{"paper":{"title":"GRB 130925A: an ultra-long Gamma Ray Burst with a dust-echo afterglow, and implications for the origin of the ultra-long GRBs","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.HE","authors_text":"A.J. Castro-Tirado, A. Lien, A.P. Beardmore, B.-B. Zhang, D.D. Frederiks, D. G\\\"otz, D.N. Burrows, D.S. Svinkin, Hitoshi Negoro, J.A. Kennea, J. Cummings, J. Gorosabel, J.P. Osborne, Kazuhiko Suzuki, K. Wiersema, N. Gehrels, N.R. Tanvir, P.A. Evans, P.T. O'Brien, R.L.C. Starling, R. S\\'anchez-Ram\\'irez, R. Willingale, Satoshi Nakahira, S. Jeong, S. Xiong, V.D. Pal'shin, V. Savchenko","submitted_at":"2014-03-17T12:23:01Z","abstract_excerpt":"GRB 130925A was an unusual GRB, consisting of 3 distinct episodes of high-energy emission spanning $\\sim$20 ks, making it a member of the proposed category of `ultra-long' bursts. It was also unusual in that its late-time X-ray emission observed by Swift was very soft, and showed a strong hard-to-soft spectral evolution with time. This evolution, rarely seen in GRB afterglows, can be well modelled as the dust-scattered echo of the prompt emission, with stringent limits on the contribution from the normal afterglow (i.e. external shock) emission. We consider and reject the possibility that GRB "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1403.4079","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"}