Microquasars, Galactic binary systems showing extended and variable radio emission, are potential gamma-ray emitters. Indications of gamma-ray transient episodes have been reported in at least two systems, Cyg X-1 and Cyg X-3. The identification of additional gamma-ray emitting microquasars is key for a better understanding of these systems. Very-high-energy gamma-ray emission from microquasars has been predicted to happen during periods of transient outbursts potentially connected with the formation of a jet-like outflow. Contemporaneous observations using the H.E.S.S. telescope array and the RXTE satellite were obtained on three microquasars: GRS 1915+105, Circinus X-1 and V4641 Sgr with the aim of detecting a broadband flaring event in the very-high-energy gamma-ray and X-ray bands. We report here on the analysis of these data for each system, including a detailed X-ray analysis assessing the location of the sources in a hardness-intensity diagram during the observations. Finally we discuss the derived upper limits on their very-high-energy gamma-ray flux. The analyses presented here will soon be the subject of a detailed publication of the H.E.S.S. Collaboration .
|Original language||English (US)|
|Journal||Proceedings of Science|
|State||Published - 2015|
|Event||34th International Cosmic Ray Conference, ICRC 2015 - The Hague, Netherlands|
Duration: Jul 30 2015 → Aug 6 2015