{"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/cosmic-reionization-and-the-21-cm-signal","title":"Cosmic Reionization and the 21-cm signal: Comparison between an analytical model and a simulation","arxiv_id":"0708.2424","date":"2007-08-20","proceeding":null,"authors":["Mario G. Santos","Alexandre Amblard","Jonathan Pritchard","Hy Trac","Renyue Cen","Asantha Cooray"],"abstract":"We measure several properties of the reionization process and the\ncorresponding low-frequency 21-cm signal associated with the neutral hydrogen\ndistribution, using a large volume, high resolution simulation of cosmic\nreionization. The brightness temperature of the 21-cm signal is derived by\npost-processing this numerical simulation with a semi-analytical prescription.\nOur study extends to high redshifts (z ~ 25) where, in addition to collisional\ncoupling, our post-processed simulations take into account the inhomogeneities\nin the heating of the neutral gas by X-rays and the effect of an inhomogeneous\nLya radiation field. Unlike the well-studied case where spin temperature is\nassumed to be significantly greater than the temperature of the cosmic\nmicrowave background due to uniform heating of the gas by X-rays, spatial\nfluctuations in both the Lya radiation field and X-ray intensity impact\npredictions related to the brightness temperature at z > 10, during the early\nstages of reionization and gas heating. The statistics of the 21-cm signal from\nour simulation are then compared to existing analytical models in the\nliterature and we find that these analytical models provide a reasonably\naccurate description of the 21-cm power spectrum at z < 10. Such an agreement\nis useful since analytical models are better suited to quickly explore the full\nastrophysical and cosmological parameter space relevant for future 21-cm\nsurveys. We find, nevertheless, non-negligible differences that can be\nattributed to differences in the inhomogeneous X-ray heating and Lya coupling\nat z > 10 and, with upcoming interferometric data, these differences in return\ncan provide a way to better understand the astrophysical processes during\nreionization.","url_abs":"http://arxiv.org/abs/0708.2424v2","url_pdf":"http://arxiv.org/pdf/0708.2424v2.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":"abstracts"},"code_links":[{"paper_slug":"cosmic-reionization-and-the-21-cm-signal","repo_url":"https://github.com/mariogrs/Simfast21","is_official":0,"mentioned_in_paper":0,"mentioned_in_github":1,"framework":"none","reach":{"status":"ok"}}],"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}