{"paper":{"title":"The Surface Mass Density and Structure of the Outer Disk of NGC 628","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.CO","authors_text":"Daniel Christlein, Dennis Zaritsky, Sheila J. Kannappan, St\\'ephane Herbert-Fort","submitted_at":"2010-03-23T21:22:07Z","abstract_excerpt":"We study the kinematics of GALEX-selected H_alpha knots in the outer disk (beyond R25) of NGC 628 (M74), a galaxy representative of large, undisturbed, extended UV (Type 1 XUV) disks.  Our spectroscopic target sample of 235 of the bluest UV knots surrounding NGC 628 yielded 15 H_alpha detections (6%), roughly the number expected given the different mean ages of the two populations.  The measured vertical velocity dispersion of the H_alpha knots between 1 - 1.8 R25 (13.5 - 23.2 kpc) is < 11 km/s.  We assume that the H_alpha knots trace an 'intermediate' vertical mass density distribution (betwe"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1003.4536","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"}