{
  "editedOn": 1747747144933,
  "bibcode": "2025GCN.40490....1L",
  "subject": "Swift GRB 250520A: Global MASTER-Net observations report",
  "submittedHow": "email",
  "createdOn": 1747709811335,
  "eventId": "GRB 250520A",
  "version": 2,
  "circularId": 40490,
  "format": "text/plain",
  "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 GRB250520.11 (trigger No 1315630,18h 49m 04.32s , -11d 50m 49.2s, R=0.05) errorbox  23 sec after notice time and 46 sec after trigger time at 2025-05-20 02:43:03 UT, with upper limit up to  17.0 mag. The observations began at zenith distance = 25 deg. The sun  altitude  is -33.7 deg. \n\nThe galactic latitude b = -5 deg., longitude l = 22 deg.\n\n\nReal time updated cover map and OT discovered available here: \nhttps://master.sai.msu.ru/site/master2/observ.php?id=2875870\n\nWe obtain a following upper limits.  \n\nTmid-T0  |          Site       |Filt.| Expt. | Limit| Comment\n_________|_____________________|_____|_______|______|________\n\n      52 |         MASTER-SAAO |   C |    10 | 16.3 |        \n      80 |         MASTER-SAAO |   C |    10 | 16.3 |        \n     115 |         MASTER-SAAO |   C |    20 | 16.4 |        \n     159 |         MASTER-SAAO |   C |    30 | 16.7 |        \n     213 |         MASTER-SAAO |   C |    40 | 16.7 |        \n     277 |         MASTER-SAAO |   C |    50 | 16.7 |        \n     351 |         MASTER-SAAO |   C |    60 | 17.0 |        \n     430 |         MASTER-SAAO |   C |    60 | 16.9 |        \nFilter C is a clear (unfiltred) band. \n\n\nThe observation and reduction will continue. \nThe message may be cited.\n",
  "submitter": "Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>",
  "editedBy": "Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Vladimir Lipunov at Lomonosov Moscow State University <lipunov@sai.msu.ru>"
}