{
  "bibcode": "2021GCN.30956....1K",
  "body": "A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin\non behalf of the MGNS/BepiColombo and HEND/Mars Odyssey teams,\n\nJ. Benkhoff on behalf of the BepiColombo team,\n\nK. Hurley, on behalf of the IPN,\n\nD. Svinkin, S. Golenetskii, D. Frederiks, A. Ridnaia,\nA. Lysenko, and T. Cline on behalf of the Konus-Wind team,\n\nA. Goldstein, M. S. Briggs, and C. Wilson-Hodge\non behalf of the Fermi GBM team,\n\nA. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,\nand C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,\n\nS. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu\non behalf of the Swift-BAT team, and\n\nW. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr,\non behalf of the GRS-Odyssey GRB team, report:\n\nThe long-duration GRB 210927B (GECAM-B detection: GCN circ. 30910)\nwas detected by BepiColombo (MGNS), in the vicinity of Mercury\n(see introductory GCN Circ. 30949); Mars-Odyssey (HEND);\nGECAM-B; Fermi (GBM trigger 654479691); Konus-Wind; INTEGRAL (SPI-ACS);\nand Swift (BAT) at about 86086 s UT (23:54:46).\nThe burst was outside the coded field of view of the BAT.\n\nThe burst light curves in the energy range 30 keV-1.5 MeV (HEND)\nand 250-450 keV (MGNS) exhibit a multi-peaked pulse structure\nwith a total duration of ~25 s.\n\nWe have triangulated GRB 210927B to the following 3 sigma annuli:\n---------------------------------------------------------\n          R.A.(J2000)  Dec.(J2000)    R      +dR     -dR\n                deg      deg         deg     deg     deg\n---------------------------------------------------------\nMGNS-HEND     2.101    -1.674      94.136  +0.034 -0.079\nKonus-HEND  187.856    -2.595      88.396  +0.017 -0.017\nKonus-GBM   161.442     7.403      85.952  +0.562 -0.562\n---------------------------------------------------------\n\nThe MGNS-HEND and Konus-HEND annuli intersect to form two error\nboxes one of which is inconsistent with the Konus-GBM annulus,\nthe KW ecliptic latitude response, and the Fermi (GBM) final position.\n\nThe correct preliminary, 3 sigma error box is:\n  ---------------------------------------------\n   RA(2000), deg                 Dec(2000), deg\n  ---------------------------------------------\n  Center:\n   263.021 (17h 32m 05s) +73.775 (+73d 46' 32\")\n  Corners:\n   263.554 (17h 34m 13s) +73.267 (+73d 15' 59\")\n   262.667 (17h 30m 40s) +74.201 (+74d 12' 03\")\n   262.825 (17h 31m 18s) +73.913 (+73d 54' 45\")\n   263.687 (17h 34m 45s) +72.979 (+72d 58' 46\")\n  ---------------------------------------------\nThe error box area is 49 sq. arcmin, and its maximum\ndimension is 1.26 deg (the minimum one is 2.0 arcmin).\nThe Sun distance was 89 deg.\n\nThis box may be improved.\n\nA triangulation map is posted at:\nhttp://l503.iki.rssi.ru/owncloud/index.php/s/nFbsu69DWdxQvd2",
  "circularId": 30956,
  "createdOn": 1634935740000,
  "email": "svinkin@mail.ioffe.ru",
  "subject": "IPN Triangulation of GRB 210927B",
  "submitter": "Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>",
  "eventId": "GRB 210927B"
}