{"paper":{"title":"Long Term Variability of Cygnus X-1. IV. Spectral Evolution 1999-2004","license":"","headline":"","cross_cats":[],"primary_cat":"astro-ph","authors_text":"(2) MIT-CXC, (3) CASS-UCSD, (4) MRAO Cambridge, (5) IAA Tuebingen), G. G. Pooley (4), J. Wilms (1), K. Pottschmidt (3), M. A. Nowak (2), S. Fritz (5) ((1) Warwick","submitted_at":"2005-10-06T19:51:17Z","abstract_excerpt":"(abbreviated abstract) We present the long term spectral evolution of the Galactic black hole candidate Cygnus X-1 in the X-rays and at 15GHz using ~200 pointed observations taken between early 1999 and late 2004 with RXTE and the Ryle radio telescope. The X-ray spectra are remarkably well described by a simple broken power law spectrum with an exponential cutoff. Physically motivated Comptonization models, e.g., compTT or eqpair, can reproduce this simplicity. Broken power law models reveal a significant linear correlation between the photon index of the lower energy power law and the hardeni"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"astro-ph/0510193","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/astro-ph/0510193/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"}