{"paper":{"title":"Can the 21 cm signal probe Population III and II star formation?","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.GA"],"primary_cat":"astro-ph.CO","authors_text":"Hidenobu Yajima, Sadegh Khochfar (University of Edinburgh)","submitted_at":"2014-05-28T20:06:50Z","abstract_excerpt":"Using varying models for the star formation rate (SFR) of Population (Pop) III and II stars at z>6 we derive the expected redshift history of the global 21 cm signal from the inter-galactic medium (IGM). To recover the observed Thomson scattering optical depth of the cosmic microwave background (CMB) requires SFRs at the level of ~ 10^-3 Msun/yr/Mpc^3 at z ~ 15 from Pop III stars, or ~ 10^-1Msun/yr/Mpc^3 at z ~ 7 from Pop II stars. In the case the SFR is dominated by Pop III stars, the IGM quickly heats above the CMB at z > 12 due to heating from supernovae. In addition, Lyman-alpha photons fr"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1405.7385","kind":"arxiv","version":2},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}