0 Assigned ID: 2530 ----- Attempting Submission 1 (Sat Apr 10 01:56:08 GMT 2021) ----- Tension in the value of the Hubble constant (H0) between early universe measurements and late-universe (local) measurements is the largest source of controversy in cosmology today. The tension posed between the early and late universe would have profound implications for new physics---if it is confirmed. To confirm this tension, we need crosschecks and independent analyses, particularly at the (difficult and less often checked) level of photometry. We propose a pixel-level, blinded reanalysis of the WFC3 Cepheid data, which becomes severely crowed at tens of Mpc distances. Instead of resampling each dither to a common frame, we will model the original WFC3 pixels directly, thus yielding no loss of information and well-understood pixel-level uncertainties. Futuremore, we will infer a probabilistic catalog of sources around each Cepheid, which has been shown to outperform traditional techniques in crowded fields. This project, if funded, will thus be able to confirm or reject the tension between the early and late universe. David Rubin is an Assistant Professor at the University of Hawai`i at Manoa. He has recently written a highly accurate (~ 0.1%) forward-modeling photometry code for use in undersampled SN observations, recently deployed in Hayden, Rubin, Boone et al., (2021) and Rubin, Cikota et al., (2021). He has additional experience in Bayesian inference, having created the Unified Nonlinear Inference for Type Ia cosmologY framework (Rubin et al. 2015). He has published HST photometry using NICMOS, ACS, and WFC3. He will work with a graduate student to complete this project. Large Scale Structure of the Universe Stellar Populations and the Interstellar Medium 0 Regular false false false false false SUPPORTED