SALT2 parameters and distances for SNe

Of the 226 low-z SNe Ia in our sample, 91 objects are from LOSS, including 45 without previously published distances. Assuming a flat Universe, we find that the best fit for the dark energy equation-of-state parameter w=-0.86^+0.13^_-0.16_(stat)+/-0.11(sys) from SNe alone, consistent with a cosmological constant. Our data prefer a Universe with an accelerating rate of expansion with 99.999% confidence.

When looking at Hubble residuals as a function of host-galaxy morphology, we do not see evidence for a significant trend, although we find a somewhat reduced scatter in Hubble residuals from SNe residing within a projected distance <10kpc of the host-galaxy nucleus ({sigma}=0.156mag). Similar to the results of Blondin, Mandel and Kirshner and Silverman et al. (2012AJ....143..126B, Cat. J/AJ/143/126), we find that Hubble residuals do not correlate with the expansion velocity of SiII{lambda}6355 measured in optical spectra near maximum light.

Our data are consistent with no presence of a local "Hubble bubble". Improvements in cosmological analyses within low-z samples can be achieved by better constraining calibration uncertainties in the zero-points of photometric systems.