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تسجيل مستخدم جديدThe Dependence of the Type Ia Supernova Host Bias on Observation or Fitting Technique
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Brighter type Ia supernovae (SNe Ia) prefer less massive hosts with higher star formation. This bias is over-corrected for SNe Ia standardized using the standard Tripp relation, resulting in a step-like dependence of standardized distance on host properties. Using the PISCO supernova host sample and SDSS, GALEX, and 2MASS photometry, we compare host galaxy stellar mass and star formation rate (SFR) estimates from different observation and fitting techniques and their impact on the mass step and sSFR step biases. The step size for FAST++ mass estimates was $-0.04pm0.02$ mag for FAST++ and STARLIGHT, increasing by 0.02 mag for ZPEG. UV information had no effect on measured mass step size or location. Our small sample sizes resulted in all mass step size uncertainties being within 2$sigma$ significance of a zero step due. Regardless, mass step sizes were all consistently within 1$sigma$ of each other. Specific SFR (sSFR) step sizes are $0.05pm0.03$ mag (H$alpha$) and $0.06pm0.03$ mag (UV) for a reduced 51 host sample with SDSS and GALEX coverage, with 50% increase in step size uncertainties. Step location was determined by mass sample used to normalize sSFR. The step size reduces by 0.04 mag with an unconstrained location using all available 73 hosts with H$alpha$ measurements. Despite reduced sample sizes, we find no evidence that observation or fitting technique choice drives mass step measurement, but cannot conclude the same for the sSFR step. Further work will focus on differing star formation epochs and dust attenuation corrections effects on the sSFR bias.
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