|The INTEGRAL error circle of GRB040403
imaged April 3, 2004 20:05-23:50 UT through Rc filter.
Copyright: Nyrölä Observatory, 2004
TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2563 SUBJECT: GRB 040403: Optical observations DATE: 04/04/04 22:59:39 GMT FROM: Arto Oksanen at Nyrola Obs., Finland
P. Tikkanen and A. Oksanen on behalf of Nyrola observatory GRB Team and AAVSO International High Energy Network report: A 24 x 16 arcmin field covering the INTEGRAL error circle of GRB 040403 (GCN 2560) was imaged with the 0.4m SCT of the Nyrola Observatory starting at April 3, 2004 20:05 UT, 15.0 hours after the burst. Observation was taken under quite poor conditions, bright moonlight, northern lights and moderate seeing. Total of 53 four minute Rc-exposures, exposure time of 12720 seconds, were sigma reject combined and compared against the Digitized Sky Survey (DSS2R). No new objects brighter than DSS2 plate limit was detected, but some fainter objects were also present inside error circle. The faintest stars on the combined image are about Rc=20.4 (USNOA2.0 reference). The combined image is available on web: http://nyrola.jklsirius.fi/grb/grb040403 Nyrola observatory wants to express gratitude to AAVSO for loaning the CCD camera and to Wihuri foundation for generous grants for the observatory. The AAVSO International High Energy network is grateful for a generous grant from the Curry Foundation and to NASA for the financial support for the High Energy Workshops for Amateur Astronomers.