{"paper":{"title":"A hot cocoon in the ultralong GRB 130925A: hints of a PopIII-like progenitor in a low density wind environment","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.HE","authors_text":"Bruce Gendre, Eleonora Troja, Fabrizio Fiore, Gabriele Ghisellini, Keith Bannister, Lauren A. Kidd, Luigi Piro, Mark H. Wieringa, Roberto Ricci, Silvia Piranomonte","submitted_at":"2014-05-12T19:59:56Z","abstract_excerpt":"GRB 130925A is a peculiar event characterized by an extremely long gamma-ray duration ($\\approx$7 ks), as well as dramatic flaring in the X-rays for $\\approx$20 ks. After this period, its X-ray afterglow shows an atypical soft spectrum with photon index $\\Gamma$$\\sim$4, as observed by Swift and Chandra, until $\\approx 10^7$ s, when XMM-Newton observations uncover a harder spectral shape with $\\Gamma$$\\sim$2.5, commonly observed in GRB afterglows. We find that two distinct emission components are needed to explain the X-ray observations: a thermal component, which dominates the X-ray emission f"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1405.2897","kind":"arxiv","version":3},"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"}