Cosmological parameter uncertainties from salt-II type IA supernova light curve models

J. Mosher, J. Guy, R. Kessler, P. Astier, J. Marriner, M. Betoule, M. Sako, P. El-Hage, R. Biswas, R. Pain, S. Kuhlmann, N. Regnault, J. A. Frieman, D. P. Schneider

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62 Scopus citations


We use simulated type Ia supernova (SN Ia) samples, including both photometry and spectra, to perform the first direct validation of cosmology analysis using the SALT-II light curve model. This validation includes residuals from the light curve training process, systematic biases in SN Ia distance measurements, and a bias on the dark energy equation of state parameter w. Using the SN-analysis package SNANA, we simulate and analyze realistic samples corresponding to the data samples used in the SNLS3 analysis: ∼120 low-redshift (z < 0.1) SNe Ia, ∼255 Sloan Digital Sky Survey SNe Ia (z < 0.4), and ∼290 SNLS SNe Ia (z ≤ 1). To probe systematic uncertainties in detail, we vary the input spectral model, the model of intrinsic scatter, and the smoothing (i.e., regularization) parameters used during the SALT-II model training. Using realistic intrinsic scatter models results in a slight bias in the ultraviolet portion of the trained SALT-II model, and w biases (w input-w recovered) ranging from -0.005 ± 0.012 to -0.024 ± 0.010. These biases are indistinguishable from each other within the uncertainty; the average bias on w is -0.014 ± 0.007.

Original languageEnglish (US)
Article number16
JournalAstrophysical Journal
Issue number1
StatePublished - Sep 20 2014

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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