TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2665 SUBJECT: Increase of SGR 1806-20 activity DATE: 04/08/26 15:19:46 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks on behalf of Konus-Wind and Helicon/Coronas-F teams, T. Cline on behalf of the Konus-Wind team, and A. Rau, A. von Kienlin, G. Lichti on behalf of the INTEGRAL SPI-ACS GRB team report: Recently the increase of bursting activity from SGR 1806-20 was detected by Konus-Wind, INTEGRAL SPI-ACS, and Helicon-Coronas-F. Konus-Wind has detected 7 bursts in the trigger mode and 5 bursts in the background mode. Additional SGR-like burst was detected by Helicon-Coronas-F in the background mode and triggered INTEGRAL SPI-ACS (the burst was missed by Konus-Wind due to data read out). The most recent burst detected on August 25 at 85512.611 s UT is the brightest burst ever observed by Konus-Wind from SGR 1806-20. The following table summarizes the bursts: Date Time*, Duration, Fluence, Peak Flux, Observed by** s UT s (20-200 keV) (20-200 keV) ergs/cm2 ergs/cm2 s ----------------------------------------------------------------------- 040814 45466.575 0.18 1.6E-6 2.1E-5 K(tr) 040819 22636.891 0.80 1.4E-5 2.5E-5 K(tr) 040820 71208.277 0.06 9.4E-7 3.1E-5 K(tr) 040821 35217 <3 1.7E-6 - K(bg), I 040821 61297.013 0.22 2.5E-6 2.0E-5 K(tr), I 040822 9646 <3 5.0E-7 - K(bg) 040823 22462 <3 8.0E-7 - K(bg) 040823 36755 <3 5.0E-7 - K(bg) 040823 40994.643 0.14 1.5E-6 4.5E-5 K(tr) 040823 48073.891 0.70 1.0E-5 4.2E-5 K(tr), I, H(bg) 040823 48363 <2 3.2E-6 - I, H(bg) 040823 58681 <3 6.0E-7 - K(bg) 040825 85512.611 1.10 2.1E-5 7.0E-5 K(tr), I ------------------------------------------------------------------------ * - Konus-Wind (or Helicon) time is given ** - the last column contains the s/c which observed this burst: K - Konus-Wind, I - INTEGRAL SPI-ACS, H - Helicon-Coronas-F. For Konus and Helicon in the brackets the observation mode is given: tr - trigger, bg - background. The Konus-INTEGRAL annuli for 3 bursts are: Date Time, Center Radius s UT RA DEC and its uncertainty (3sigma) deg deg deg ---------------------------------------------------- 040821 61297.013 310.141 -16.864 35.724+/-0.678 040823 48073.891 311.668 -14.712 37.647+/-0.762 040825 85512.611 314.503 -14.941 40.588+/-0.454 Because all these annuli pass through the position of SGR 1806-20, we believe that it is the source of these events. The Konus ecliptic latitude response indicates that the source of the remaining bursts (except the missed one) is near ecliptic plane, so we suppose, that they are also originated from SGR 1806-20.