{"paper":{"title":"Fermi LAT and WMAP observations of the supernova remnant HB 21","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.HE","authors_text":"D.A. Smith, F. Acero, F. de Palma, F. Giordano, G.H. Janssen, G. Johannesson, G. Pivato, J. Ballet, J. Hewitt, L. Tibaldo, T.J. Brandt","submitted_at":"2013-11-02T17:02:58Z","abstract_excerpt":"We present the analysis of Fermi Large Area Telescope (LAT) $\\gamma$-ray observations of HB~21 (G89.0+4.7). We detect significant $\\gamma$-ray emission associated with the remnant: the flux >100 MeV is $9.4\\pm0.8(stat)\\pm1.6(syst)\\times10^{-11}$ erg cm$^{-2}$ s$^{-1}$. HB 21 is well modeled by a uniform disk centered at $l= 88{\\deg}.75\\pm 0{\\deg}.04$, $b = +4{\\deg}.65 \\pm 0{\\deg}.06$ with a radius of $1{\\deg}.19 \\pm 0{\\deg}.06$. The $\\gamma$-ray spectrum shows clear evidence of curvature, suggesting a cutoff or break in the underlying particle population at an energy of a few GeV. We complemen"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1311.0393","kind":"arxiv","version":1},"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"}