TITLE: GCN CIRCULAR NUMBER: 40127 SUBJECT: IPN triangulation of GRB 250407A DATE: 25/04/09 07:14:45 GMT FROM: Dmitry Svinkin at Ioffe Institute svinkin@mail.ioffe.ru
A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin on behalf of the MGNS/BepiColombo team,
D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia, and T. Cline on behalf of the Konus-Wind team,
A. Goldstein, M. S. Briggs, C. Wilson-Hodge, and E. Burns on behalf of the Fermi GBM team, report:
The very bright, long-duration GRB 250407A (Fermi-GBM detection: The Fermi GBM team, GCN 40104; Mukherjee and Meegan, GCN 40114; BALROG localization: Preis et al., GCN 40105; SVOM-GRM detection: Wang et al., GCN 40120; Konus-Wind detection: Ferderiks et al., GCN 40121) was detected by Fermi (GBM trigger 765733706), Konus-Wind, and BepiColombo (MGNS) at about 56901 s UT (15:48:21).
We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 110.410 (07h 21m 38s) +35.618 (+35d 37' 06") Corners: 111.023 (07h 24m 05s) +37.563 (+37d 33' 48") 111.028 (07h 24m 07s) +37.670 (+37d 40' 12") 109.794 (07h 19m 10s) +33.403 (+33d 24' 09") 109.787 (07h 19m 09s) +33.265 (+33d 15' 53") --------------------------------------------- The error box area is 364 sq. arcmin, and its maximum dimension is 4.52 deg (the minimum one is 1.4 arcmin). The Sun distance was 89 deg.
This localization may be improved.
The IPN localization is consistent with, but reduces the area of, the Fermi-GBM final (GCN 40104) and BALROG (GCN 40105) localizations.
The X-ray transient detected by SRG-ART-XC (GCN 40110) and Swift-XRT (GCN 40113) is inside the box, which further strengthen the interpretation of the transient as the burst afterglow.
A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB250407_T56895/IPN
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