{
  "bibcode": "2023GCN.33691....1L",
  "submitter": "Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>",
  "body": "\nV.Lipunov (Lomonosov MSU), D.A.H.Buckley (SAAO), Ya.Kechin, A.Chasovnikov,\nA.Kuznetsov, N.Tiurina, P.Balanutsa, O.Gress, E.Gorbovskoy, G.Antipov, K.Zhirkov, D.Vlasenko,\nV.Senik, V.Topolev, Yu.Tselik, Siyu Wu (Lomonosov Moscow State University, SAI, Physics Department),\nC.Francile, F. Podesta, C.Lopez, R. Podesta (Observatorio Astronomico Felix Aguilar OAFA),\nR. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias),\nL.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.Corella,\nL.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory),\nN.M.Budnev, O.Ershova (ISU,API),\nA. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),\nA. Gabovich, V.Yurkov (Blagoveschensk Educational State University),\nK.Vetrov, V.Shumkov, T.Pogrosheva\n\nMASTER-SAAO robotic telescope (Global MASTER Net  http://observ.pereplet.ru,Lipunov et al., 2010, Advances in Astronomy, v.2010, 30L)\nlocated in South African Astronomical Observatory\nstarted (Lipunov et al. GCN 33685) inspect of the FERMI GRB230426.85 (trigger 704233744, Wood et al. GCN 33689, Ttrigger 20:28:59.97UT) errorbox\n4359 sec after notice time (4391 sec after trigger time) at 2023-04-26 21:42:11UT with upper limit up to 19.5m,\nsee our cover map https://master.sai.msu.ru/site/master2/observ.php?id=2212931\n\nMASTER OT J023135.16-792104.8 - optical counterpart of GRB 230426A discovery\n2023gwu\n\nMASTER-SAAO auto-detection system found optical counterpart of GRB 230426.85\nat R.A.,Dec(2000) = 02h 31m 35.16s , -79d 21m 04s.8 with unfiltered m_OT=17.4 at\n2023-04-26 21:56:50UT and with optical decay at 10 images\n https://www.wis-tns.org/object/2023gwu .\n\nThere is no any sources in VIZIER database, no any objects in MPC at this time\nand no OT in MASTER database since Dec.2014. We used reference image on\n2018-08-18.99148 UT with  unfiltered mlim=20.6m.\n\nAnalysis will be continued.\n\nDeep photometry and spectral observations are required.\n\nThe message may be cited.",
  "createdOn": 1682616516108,
  "circularId": 33691,
  "eventId": "GRB 230426A",
  "subject": "GRB 230426A: MASTER OT J023135.16-792104.8 optical counterpart discovery"
}