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.