Fermi GRB 250107B: Global MASTER-Net observations report

MASTER-Tunka robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB 250107B ( Fermi GBM team, GCN 38839) errorbox 14186 sec after notice time and 14221 sec after trigger time at 2025-01-07 15:31:05 UT, with upper limit up to 19.3 mag. The observations began at zenith distance = 12 deg. The sun altitude is -55.2 deg. The galactic latitude b = 28 deg., longitude l = 157 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2736509 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 14251 | 2025-01-07 15:31:05 | MASTER-Tunka | (04h 13m 49.68s , +54d 32m 00.7s) | C | 60 | 19.1 | 14311 | 2025-01-07 15:31:05 | MASTER-Tunka | (04h 13m 49.68s , +54d 32m 00.8s) | C | 180 | 19.1 | Coadd 14483 | 2025-01-07 15:34:57 | MASTER-Tunka | (04h 27m 33.78s , +54d 31m 30.6s) | C | 60 | 19.3 | 14543 | 2025-01-07 15:34:57 | MASTER-Tunka | (04h 27m 33.77s , +54d 31m 30.6s) | C | 180 | 19.3 | Coadd 14557 | 2025-01-07 15:36:11 | MASTER-Tunka | (03h 58m 53.28s , +56d 25m 31.5s) | C | 60 | 18.8 | 14617 | 2025-01-07 15:36:11 | MASTER-Tunka | (03h 58m 53.29s , +56d 25m 31.6s) | C | 180 | 18.8 | Coadd 14719 | 2025-01-07 15:38:53 | MASTER-Tunka | (04h 13m 21.56s , +56d 24m 57.2s) | C | 60 | 19.0 | 14953 | 2025-01-07 15:42:46 | MASTER-Tunka | (04h 13m 49.60s , +54d 32m 46.9s) | C | 60 | 19.0 | 15109 | 2025-01-07 15:45:23 | MASTER-Tunka | (04h 27m 30.11s , +54d 32m 56.0s) | C | 60 | 19.1 | 15183 | 2025-01-07 15:46:37 | MASTER-Tunka | (03h 58m 51.42s , +56d 25m 51.6s) | C | 60 | 18.6 | 15803 | 2025-01-07 15:56:57 | MASTER-Tunka | (04h 13m 16.36s , +56d 26m 13.9s) | C | 60 | 17.8 | 16036 | 2025-01-07 16:00:50 | MASTER-Tunka | (04h 13m 42.42s , +54d 32m 55.6s) | C | 60 | 17.5 | 16206 | 2025-01-07 16:03:40 | MASTER-Tunka | (04h 27m 32.57s , +54d 33m 24.4s) | C | 60 | 17.0 | 16282 | 2025-01-07 16:04:56 | MASTER-Tunka | (03h 58m 39.55s , +56d 26m 20.1s) | C | 60 | 16.6 | 16530 | 2025-01-07 16:09:04 | MASTER-Tunka | (04h 13m 12.79s , +56d 26m 02.5s) | C | 60 | 17.4 | 16874 | 2025-01-07 16:14:47 | MASTER-Tunka | (04h 15m 44.55s , +52d 38m 47.2s) | C | 60 | 17.8 | 17283 | 2025-01-07 16:21:36 | MASTER-Tunka | (04h 01m 08.58s , +54d 33m 43.0s) | C | 60 | 18.4 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.