Cosmological Tests with the Joint Lightcurve Analysis
  We examine whether a comparison between wCDM and R_h=ct using merged Type Ia
SN catalogs produces results consistent with those based on a single
homogeneous sample. Using the Betoule et al. (2014) joint lightcurve analysis
(JLA) of a combined sample of 613 events from SNLS and SDSS-II, we estimate the
parameters of the two models and compare them. We find that the improved
statistics can alter the model selection in some cases, but not others. In
addition, based on the model fits, we find that there appears to be a lingering
systematic offset of ~0.04-0.08 mag between the SNLS and SDSS-II sources, in
spite of the cross-calibration in the JLA. Treating wCDM, LCDM and R_h=ct as
separate models, we find in an unbiased pairwise statistical comparison that
the Bayes Information Criterion (BIC) favors the R_h=ct universe with a
likelihood of 82.8% versus 17.2% for wCDM, but the ratio of likelihoods is
reversed (16.2% versus 83.8%) when w_de=-1 (i.e., LCDM) and strongly reversed
(1.0% versus 99.0%) if in addition k=0 (i.e., flat LCDM). We point out,
however, that the value of k is a measure of the net energy (kinetic plus
gravitational) in the Universe and is not constrained theoretically, though
some models of inflation would drive k to 0 due to an expansion-enforced
dilution. Since we here consider only the basic LCDM model, the value of k
needs to be measured and, therefore, the pre-assumption of flatness introduces
a significant bias into the BIC.
