2020/09/30 by Levon Pogosian, Gong-Bo Zhao, Karsten Jedamzik · 1 citation
Physics and Astronomy · #Astrophysical Phenomena and Observations #Baryon #Baryon acoustic oscillations #Cosmic microwave background #Cosmology and Gravitation Theories #Dark energy #Decoupling (probability) #Galaxy #Hubble's law #Planck #Pulsars and Gravitational Waves Research #astro-ph.CO
paper · pdf · doi:10.3847/2041-8213/abc6a8
8 pages, 4 figures, 2 tables; v2: minor revisions, references added, matches the version accepted to Ap J Lett
openalex created_date 2020/09/21 · arxiv created 2020/11/02 · openalex publication_date 2020/11/25 · arxiv updated 2020/11/26 · openalex updated_date 2026/08/06
Abstract The Hubble tension and attempts to resolve it by modifying the physics of (or at) recombination motivate finding ways to determine H 0 and the sound horizon at the epoch of baryon decoupling r d in ways that rely neither on a recombination model nor on late-time Hubble data. In this work, we investigate what one can learn from the current and future BAO data when treating r d and H 0 as independent free parameters. It is well known that baryon acoustic oscillations (BAOs) give exquisite constraints on the product r d H 0 . We show here that imposing a moderate prior on Ω m h 2 breaks the degeneracy between r d and H 0 . Using the latest BAO data, including the recently released the extended Baryon Oscillation Spectroscopic Survey Data Release 16, along with a Ω m h 2 prior based on the Planck best-fit Λ cold dark matter (ΛCDM) model, we find r d = 143.7 ± 2.7 Mpc and H 0 = 69.6 ± 1.8 km s −1 Mpc −1 . BAO data prefers somewhat lower r d and higher H 0 than those inferred from Planck data in a ΛCDM model. We find similar values when combing BAO with the Pantheon supernovae, the Dark Energy Survey Year 1 galaxy weak lensing, Planck or SPTPol cosmic microwave background lensing, and the cosmic chronometer data. We perform a forecast for the Dark Energy Spectroscopic Instrument (DESI) and find that, when aided with a moderate prior on Ω m h 2 , DESI will measure r d and H 0 without assuming a recombination model with an accuracy surpassing the current best estimates from Planck.