{"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/the-impact-of-the-cosmic-variance-on-h_0-on","title":"The impact of the cosmic variance on $H_0$ on cosmological analyses","arxiv_id":"1805.09900","date":"2018-05-24","proceeding":null,"authors":["David Camarena","Valerio Marra"],"abstract":"The current $3.8 \\sigma$ tension between local (arXiv:1804.10655) and global (arXiv:1605.02985) measurements of $H_0$ cannot be fully explained by the concordance $\\Lambda$CDM model. It could be produced by unknown systematics or by physics beyond the standard model. On the other hand, it is well known that linear perturbation theory predicts a cosmic variance on the Hubble parameter $H_0$, which leads to systematic errors on its local determination. Here, we study how including in the likelihood the cosmic variance on $H_0$ affects statistical inference. In particular we consider the $\\gamma$CDM, $w$CDM and $\\gamma w$CDM parametric extensions of the standard model, which we constrain with the latest CMB, BAO, SNe Ia, RSD and $H_0$ data. We learn two important lessons. First, the systematic error from cosmic variance is - independently of the model - approximately $\\sigma_{\\text{cv}}\\approx 0.88$ km s$^{-1}$ Mpc$^{-1}$ (1.2\\% $H_0^{\\text{loc}}$) when considering the redshift range $0.0233 \\le z \\le 0.15$, which is relative to the main analysis of (arXiv:1804.10655), and $\\sigma_{\\text{cv}}\\approx 1.5$ km s$^{-1}$ Mpc$^{-1}$ (2.1\\% $H_0^{\\text{loc}}$) when considering the wider redshift range $0.01 \\le z \\le 0.15$. Although $\\sigma_{\\text{cv}}$ affects the total error budget on local $H_0$, it does not significantly alleviate the tension which remains at $\\approx 3 \\sigma$. Second, cosmic variance, besides shifting the constraints, can change the results of model selection: much of the statistical advantage of non-standard models is to alleviate the now-reduced tension. We conclude that, when constraining non-standard models it is important to include the cosmic variance on $H_0$ if one wants to use the local determination of the Hubble constant by Riess et al. (arXiv:1804.10655). Doing the contrary could potentially bias the conclusions.","url_abs":"http://arxiv.org/abs/1805.09900v2","url_pdf":"http://arxiv.org/pdf/1805.09900v2.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":"the-impact-of-the-cosmic-variance-on-h_0-on","repo_url":"https://github.com/valerio-marra/mBayes","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}