{"paper":{"title":"Project AMIGA: A Minimal Covering Factor for Optically Thick Circumgalactic Gas Around the Andromeda Galaxy","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"Andrew J. Fox, Bart P. Wakker, Christopher B. Wotta, Claude-Andre Faucher-Giguere, D.J. Pisano, Edward B. Jenkins, Felix J. Lockman, Jason Kalirai, Jay Strader, J. Christopher Howk, John M. O'Meara, Joseph Ribaudo, J. Xavier Prochaska, Kathleen A. Barger, Kyle R. Stewart, Lauren Corlies, Michelle A. Berg, Molly S. Peeples, Nicolas Lehner, Puragra Guhathakurta, Spencer A. Wolfe, Zachary Hafen","submitted_at":"2017-06-06T18:00:05Z","abstract_excerpt":"We present a deep search for HI 21-cm emission from the gaseous halo of Messier 31 as part of Project AMIGA, a large program Hubble Space Telescope program to study the circumgalactic medium of the Andromeda galaxy. Our observations with the Robert C. Byrd Green Bank Telesope target sight lines to 48 background AGNs, more than half of which have been observed in the ultraviolet with the Cosmic Origins Spectrograph, with impact parameters $25 \\lesssim \\rho \\lesssim 330$ kpc ($0.1 \\lesssim \\rho / R_{\\rm vir} \\lesssim 1.1$). We do not detect any 21-cm emission toward these AGNs to limits of $N({\\"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1706.01893","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"}