{"paper":{"title":"Physical insights from the spectrum of the radio halo in MACS J0717.5+3745","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.CO"],"primary_cat":"astro-ph.GA","authors_text":"A. Bonafede, A. Botteon, A. Drabent, A. Ignesti, A. S. Rajpurohit, C. J.Riseley, D. Wittor, E. Bonnassieux, F. Vazza, G. Brunetti, G. Di Gennaro, H. J. A. R\\\"ottgering, K. Rajpurohit, M. Brienza, M. Br\\\"uggen, M. Hoeft, N. Locatelli, R. Cassano, R. J. van Weeren, T. W. Shimwell, W. R. Forman","submitted_at":"2020-12-28T17:29:08Z","abstract_excerpt":"We present new LOFAR observations of the massive merging galaxy cluster MACS J0717.5+3745. The cluster hosts the most powerful radio halo known to date. These new observations, in combination with published uGMRT (300$-$850 MHz) and VLA (1$-$6.5 GHz) data, reveal that the halo is more extended than previously thought, with a largest linear size of $\\sim2.2 \\rm Mpc$. The halo shows a steep spectrum ($\\alpha_{144\\,\\text{MHz}}^{1.5\\,\\text{GHz}}\\sim-1.4$) and a steepening ($\\alpha_{1.5 \\text{GHz}}^{5.5 \\text{GHz}}\\sim-1.9$) above 1.5 GHz. We find a strong scattering in spectral index maps on scale"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2012.14373","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2012.14373/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"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"}