TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2646 SUBJECT: IPN/HETE localizations of GRB040810 (=H3489) DATE: 04/08/17 00:02:11 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses, HETE, Mars Odyssey, and Konus GRB teams, I. Mitrofanov, S. Charyshnikov, V. Grinkov, A. Kozyrev, M. Litvak, and A. Sanin, on behalf of the HEND-Odyssey GRB team, W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr, on behalf of the GRS-Odyssey GRB team, E. Mazets and S. Golenetskii, on behalf of the Konus-Wind GRB team, G. Ricker, J-L Atteia, N. Kawai, D. Lamb, S. Woosley, J. Doty, R. Vanderspek, J. Villasenor, G. Crew, N. Butler, J.G. Jernigan, F. Martel, G. Prigozhin, A. Dullighan, J. Braga, R. Manchanda, G. Pizzichini, Y. Shirasaki, C. Graziani, M. Matsuoka, T. Tamagawa, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi, T. Donaghy, C. Barraud, M. Boer, J-F Olive, and J-P Dezalay, on behalf of the HETE GRB team, D. M. Smith, R. P. Lin, J. McTiernan, R. Schwartz, C. Wigger, W. Hajdas, and A. Zehnder, on behalf of the RHESSI GRB team, report: Mars Odyssey (HEND), Konus-Wind, HETE (FREGATE and WXM), and RHESSI observed this burst. Ulysses was off. HETE Ground Analysis produced two error circles for it, distributed as GCN Notices Sequence 3 and 4. The burst occurred after HETE sunrise, at orbital phase=0.78, just as the science instruments were being shut off; as a result, HETE observed only the precursor to this long, intense event (GCN 2641, Aptekar et al.). The HETE star trackers were also off at the time of the burst, so spacecraft aspect could only be established crudely using the spacecraft sun sensors. We have triangulated this burst to two annuli, whose coordinates are RA, Decl = 332.624, -12.452 degrees, with radius 34.105 +/-0.014 degrees, and RA, Decl = 309.285, -21.748 degrees, with radius 46.199 +/- 1.815 degrees (3 sigma values). These annuli intersect to form an error box whose area is ~780 sq. arcmin., and whose corners are given by: RA Decl. 2.438 -33.023 357.554 -38.402 2.438 -32.967 357.562 -38.353 The larger of the two IPN annuli encompasses parts of both HETE WXM error circles. The smaller annulus, however, intersects the larger WXM error circle in Sequence Number 3, but not the smaller one given in Sequence Number 4. The intersection forms an error box whose area is ~90 sq. arcmin., and whose corners are given by: RA Decl. 359.134 -36.959 359.716 -36.366 359.002 -37.043 359.788 -36.244 A map has been posted at ssl.berkeley.edu/ipn3/040810.