TITLE: GCN CIRCULAR NUMBER: 41940 SUBJECT: IPN triangulation of GRB 250920A (long/bright) DATE: 25/09/22 16:39:14 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 HEND/Mars Odyssey 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, and W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr, and A.S. Gardner on on behalf of the GRS-Odyssey GRB team, report: The bright, long-duration GRB 250920A (Ferm-GBM detection: The Fermi GBM team, GCN 41895; Sonawane and Smith, GCN 41918; BALROG localization: Preis and Greiner, GCN 41896 AstroSat-CZTI detection: Harsha et al., GCN 41899; SVOM-GRM detection: Wang et al., GCN 41912; NuSTAR-detection: Waratkar et al., GCN 41926) was detected by Fermi (GBM trigger 780029651), SVOM (GRM), AstroSat (CZTI), NuSTAR, Konus-Wind, and Mars-Odyssey (HEND), at about 10447 s UT (02:54:07). We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 176.909 (11h 47m 38s) +54.466 (+54d 27' 56") Corners: 177.868 (11h 51m 28s) +54.769 (+54d 46' 07") 177.751 (11h 51m 00s) +54.775 (+54d 46' 28") 175.963 (11h 43m 51s) +54.152 (+54d 09' 06") 176.079 (11h 44m 19s) +54.148 (+54d 08' 54") --------------------------------------------- The error box area is 168 sq. arcmin, and its maximum dimension is 1.27 deg (the minimum one is 2.3 arcmin). The Sun distance was 53 deg. This localization may be improved. A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB250920_T10444/IPN/ The HEALPix triangulation map is the multi-order HEALPix in units of probability density. The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular. View this GCN Circular online at https://gcn.nasa.gov/circulars/41940. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...