2008/03/27 by A. Joinet, E. Kalemci, F. Senziani
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #Pulsars and Gravitational Waves Research #astro-ph
paper · pdf · doi:10.1086/533512
24 pages, 5 figures, accepted for publication in the Astrophsical Journal
arxiv created 2008/03/27 · openalex publication_date 2008/05/13 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We present an analysis of the high-energy emission of the Galactic black hole GRO J1655–40 at the beginning of its 2005 outburst. The data from 458 ks of INTEGRAL observations, spread over 4 weeks, are analyzed, along with the existing simultaneous RXTE and Swift data. The high-energy data allow us to detect the presence of a high-energy cutoff and to study its evolution during the outburst rise. This high-energy feature is generally related to thermal mechanisms in the framework of Comptonization models from which we can estimate the plasma parameters. We found an electron temperature of about 30-40 keV and an optical depth of around 1.8-2.1. The high-energy cutoff decreased along with the radio flux and disappeared as the jet turned off.