PI: Patrick Kelly, Stanford University, email@example.com
Address: Physics Department, 382 Via Pueblo Mall, Stanford, CA 94305, USA
CoI: David Burke, SLAC National Accelerator Laboratory
Title: Shifting Standards: SN Ia Calibration Across Host Environments
Abstract: We propose continuing our program of imaging ~160 low-redshift Constitution SN host galaxies in \textitu'g'r'i'z' filters. Stellar masses estimated from existing SDSS imaging of 70 host galaxies reveal a systematic trend in Hubble residuals where SN Ia are ~10% brighter (after light curve correction) when they occur in more massive galaxies. Our ongoing effort will place strong constraints on a host mass- dependent trend in Hubble residuals. We additionally propose related observations of 40 low-inclination spiral host galaxies in H(alpha) to measure the separation of SN Ia explosions from nearby spiral arms. Simple models of spiral density wave propagation and resulting star formation enable the ages of `prompt' progenitors to be estimated. By identifying younger and older `prompt' SN Ia progenitors in high metallicity environments, these measurements will disentangle the effects of metallicity and age on SN Ia calibration.
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