Radio flare in Cygnus X-1
ATel #242; Guy Pooley (Cavendish Lab, Cambridge UK)
on 21 Feb 2004; 08:41 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: Guy Pooley (ggp1@cam.ac.uk)
Subjects: Radio, Infra-Red, Optical, X-ray, Request for Observations, Black Hole, Transient
A major and extremely unusual flare in the radio emission from Cygnus X-1 has been detected.
The observation at 15 GHz with the Ryle Telescope in Cambridge (UK) started on 2004 Feb 20
at UT 06h15m. The initial flux denstiy was 60 mJy, and rose to 140 mJy in < 30 min, followed
by a rapid decline. After about 2 h the flux density returned to its 'quiescent' range
of 10 - 15 mJy for the remaining 7 hours of observing.
A plot of the data, with nominal 32-second integrations, is available at http://www.mrao.cam.ac.uk/~guy/cx1/040220.ps
Cygnus X-1 radio flare
