IPN triangulation of GRB 210204A

The long-duration GRB 210204A (Fermi-GBM detection: The Fermi GBM team, GCN Circ. 29390; Bissaldi, GCN Circ. 29393; BALROG localization: Kunzweileret al., GCN Circ. 29391; GECAM detection: Li, GCN Circ. 29392) has been detected by Fermi (GBM trigger 634112970), INTEGRAL (SPI-ACS), Konus-Wind, Mars-Odyssey (HEND), and Swift (BAT), so far, at about 23365 s UT (06:29:25). The burst was outside the coded field of view of the BAT. We have triangulated it to a preliminary, error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 118.116 (07h 52m 28s) +15.249 (+15d 14' 57") Corners: 120.374 (08h 01m 30s) +23.758 (+23d 45' 30") 115.277 (07h 41m 07s) +4.395 ( +4d 23' 43") 114.946 (07h 39m 47s) +4.455 ( +4d 27' 16") 120.017 (08h 00m 04s) +23.825 (+23d 49' 30") --------------------------------------------- The error box area is 6.7 sq. deg, and its maximum dimension is 20.0 deg (the minimum one is 20 arcmin). The Sun distance was 155 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. 29390 and 29391). The optical transient ZTF21aagwbjr/AT2021buv (Kool et al., GCN Circ. 29405) is inside the box, lending support to the association of the transient and the burst. A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB210204_T23570/IPN/ The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular.