOVAE

Citation Formats

Aldering, Greg, Knop, Robert, Nugent, Peter, and Perlmutter, Saul. The rise times of low and high redshift type Ia supernovae are consistent. United States: N. p., 1999. Web.
Aldering, Greg, Knop, Robert, Nugent, Peter, & Perlmutter, Saul. The rise times of low and high redshift type Ia supernovae are consistent. United States.
Aldering, Greg, Knop, Robert, Nugent, Peter, and Perlmutter, Saul. Tue . "The rise times of low and high redshift type Ia supernovae are consistent". United States.
@article{osti_771730,
title = {The rise times of low and high redshift type Ia supernovae are consistent},
author = {Aldering, Greg and Knop, Robert and Nugent, Peter and Perlmutter, Saul},
abstractNote = {We present a self-consistent comparison of the rise times for low- and high-redshift Type Ia supernovae. Following previous studies, the early light curve is modeled using a t2 law, which is then mated with a modified Leibundgut template light curve. The best-fit t2 law is determined for ensemble samples of low- and high-redshift supernovae by fitting simultaneously for all lightcurve parameters for all supernovae in each sample. Our method fully accounts for the non-negligible covariance amongst the light curve fitting parameters, which previous analyses have neglected. Contrary to Riess et al. (1999a), we find fair to good agreement between the rise times of the low and high-redshift Type Ia supernovae. The uncertainty in the rise time of the high-redshift Type Ia supernovae is presently quite large (roughly + or - 1.5 days statistical), making any assertion of evolution based on a comparison of rise times premature. Furthermore, systematic effects on rise time determinations from th e high-redshift observations, due to the form of the late-time light curve and the manner in which the light curves of these supernovae were sampled, can bias the high-redshift rise time determinations by up to +1.5 or -2.2 days under extreme situations. The peak brightnesses - used for cosmology - do not suffer any significant bias.},
doi = {},
journal = {Astronomical Journal},
issn = {0004-6256},
number = 5,
volume = 119,
place = {United States},
year = {1999},
month = {9}
}