{"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-role-of-galaxies-and-agn-in-reionizing","title":"The role of galaxies and AGN in reionizing the IGM - II: metal-tracing the faint sources of reionization at $5\\lesssim z\\lesssim6$","arxiv_id":"1807.07899","date":"2018-07-20","proceeding":null,"authors":["Romain A. Meyer","Sarah E. I. Bosman","Koki Kakiichi","Richard S. Ellis"],"abstract":"We present a new method to study the contribution of faint sources to the UV background using the 1D correlation of metal absorbers with the intergalactic medium (IGM) transmission in a Quasi Stellar Object (QSO) sightline. We take advantage of a sample of $25$ high signal-to-noise ratio QSO spectra to retrieve $150$ triply-ionised carbon (\\cfour) absorbers at $4.5\\lesssim z\\lesssim 6.2$, of which $37$ systems whose expected H{~\\small I} absorption lie in the Lyman-$\\alpha$ forest. We derive improved constraints on the cosmic density of \\cfour \\,at $4.3< z < 6.2$ and infer from abundance-matching that \\cfour \\,absorbers trace $M_{\\text{UV}}\\lesssim -16$ galaxies. Correlation with the Lyman-$\\alpha$ forest of the QSOs indicates that these objects are surrounded by a highly opaque region at $r\\lesssim 5 $ cMpc/h followed by an excess of transmission at $r\\gtrsim 10$ cMpc/h detected at $2.7\\sigma$. This is in contrast to equivalent measurements at lower redshifts where only the opaque trough is detected. We interpret this excess as a statistical enhancement of the local photoionisation rate due to clustered faint galaxies around the \\cfour \\,absorbers. Using the analytical framework described in Paper I of this series, we derive a constraint on the average product of the escape fraction and the Lyman continuum photon production efficiency of the galaxy population clustered around the \\cfour \\,absorbers, $\\log \\langle f_{\\text{esc}}\\xi_{\\text{ion}}\\rangle /[{\\rm erg^{-1}~Hz}] = 25.01^{+0.30}_{-0.19}$. This implies that faint galaxies beyond the reach of current facilities may have harder radiation fields and/or larger escape fractions than currently detected objects at the end of the reionisation epoch.","url_abs":"http://arxiv.org/abs/1807.07899v1","url_pdf":"http://arxiv.org/pdf/1807.07899v1.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-role-of-galaxies-and-agn-in-reionizing","repo_url":"https://github.com/rameyer/QUICFit","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}