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arXiv · 1104.2874

Type Ia supernova parameter estimation: a comparison of two approaches using current datasets

B. L. Lago·M. O. Calvão·S. E. Jorás·R. R. R. Reis·I. Waga·R. Giostri
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Abstract

By using the Sloan Digital Sky Survey (SDSS) first year type Ia supernova (SN Ia) compilation, we compare two different approaches (traditional χ^2 and complete likelihood) to determine parameter constraints when the magnitude dispersion is to be estimated as well. We consider cosmological constant + Cold Dark Matter (ΛCDM) and spatially flat, constant w Dark Energy + Cold Dark Matter (FwCDM) cosmological models and show that, for current data, there is a small difference in the best fit values and $\sim$ 30% difference in confidence contour areas in case the MLCS2k2 light-curve fitter is adopted. For the SALT2 light-curve fitter the differences are less significant ($\lesssim$ 13% difference in areas). In both cases the likelihood approach gives more restrictive constraints. We argue for the importance of using the complete likelihood instead of the χ^2 approach when dealing with parameters in the expression for the variance.

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B. L. Lago, M. O. Calvão, S. E. Jorás, R. R. R. Reis, I. Waga, R. Giostri. 2011-10-26. Type Ia supernova parameter estimation: a comparison of two approaches using current datasets. https://doi.org/10.1051/0004-6361%2F201118599

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