{
  "bibcode": "2025GCN.41996....1P",
  "body": "\n\nR.Podesta, C.Francile,  F. Podesta, E. Gonzalez (OAFA, San Juan  Uni., Argentina);\n\nN.Tiurina, E.Gorbovskoy, V.Lipunov, A.Kuznetsov, A.Sankovich, G.Antipov, P.Balanutsa, Yu. Tselik, A. Sosnovskiy,  M.Shilova, A.Chasovnikov, V.Topolev,  K.Zhirkov, Ya.Kechin, V.Senik, D.Vlasenko(Lomonosov MSU, SAI, Moscow),\n\nD.Buckley, (SAAO, South Africa)\n\nO.Gress, N.Budnev (ISU, Irkutsk),\n\nA. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),\n\nA. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity),\n\nV.M.Pillet, R.Rebolo Lopez (The Instituto de Astrofisica de Canarias, Spain),\n\nL.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez,J.Martinez,A.R.Corella,\nL.H.Rodriguez (INAOE, Guillermo Haro  Astrophysic Observatory, Mexico)\n\nThe MASTER-OAFA robotic wide-field camera, located in Argentina (OAFA observatory of San Juan National University [1], during a regular survey, obtained an  image of the region of the sky containing the point with coordinates  MASTER OT J195412.89-485016.4 (GCN 41893) and source (Li et al., GCN 41877) before, during and after the Fermi trigger moment (GBM GCN 41874, GCN 41876, GCN 41890; LAT GCN 41884, Ttrigger=00:28:52) of GRB 250919A .\n\nVery bright optical counterpart MASTER OT J195412.89-485016.4\npromptly detected at the agnitude ~ 9 m.\n\nThis transient was first publishied as EP250919a optical counterpart by Las\nCumbres observatory (GCN 41877, t_detection=03:02:52.800 UTC)\nand as Fermi GRB 250919A/EP250919a optical counterpart by Gemini-South (LEvan et\nal. GCN 41883) with reshift detection z = 1.145\n\nX-ray counterpart was also detected by Swift (Osborne et al. GCN 41885) with OT afterglow detection by UVOT (Oates et\nal. GCN 41886), NuSTAR (GCN 41888) and Svom (41882).\n\nThe full 4 nights light curve is currently being processed.\n\n\n[1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023,  Astronomical Robotic Networks and\nOperative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp.\nhttp://www.pereplet.ru/lipunov/625.html#625\n",
  "subject": "GRB 250919A / EP250919a: Global MASTER Net before, during and after trigger optical observations",
  "submitter": "Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>",
  "createdOn": 1758869928334,
  "submittedHow": "email",
  "circularId": 41996,
  "eventId": "GRB 250919A"
}