{
  "createdOn": 1748665040769,
  "bibcode": "2025GCN.40587....1L",
  "subject": "Swift GRB 250530C: Global MASTER-Net observations report",
  "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) was pointed to the Swift GRB 250530C ( R. Caputo et al., GCN 40585) errorbox  31007 sec after notice time and 31055 sec after trigger time at 2025-05-31 03:36:18 UT, with upper limit up to  18.6 mag. The observations began at zenith distance = 79 deg. The sun  altitude  is -23.6 deg. \n\nThe galactic latitude b = -51 deg., longitude l = 216 deg.\n\n\nReal time updated cover map and OT discovered available here: \nhttps://master.sai.msu.ru/site/master2/observ.php?id=2887090\n\nWe obtain a following upper limits.  \n\nTmid-T0  |          Site       |Filt.| Expt. | Limit| Comment\n_________|_____________________|_____|_______|______|________\n\n   31086 |         MASTER-SAAO |   C |    60 | 18.6 |        \n   31086 |             MASTER- |   C |    60 | 13.1 |        \nFilter C is a clear (unfiltred) band. \n\n\nThe observation and reduction will continue. \nThe message may be cited.\n",
  "eventId": "GRB 250530C",
  "submitter": "Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>",
  "circularId": 40587,
  "submittedHow": "email"
}