SYSTEMATIC UNCERTAINTIES ASSOCIATED WITH THE COSMOLOGICAL ANALYSIS OF THE FIRST PAN-STARRS1 TYPE Ia SUPERNOVA SAMPLE

We probe the systematic uncertainties from the 113 Type Ia supernovae (SN Ia) in the Pan-STARRS1 (PS1) along with 197 SN Ia from a combination of low-redshift surveys. The companion paper by Rest et al. the photometric measurements and cosmological inferences from the PS1 sample. The largest systematic stems from the photometric calibration of the PS1 and low-z samples. We increase the sample of Calspec standards from 7 to 10 used to define the PS1 calibration system. The PS1 and SDSS-II systems are compared and discrepancies up to ∼0. 02 mag are recovered. We find uncertainties in the way to treat intrinsic colors and reddening produce differences in the recovered value of w up to 3%. We masses of host galaxies of PS1 supernovae and detect an insignificant difference in distance residuals of full sample of 0. 037 ± 0. 031 mag for host galaxies with high and low masses. Assuming flatness and including uncertainties in our analysis of only SNe measurements, we find w =−1. 120+0. 360 −0. 206 (Stat) +0. 269 −0. 291 (Sys). additional constraints from Baryon acoustic oscillation, cosmic microwave background (CMB) (Planck) and 0 measurements, we find w = −1. 166+0. 072 −0. 069 and Ωm = 0. 280+0. 013 −0. 012 (statistical and systematic errors added in). The significance of the inconsistency with w = −1 depends on whether we use Planck or Wilkinson Anisotropy Probe measurements of the CMB: wBAO+H0+SN+WMAP = −1. 124+0. 083 −0. 065.