Description
Perhaps the most pressing problem in current cosmology is the cause of the Hubble tension. We revisit a two-rung distance ladder, composed only of Cepheid periods and magnitudes, anchor distances in the Milky Way, Large Magellanic Cloud and NGC 4258, and host galaxy redshifts. Following Kenworthy et al. 2022, for the most accurate and up-to-date measurements, we adopt the SH0ES data, where the Cepheid hosts were selected (incidentally) to harbour also Type Ia supernovae. Unlike Kenworthy et al., we find this data to yield $H_0 = 68.6 \pm 1.5$ km/s/Mpc in our fiducial model, fully consistent with Planck and in tension with the SH0ES result. We show that our results are robust to selection function and peculiar velocity modelling. We isolate the cause of the difference in biases in Kenworthy et al.'s analysis pipeline and conclude that local data in fact argues against a Hubble tension. This suggests problems in the full SH0ES analysis, and implies that a highly precise Hubble constant measurement is achievable using second-rung data alone (e.g. completely excluding supernovae).
