{"paper":{"title":"The Ultraluminous X-ray Source NGC 1313 X-2 (MS 0317.7-6647) and its Environment","license":"","headline":"","cross_cats":[],"primary_cat":"astro-ph","authors_text":"A. Treves, L. Zampieri, M. Chieregato, P. Kaaret, P. Mucciarelli, R. Di Stefano, R. Falomo, R. Turolla","submitted_at":"2003-10-26T22:01:05Z","abstract_excerpt":"We present new optical and {\\it Chandra} observations of the field containing the ultraluminous X-ray source NGC 1313 X-2. On an ESO 3.6 m image, the {\\it Chandra} error box embraces a $R=21.6$ point-like object and excludes a previously proposed optical counterpart. The resulting X-ray/optical flux ratio of NGC 1313 X-2 is $\\sim 500$. The value of $f_X/f_{opt}$, the X-ray variability history and the spectral distribution derived from a re-analysis of the {\\it ROSAT}, {\\it ASCA} and {\\it XMM} data indicate a luminous X-ray binary in NGC 1313 as a likely explanation for NGC 1313 X-2. If the X-r"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"astro-ph/0310739","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/astro-ph/0310739/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"}