Title: Target of Opportunity Observation of a Major Radio/Hard X-Ray Flare in the Relativistic Jet Source Cygnus X-3


Proposal ID: 0120171
Subject category: Compact Object
Principal investigator: McCollough
Institute: NSSTC/NASA


Abstract

We propose a Target of Opportunity Observation (TOO) of a major radio/hard X-ray flare of the realtivistic jet source Cyg X-3. These observations will provide an opportunity to use INTEGRAL's unique capabilities to explore the hard X-ray/Gamma-ray emission which occurs during jet production in this system. We present in this proposal evidence for the production of highly relativistic jets that have corresponding hard X-ray/Gamma-ray emission. The proposed observation will allow us to examine the nature of this emission and possibly detect the presence of annihilation lines. Additional, if lines are detected and have Doppler shifts, we can directly measure the speed of the jets. The detection of any annihilation feature associated with these jets would allow us an important step towards solving the problem of what jets are made of. Unlike the core program TOOs for Cyg X-3, these observations will be triggered strictly based on radio monitoring observations. The core program TOOs are based on the high hard X-ray fluxes (above 400 mCrab) and very low hard X-ray fluxes (less than 10 mCrab). From our study of the BATSE and the radio data we know that the former condition is likely to occur only during radio quiescence and the later occurs during periods preceding major radio flares (by as much as 30 days or more). The best method of determining the time of a major radio flare is by extensive monitoring in the radio (daily) by several observatories around the world. This is the basis for our triggering criteria. Also from a study of the BATSE data one should not expect the peak of the hard X-ray flare associated with the jet to be no greater than about 125 mCrab in the 20-100 keV bandpass.