{
  "bibcode": "2025GCN.41157....1R",
  "eventId": "GRB 250725A",
  "circularId": 41157,
  "body": "\nP. Rudominskaya (Lomonosov, MSU),\nC.Francile,  F. Podesta, R.Podesta, E. Gonzalez (OAFA),\nV.Lipunov (Lomonosov MSU), E.Gorbovskoy,\nA.Kuznetsov, G.Antipov, P.Balanutsa, A.Chasovnikov, N.Tiurina,\nV.Topolev, K.Zhirkov, Ya.Kechin, V.Senik, D.Vlasenko (Lomonosov MSU),\nO.Gress, N.Budnev (ISU),\nA.Sosnovskij (Crao RAS),\nA. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),\nA. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity),\nR.Rebolo (The Instituto de Astrofisica de Canarias),\nL.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez,\nJ.Martinez,A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro  Astrophysics\nObservatory\n\nMASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the  GRB250725.08 26 sec after notice time and 45 sec after trigger time at 2025-07-25 01:52:22 UT. On our first (10s exposure)  set we  found 1 optical transient within Swift error-box (ra=35.3833 dec=-82.7836 r=0.05) brighter than  17.7.\n\n\n T-Tmid      Date      Time       Expt.        Ra                Dec Mag\n---------|---------------------|-------|-----------------|-----------------|-------\n      50   2025-07-25 01:52:22      10   (02h 21m 55.67s , -82d 47m 28.1s) 15.8\nThe 5-sigma upper limit has been about  17.7mag\n\nThe automatical light curve is the very fast fall F ~ t^-2\nThis very similar to short GRB behavior.\nThe large optical telescope observation is very welcome!\nThe message may be cited.\n\n",
  "subject": "GRB 250725A: MASTER-OAFA  optical detection of  very fast afterglow",
  "submitter": "Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>",
  "createdOn": 1753433512653,
  "submittedHow": "email"
}