{
  "circularId": 41875,
  "eventId": "GRB 250919A",
  "subject": "Fermi GRB 250919A: Global MASTER-Net observations report",
  "bibcode": "2025GCN.41875....1L",
  "body": "V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, \nG.Antipov,  A.Sankovich, Yu.Tselik, Ya.Kechin, V.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.Sosnovskij (CrAO),\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 250919A ( Fermi GBM team, GCN 41874) errorbox  557 sec after notice time and 592 sec after trigger time at 2025-09-19 00:38:44 UT, with upper limit up to  19.3 mag. The observations began at zenith distance = 63 deg. The sun  altitude  is -47.5 deg. \n\nMASTER-OAFA robotic telescope  located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 250919A errorbox  658 sec after notice time and 693 sec after trigger time at 2025-09-19 00:40:26 UT, with upper limit up to  20.3 mag. The observations began at zenith distance = 19 deg. The sun  altitude  is -28.7 deg. \n\nThe galactic latitude b = -34 deg., longitude l = 350 deg.\n\n\nReal time updated cover map and OT discovered available here: \nhttps://master.sai.msu.ru/site/master2/observ.php?id=2994728\n\nWe obtain a following upper limits.  \n\nTmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment\n_________|_____________________|_____________________|____________________________________|_____|_______|_______|________\n\n     622 | 2025-09-19 00:38:44 |         MASTER-SAAO | (20h 12m 52.30s , -49d 54m 57.2s) |   C |    60 | 19.3 |        \n     622 | 2025-09-19 00:38:44 |         MASTER-SAAO | (20h 10m 02.82s , -49d 39m 38.7s) |   C |    60 | 19.2 |        \n     764 | 2025-09-19 00:40:26 |         MASTER-OAFA | (20h 13m 10.49s , -49d 55m 27.8s) |   C |   140 | 20.2 |        \n     925 | 2025-09-19 00:42:52 |         MASTER-OAFA | (20h 13m 10.79s , -49d 55m 23.7s) |   C |   170 | 20.3 |        \nFilter C is a clear (unfiltred) band. \n\n\nThe observation and reduction will continue. \nThe message may be cited.\n",
  "createdOn": 1758245459562,
  "submitter": "Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>",
  "submittedHow": "email"
}