TITLE: GCN CIRCULAR NUMBER: 29727 SUBJECT: IPN triangulation of GRB 210324C DATE: 21/03/25 18:28:37 GMT FROM: Anna Ridnaia at Ioffe Institute K. Hurley, on behalf of the IPN, I. G. Mitrofanov, D. V. Golovin, A. S. Kozyrev, M. L. Litvak, and A. B. Sanin, on behalf of the HEND-Odyssey GRB team, A. Ridnaia, S. Golenetskii, D. Frederiks, D. Svinkin, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, A. Goldstein, M. S. Briggs, and C. Wilson-Hodge 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 W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on behalf of the GRS-Odyssey GRB team, report: The long-duration GRB 210324C (Fermi-GBM detection: The Fermi GBM team, GCN Circ. 29718; BALROG localization: Kunzweileret et al., GCN Circ. 29719) has been detected by Fermi (GBM trigger 638308803), INTEGRAL (SPI-ACS), Konus-Wind, and Mars-Odyssey (HEND), so far, at about 71998 s UT (19:59:58). We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 35.111 (02h 20m 27s) -48.606 (-48d 36' 21") Corners: 43.843 (02h 55m 22s) -51.173 (-51d 10' 22") 43.444 (02h 53m 46s) -51.998 (-51d 59' 54") 27.400 (01h 49m 36s) -45.327 (-45d 19' 38") 27.969 (01h 51m 53s) -44.554 (-44d 33' 15") --------------------------------------------- The error box area is 10.7 sq. deg, and its maximum dimension is 12.7 deg (the minimum one is 51 arcmin). The Sun distance was 51 deg. This box may be improved. The IPN localization is consistent with, but reduces the area of, the Fermi RoboBA and BALROG localizations (GCN Circ. 29718 and 29719). A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB210324_T72000/IPN/ The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular.