TITLE: GCN CIRCULAR NUMBER: 16116 SUBJECT: IPN Triangulation of GRB 140416A (long/very intense) DATE: 14/04/18 14:35:36 GMT FROM: Dmitry Svinkin at Ioffe Institute K. Hurley and J. Goldsten, on behalf of the MESSENGER NS GRB team, S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, V. Connaughton, M. S. Briggs, C. Meegan, V. Pelassa, and A. Goldstein, on behalf of the Fermi GBM team, I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin, on behalf of the HEND-Odyssey GRB team, and G. Di Cocco, F. Fuschino, M. Galli, C. Labanti, and M. Marisaldi, on behalf of the AGILE MCAL team, report: The long-duration very intense GRB 140416A (P. Jenke, GCN Circ. 16115) has been observed by Fermi (GBM: trigger 419304403), Konus-Wind, AGILE (MCAL), MESSENGER (GRNS), and Mars-Odyssey (HEND), so far, at about 5201 s UT (01:26:41). These annuli intersect to form a long arc, whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 40.186 (02h 40m 45s) +39.527 (+39d 31' 37") Corners: 25.842 (01h 43m 22s) +45.226 (+45d 13' 35") 27.972 (01h 51m 53s) +44.893 (+44d 53' 35") 50.081 (03h 20m 20s) +30.017 (+30d 01' 02") 50.783 (03h 23m 08s) +28.603 (+28d 36' 11") --------------------------------------------- The error box area is 2.023 sq. deg, and its maximum dimension is 25.8 deg (the minimum one is 0.164 deg). This error box may be improved. Because the Earth, the Wind, the Mars-Odyssey, and the MESSENGER satellites are nearly aligned at the moment (the angular distance between Wind and MESSENGER is 10.3 deg and between Wind and Mars-Odyssey is 170 deg), the annuli intersect at grazing incidence and the resulting 3-sigma box is long. The center of the GBM ground position given in P. Jenke, GCN Circ. 16115 (that is RA, Dec, RErr = 35.4, 43.9, 1.0 deg) is 5.4 deg from the box center and is 1.5 deg from the center line of the Konus-MESSENGER annulus. A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB140416_T05196/IPN/