Abstract
The ESA satellite COS-B viewed the Cyg-X region 7 times between November 1975 and March 1982. A search for periodic gamma-ray emission (E > 70 MeV) from Cyg X-3 at the characteristic ∼4.8 h period did not reveal the source. Combining all observations, the 2σ upperlimit (E > 70 MeV) on the flux for the phase interval in which X-ray emission has been detected is 1.0 × 10-6 ph cm-2 s-1 and for the phase intervals in which ultra-high-energy (E ≳ 500 GeV) gamma-ray emission has been reported ∼1.0 × 10-7 ph cm-2 s-1. This is about one and two orders of magnitude, repectively, below the flux reported earlier by the SAS-2 team. A comparison of the spatial gamma-ray distribution in the Cyg-X region measured by SAS-2 and COS-B with the total-interstellar-gas distribution leads to the conclusion that in both cases, COS-B and SAS-2, no source has been detected at the position of Cyg X-3 in addition to the diffuse gamma-ray emission expected from the total-gas distribution.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
