{"about":{"site":"https://codewithpapers.app","non_affiliation":"Code with Papers and Syntology are not affiliated with, endorsed by, or sponsored by Papers with Code, Meta, or the pwc-archive mirror.","licence":"CC BY-SA 4.0","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","attribution":"https://codewithpapers.app/attribution","modified":"archive material modified by Syntology; see the attribution page"},"url":"/paper/new-constraints-on-the-expansion-rate-at","title":"Constraints on the cosmic expansion rate at redshift 2.3 from the Lyman-$α$ forest","arxiv_id":"2209.13942","date":"2022-09-28","proceeding":null,"authors":["Andrei Cuceu","Andreu Font-Ribera","Seshadri Nadathur","Benjamin Joachimi","Paul Martini"],"abstract":"We determine the product of the expansion rate and angular-diameter distance at redshift $z=2.3$ from the anisotropy of Lyman-$\\alpha$ (Ly$\\alpha$) forest correlations measured by the Sloan Digital Sky Survey (SDSS). Our result is the most precise from large-scale structure at $z>1$. In flat $\\Lambda$CDM we determine the matter density to be $\\Omega_\\mathrm{m}=0.36^{+0.03}_{-0.04}$ from Ly$\\alpha$ alone. This is a factor of two tighter than baryon acoustic oscillation results from the same data due to our use of a wide range of scales ($25<r<180$ $h^{-1}\\text{Mpc}$). Using a nucleosynthesis prior, we measure the Hubble constant to be $H_0=63.2\\pm2.5$ km/s/Mpc. In combination with other SDSS tracers, we find $H_0=67.2\\pm0.9$ km/s/Mpc and measure the dark energy equation-of-state parameter to be $w=-0.90\\pm0.12$. Our work opens a new avenue for constraining cosmology at high redshift.","url_abs":"https://arxiv.org/abs/2209.13942v2","url_pdf":"https://arxiv.org/pdf/2209.13942v2.pdf","source":{"archive":"pwc-archive (Hugging Face), CC BY-SA 4.0","snapshot":"2025-07-28","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","row_kind":"links_only","authors_date_abstract":"arXiv metadata, CC0 1.0 (https://info.arxiv.org/help/license), from the Kaggle arXiv metadata snapshot of 2026-09-12"},"code_links":[{"paper_slug":"new-constraints-on-the-expansion-rate-at","repo_url":"https://github.com/andreicuceu/cobaya_likelihoods","is_official":1,"mentioned_in_paper":1,"mentioned_in_github":1,"framework":"none","reach":null}],"tasks":[],"methods":[],"datasets_introduced":[],"methods_introduced":[],"results":[],"syntology":{"syntology_url":null,"atlas_url":null,"mcp":null,"developers":"https://syntology.ai/developers"},"arxiv_metadata":null,"syntology_extracted_results":null}