期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 463, 期 4, 页码 4311-4316出版社
OXFORD UNIV PRESS
DOI: 10.1093/mnras/stw2278
关键词
methods: data analysis; methods: statistical; supernovae: general; distance scale
资金
- Science and Technology Facilities Council (UK) [ST/N000838/1]
- EPSRC 'Pathways to Impact' grant
- Wolfson Research Merit Award by the British Royal Society [WM110023]
- Marie-Curie Career Integration grant by European Commission [FP7-PEOPLE-2012-CIG-321865]
- European Commission [H2020-MSCA-RISE-2015-691164]
- Science and Technology Facilities Council [ST/N000838/1, ST/K001051/1] Funding Source: researchfish
- STFC [ST/N000838/1, ST/K001051/1] Funding Source: UKRI
Accurate standardization of Type Ia supernovae (SNIa) is instrumental to the usage of SNIa as distance indicators. We analyse a homogeneous sample of 22 low-z SNIa, observed by the Carnegie Supernova Project in the optical and near-infrared (NIR). We study the time of the second peak in the J band, t(2), as an alternative standardization parameter of SNIa peak optical brightness, as measured by the standard SALT2 parameter m(B). We use BAHAMAS, a Bayesian hierarchical model for SNIa cosmology, to estimate the residual scatter in the Hubble diagram. We find that in the absence of a colour correction, t(2) is a better standardization parameter compared to stretch: t(2) has a 1 sigma posterior interval for the Hubble residual scatter of sigma(Delta mu) = {0.250, 0.257} mag, compared to sigma(Delta mu) = {0.280, 0.287} mag when stretch (x(1)) alone is used. We demonstrate that when employed together with a colour correction, t(2) and stretch lead to similar residual scatter. Using colour, stretch and t(2) jointly as standardization parameters does not result in any further reduction in scatter, suggesting that t(2) carries redundant information with respect to stretch and colour. With a much larger SNIa NIR sample at higher redshift in the future, t(2) could be a useful quantity to perform robustness checks of the standardization procedure.
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