TITLE: GCN GRB OBSERVATION REPORT NUMBER: 861 SUBJECT: ASM Localization of GRB 001025 DATE: 00/10/25 21:19:27 GMT FROM: Don Smith at MIT D. A. Smith (UMich), A. M. Levine, and R. Remillard (MIT), on behalf of the RXTE/ASM teams at MIT and NASA/GSFC, and and K. Hurley (UCB) and T. Cline (NASA/GSFC) on behalf of the NEAR GRB team, report: The RXTE All-Sky Monitor has detected a gamma-ray burst, beginning at about 03:10:05 UTC on 25 Oct 2000. As recorded by the ASM, the light curve consists of a single peak, lasting approximately 15-20 seconds. The event was hard, as measured in the ASM, reaching a peak 5-12 keV flux of ~4 Crab, and a 1.5-3 keV flux of ~1.5 Crab. It was detected in a single camera, yielding an error box with a length of 1.6 degrees and a width of 4.0 arcminutes. The center of the error box is at R.A. = 8h38m, Decl. = -13o16'.0 (J2000.0). The corners of the box are at the locations: 130.2309d {08h40m55s} -13.6681d {-13o40'05"} 130.2542d {08h41m01s} -13.6247d {-13o37'29"} 128.7598d {08h35m02s} -12.8590d {-12o51'32"} 128.7357d {08h34m57s} -12.9034d {-12o54'12"} NEAR also observed this burst. As observed by NEAR, in the energy range >~100 keV, and with 1 s resolution, the burst consisted of a single one second long spike followed by weak emission for ~5 seconds. A very coarse comparison of the NEAR and RXTE times gives an annulus which contains, but does not improve upon the ASM error box. Data from the Konus-Wind and/or Ulysses experiments will be available around 0600 UT on the 26th, and should result in a small RXTE/IPN error box. See the web page at http://xte.mit.edu/grb001025/ for figures and further developments.