0 Assigned ID: 3763 ----- Attempting Submission 1 (Fri Mar 25 23:56:42 GMT 2022) ----- Type Ia supernovae are important distance indicators for cosmology, however the neither the exact progenitor system nor the relative rates of different progenitor systems for these supernovae are well known. Important observational differences exist between the two main progenitor types - single-degenerate systems are expected to exhibit more dust than double-degenerate systems on account of the accretion disk. One way to illuminate the dust around type Ia supernovae is to search for light echoes: transient reflection nebulae created by dust scattering light into our line of sight. In order to obtain the most complete information from light echoes, they need to be resolved. Therefore, we are limited to the closest type Ia supernovae for our search. The most recent SH0ES analysis of 42 type Ia supernovae (Riess et al. 2021) provides a natural sample for a light echo search, as the archival data is in the correct filters and targets nearby star-forming supernova host galaxies with plenty of dust. We propose to analyze the SH0ES archival data and additional data from other proposals to identify new light echoes around type Ia supernovae and then use those light echoes to map the dust distributions, constrain the progenitors, and constrain the dust properties of the host galaxy. Our team has extensive experience with supernovae, supernova remnants and light echoes, and is similarly accomplished with the planning and execution of HST observations, data reductions, and PSF-matched difference imaging. Co-I Garnavich has been PI on 15 successful HST programs and Co-I on 62 more and Co-I Lawrence has been PI on 4 HST programs and Co-I on 38. Co-I Garnavich has been first-author on 9 and co-author on more than 150 peer-reviewed articles, many involving HST data analysis, supernovae, and light echoes. Co-I Lawrence has been first-author or co-author on 21 similar articles. Co-I Garnavich is also involved with supernovae and light echo research on other large projects, including Kelper/K2. PI Wood is a graduate student (soon to be postdoc) concentrating on supernova light echoes, is first-author on 1 article and co-author on 3 articles. Stellar Populations and the Interstellar Medium Stellar Physics and Stellar Types 0 Regular false false false false false false SUPPORTED