{"paper":{"title":"Where is OH and Does It Trace the Dark Molecular Gas (DMG)?","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"Carl Heiles, Claire E. Murray, Di Li, Duo Xu, Hiep Nguyen, John Dickey, Jorge Pineda, J. R. Dawson, L. Bronfman, Ningyu Tang, N. M. McClure-Griffiths, Paul F. Goldsmith, Sne\\v{z}ana Stanimirovi\\'c, Steven J. Gibson, the PRIMO collaboration, Thomas Troland, Tim Robishaw, Zhichen Pan","submitted_at":"2018-01-13T03:34:34Z","abstract_excerpt":"Hydroxyl (OH) is expected to be abundant in diffuse interstellar molecular gas as it forms along with $H_2$ under similar conditions and within a similar extinction range. We have analyzed absorption measurements of OH at 1665 MHz and 1667 MHz toward 44 extragalactic continuum sources, together with the J=1-0 transitions of $^{12}$CO, $^{13}$CO , and C$^{18}$O, and the J=2-1 of $^{12}$CO. The excitation temperature of OH were found to follow a modified log-normal distribution, $ f(T{\\rm_{ex}}) \\propto \\frac{1}{ \\sqrt{2\\pi}\\sigma } \\rm{exp}\\left[-\\frac{[ln(\\textit{T}_{ex})-ln(3.4\\ K)]^2}{2\\sigm"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1801.04373","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"}