{
  "circularId": 39694,
  "bibcode": "2025GCN.39694....1L",
  "eventId": "GRB 250312B",
  "submitter": "Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>",
  "submittedHow": "email",
  "createdOn": 1741817740643,
  "subject": "Fermi GRB 250312B: Global MASTER-Net observations report",
  "body": "V.Lipunov, E.Gorbovskoy, N.Tiurina,  P.Balanutsa, , D.Vlasenko, I.Panchenko,\nA.Kuznetsov,  G.Antipov,  A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin,\nV.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU),\nO.Gress, N.Budnev (ISU),\nC.Francile,  F. Podesta, R.Podesta, E. Gonzalez  (Observatorio Astronomico Felix Aguilar (OAFA),\nA. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),\nA. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)\nD.Buckley (SAAO),\nR.Rebolo (The Instituto de Astrofisica de Canarias),\nL.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,\nA.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) \n\nMASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 250312B ( Fermi GBM team, GCN 39692) errorbox  1617 sec after notice time and 1650 sec after trigger time at 2025-03-12 21:04:27 UT, with upper limit up to  18.4 mag. The observations began at zenith distance = 25 deg. The sun  altitude  is -47.1 deg. \n\nThe galactic latitude b = 11 deg., longitude l = 296 deg.\n\n\nReal time updated cover map and OT discovered available here: \nhttps://master.sai.msu.ru/site/master2/observ.php?id=2810182\n\nWe obtain a following upper limits.  \n\nTmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment\n_________|_____________________|_____________________|____________________________________|_____|_______|_______|________\n\n    1681 | 2025-03-12 21:04:27 |         MASTER-SAAO | (11h 29m 04.39s , -48d 18m 30.7s) |   C |    60 | 18.2 |        \n    3030 | 2025-03-12 21:26:57 |         MASTER-SAAO | (11h 29m 01.89s , -48d 17m 08.7s) |   C |    60 | 18.2 |        \n    3110 | 2025-03-12 21:28:16 |         MASTER-SAAO | (12h 02m 31.64s , -51d 04m 13.5s) |   C |    60 | 18.0 |        \n    3170 | 2025-03-12 21:28:16 |         MASTER-SAAO | (12h 02m 31.64s , -51d 04m 13.5s) |   C |   180 | 18.4 |  Coadd \n    3189 | 2025-03-12 21:29:35 |         MASTER-SAAO | (12h 02m 31.65s , -51d 04m 13.4s) |   C |    60 | 17.9 |        \n    3268 | 2025-03-12 21:30:54 |         MASTER-SAAO | (12h 02m 31.60s , -51d 04m 13.0s) |   C |    60 | 17.9 |        \n    3347 | 2025-03-12 21:32:13 |         MASTER-SAAO | (12h 02m 31.51s , -51d 04m 12.3s) |   C |    60 | 17.9 |        \nFilter C is a clear (unfiltred) band. \n\n\nThe observation and reduction will continue. \nThe message may be cited.\n"
}