{"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/bayesian-constraints-on-the-global-21-cm","title":"Bayesian constraints on the global 21-cm signal from the Cosmic Dawn","arxiv_id":"1606.06006","date":"2016-06-20","proceeding":null,"authors":["G. Bernardi","J. T. L. Zwart","D. Price","L. J. Greenhill","A. Mesinger","J. Dowell","T. Eftekhari","S. W. Ellingson","J. Kocz","F. Schinzel"],"abstract":"The birth of the first luminous sources and the ensuing epoch of reionization are best studied via the redshifted 21-cm emission line, the signature of the first two imprinting the last. In this work we present a fully-Bayesian method, \\textsc{hibayes}, for extracting the faint, global (sky-averaged) 21-cm signal from the much brighter foreground emission. We show that a simplified (but plausible), Gaussian model of the 21-cm emission from the Cosmic Dawn epoch ($15 \\lesssim z \\lesssim 30$), parameterized by an amplitude $A_{\\rm HI}$, a frequency peak $\\nu_{\\rm HI}$ and a width $\\sigma_{\\rm HI}$, can be extracted even in the presence of a structured foreground frequency spectrum (parameterized as a $7^{\\rm th}$-order polynomial), provided sufficient signal-to-noise (400~hours of observation with a single dipole). We apply our method to an early, 19-minute long observation from the Large aperture Experiment to detect the Dark Ages, constraining the 21-cm signal amplitude and width to be $-890 < A_{\\rm HI} < 0$ mK and $\\sigma_{\\rm HI} > 6.5$ MHz (corresponding to $\\Delta z > 1.9$ at redshift $z \\simeq 20$) respectively at the 95-per-cent confidence level in the range $13.2 < z < 27.4$ ($100 > \\nu > 50$ MHz).","url_abs":"http://arxiv.org/abs/1606.06006v1","url_pdf":"http://arxiv.org/pdf/1606.06006v1.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":"bayesian-constraints-on-the-global-21-cm","repo_url":"https://github.com/ska-sa/hibayes","is_official":1,"mentioned_in_paper":1,"mentioned_in_github":0,"framework":"none","reach":null}],"tasks":[],"methods":[],"datasets_introduced":[],"methods_introduced":[],"results":[],"syntology":{"atlas_url":null,"mcp":null,"developers":"https://syntology.ai/developers"},"arxiv_metadata":null,"syntology_extracted_results":null}