{
  "bibcode": "2021GCN.30571....1L",
  "body": "V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, \nV.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva,\nD.Kuvshinov,  D. Cheryasov\n(Lomonosov Moscow State University, SAI, Physics Department),\n\nR. Podesta, C.Lopez, F. Podesta, C.Francile \n(Observatorio Astronomico Felix Aguilar OAFA),\n\nR. Rebolo, M. Serra \n(The Instituto de Astrofisica de Canarias),\n\nD. Buckley \n(South African Astronomical Observatory),\n\nO.A. Gres, N.M. Budnev, O.Ershova \n(Irkutsk State University, API),\n\nA. Tlatov, D. Dormidontov \n(Kislovodsk Solar Station of the Pulkovo Observatory),\n\nV. Yurkov, A. Gabovich, Yu. Sergienko \n(Blagoveschensk Educational State University)\n\n\n\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 GRB210731.62 (trigger No 1062273,17h 03m 56.90s , -37d 50m 36.2s, R=0.0013) errorbox  7250 sec after notice time and 7025 sec after trigger time at 2021-07-31 16:47:44 UT, with upper limit up to  19.3 mag. Observations started at twilight.  The observations began at zenith distance = 29 deg. The sun  altitude  is -10.0 deg. \n\nMASTER-Kislovodsk robotic telescope  located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB210731.62 errorbox  10526 sec after notice time and 10301 sec after trigger time at 2021-07-31 17:42:21 UT, with upper limit up to  16.2 mag. Observations started at twilight.  The observations began at zenith distance = 81 deg. The sun  altitude  is -11.5 deg. \n\nMASTER-IAC robotic telescope  located in Spain (IAC Teide Observatory) was pointed to the Swift GRB210731.62 errorbox  21230 sec after notice time and 21005 sec after trigger time at 2021-07-31 20:40:45 UT, with upper limit up to  17.1 mag. Observations started at twilight.  The observations began at zenith distance = 67 deg. The sun  altitude  is -10.4 deg. \n\nThe galactic latitude b =  2 deg., longitude l = 348 deg.\n\n\nReal time updated cover map and OT discovered available here: \nhttps://master.sai.msu.ru/site/master2/observ.php?id=1676885\n\nWe obtain a following upper limits.  \n\nTmid-T0  |          Site       |Filt.| Expt. | Limit| Comment\n_________|_____________________|_____|_______|______|________\n\n    7115 |         MASTER-SAAO |   C |   180 | 18.1 |        \n    7315 |         MASTER-SAAO |   C |   180 | 18.5 |        \n    7684 |         MASTER-SAAO |   C |   180 | 18.9 |        \n    8054 |         MASTER-SAAO |   C |   180 | 19.0 |        \n    8984 |         MASTER-SAAO |   C |   180 | 19.0 |        \n    9184 |         MASTER-SAAO |   C |   180 | 19.3 |        \n    9706 |         MASTER-SAAO |   C |   180 | 19.0 |        \n   10069 |         MASTER-SAAO |   C |   180 | 18.8 |        \n   10392 |   MASTER-Kislovodsk |   C |   180 | 15.8 |        \n   10392 |   MASTER-Kislovodsk |   C |   180 | 16.1 |        \n   10848 |         MASTER-SAAO |   C |   180 | 18.6 |        \n   12753 |         MASTER-SAAO |   C |   180 | 18.4 |        \n   14565 |         MASTER-SAAO |   C |   180 | 16.7 |        \n   16389 |         MASTER-SAAO |   C |   180 | 14.4 |        \n   17476 |   MASTER-Kislovodsk |   C |   180 | 15.9 |        \n   17476 |   MASTER-Kislovodsk |   C |   180 | 16.3 |        \n   18241 |         MASTER-SAAO |   C |   180 | 15.3 |        \n   20059 |         MASTER-SAAO |   C |   180 | 16.9 |        \n   21096 |          MASTER-IAC |   C |   180 | 15.0 |        \n   21096 |          MASTER-IAC |   C |   180 | 14.8 |        \n   21296 |          MASTER-IAC |   C |   180 | 16.3 |        \n   21296 |          MASTER-IAC |   C |   180 | 16.0 |        \n   21876 |         MASTER-SAAO |   C |   180 | 17.6 |        \n   22460 |          MASTER-IAC |   C |   180 | 16.9 |        \n   22460 |          MASTER-IAC |   C |   180 | 16.4 |        \n   23835 |          MASTER-IAC |   C |   180 | 17.1 |        \n   23835 |          MASTER-IAC |   C |   180 | 16.6 |        \n   23876 |         MASTER-SAAO |   C |   180 | 18.0 |        \n   25874 |         MASTER-SAAO |   C |   180 | 18.1 |        \nFilter C is a clear (unfiltred) band. \n\n\nThe observation and reduction will continue. \nThe message may be cited.",
  "circularId": 30571,
  "createdOn": 1627828639000,
  "email": "lipunov@xray.sai.msu.ru",
  "subject": "Swift GRB210731.62: Global MASTER-Net observations report",
  "submitter": "Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>",
  "eventId": "GRB 210731.62"
}