AR 16631 (Archival Research)

Sun Jul 14 05:47:08 GMT 2024

Principal Investigator: David Rubin
PI Institution: University of Hawaii
Investigators (xml)

Title: A Blinded Photometric Reanalysis of the Cepheid Observations
Cycle: 29

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.