UC Berkeley

The Hubble tension is, at this time, the singular most overwhelming problem in cosmology. Core-collapse Type IIP supernovae (SNe IIP) offer an independent probe of extragalactic distances and are therefore well-positioned to contribute to resolving this discrepancy. What follows is an investigation into two methods using the largest Type IIP SNe dataset to date to compute their distances. First, we calibrate 28 SNe from the Zwicky Transient Facility (ZTF) together with 39 additional SNe IIP from the literature using the standard candle method (SCM). We determine an intrinsic uncertainty of σint = 0.26 mag on the method, or a 12% error in distance, which is comparable to other SNe IIP SCM studies. We then use 9 calibrators from host galaxies of SNe IIP to constrain the absolute magnitude M of our sample, and determine H0 = 70.2±5.9 km s−1 Mpc−1 with an intrinsic uncertainty of σint = 0.25 mag. This result is consistent with both local- and late-universe measurements of H0 by Planck and SH0ES, but does not clearly favor either owing to our wide uncertainties. Finally, we calibrate 46 SNe IIP from ZTF and 6 SNe IIP from the Sloan Digital Sky Survey (SDSS) using the photometric candle method (PCM). However, our sample suffers significantly from bias, yielding an intrinsic uncertainty of σint = 0.28 mag, making a measurement of H0 impossible at this time. While not yet competitive with SNe Ia precision for cosmological distances, next-generation, large-scale surveys like the Vera C. Rubin Observatory and Nancy Grace Roman Space Telescope will position SNe IIP to contribute competitive, independent constraints on H0 through reduced uncertainties and larger sample sizes.