TITLE: GCN CIRCULAR NUMBER: 16327 SUBJECT: IPN Triangulation of GRB 140523A DATE: 14/05/24 15:50:16 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks, D. Svinkin, and T. Cline, on behalf of the Konus-Wind team, K. Hurley and J. Goldsten, on behalf of the MESSENGER NS GRB team, V. Connaughton, M. S. Briggs, C. Meegan, V. Pelassa, and A. Goldstein, on behalf of the Fermi GBM team, A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, and S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer, on behalf of the Swift-BAT team, report: The long-duration, bright GRB 140523A (von Kienlin and Connaughton, GCN Circ. 16321) has been observed by Fermi (GBM), Konus-Wind, INTEGRAL (SPI-ACS), Swift (BAT) and MESSENGER (GRNS), so far, at about 11157 s UT (03:05:57). The burst was outside the coded field of view of the BAT. We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: ------------------------------------------------ RA(2000), deg Dec(2000), deg ------------------------------------------------ Corners: 1: 133.480 (08h 53m 55s) +25.815 (+25d 48' 56") 2: 133.425 (08h 53m 42s) +25.820 (+25d 49' 11") 3: 132.929 (08h 51m 43s) +24.467 (+24d 28' 02") 4: 132.267 (08h 49m 04s) +21.927 (+21d 55' 36") 5: 132.459 (08h 49m 50s) +21.913 (+21d 54' 46") 6: 132.669 (08h 50m 41s) +22.509 (+22d 30' 32") ----------------------------------------------- The error box area is ~0.7 sq.deg, and its maximum dimension is 4.0 deg (the minimum one is 12 arcmin). This box can be improved. The box partially overlaps the LAT error circle (Vianello, Racusin, and Arimoto, GCN Circ. 16322). The possible X-ray afterglow candidate (D'Elia and Izzo, GCN Circ. 16324) is marginally consistent with the box. A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB140523_T11157/IPN/ Details of the Konus-Wind observation will be given in a forthcoming GCN Circular.