1 National Space Institute, Technical University of Denmark2 Astrophysics, National Space Institute, Technical University of Denmark
The source detected by SWIFT (ATEL #853) was independently found in archived JEM-X public data in 5 pointings covering 18200s between 2004-07-19, 19:14 UTC and 2004-07-20, 03:27 UTC. Positioned within 1.2 degrees of Cyg X-3 it has been inside the JEM-X field-of-view more than 400 times with an off-axis angle less than 4 deg between 2002-12-16 and 2005-05-14. The search shows no firm detection except on the date mentioned above. The emission around 2004-07-19, 19:44 UTC can be fit by a powerlaw spectrum with a photon index of 2.0+-0.1 where the intensity reached 25 mCrab decreasing over the next 6 hours. (The source was observed only intermittently due to INTEGRAL dither pointings.) A search using OSA5.1 software in the ISGRI images from the same period in the 20 - 30 keV range showed no sign of the source. The source position was best determined in the 4 - 15 keV energy interval to be RA = 309.264 deg, DEC = 41.833 (J2000) with a 90% error radius of 1.1 arcmin.