{
  "circularId": 43640,
  "submitter": "Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>",
  "eventId": "GRB 260208A",
  "submittedHow": "email",
  "createdOn": 1770554114305,
  "subject": "GRB 260208A : MASTER bright optical transient inside retracted Fermi error-box",
  "bibcode": "2026GCN.43640....1P",
  "body": "\nR.Podesta (OAFA), V.M.Lipunov (Lomonosov MSU),\nC. Francile, F.Podesta (OAFA),\nI.Panchenko (Lomonosov MSU), V.Shumkov (Ozersk),  P.Balanutsa, G.Antipov, A.Kuznetsov, E.Gorbovskoy, D.Vlasenko, N. Tiurina, Ya.Kechin, A.Chasovnikov (Lomonosov MSU),\nD.Svinkin (Ioffe Institute),\nO.Gress, N.Budnev, R.Mirgazov, A.Diachok, O.Ershova (Irkutsk State University),\nE. Gonzalez (OAFA, San JuanUni.,Argentina);\nD.Buckley (SAAO),\nV.A.Senik, I.Ionov,Yu.Tselik(Lomonosov MSU),\nA. Sosnovskij (CrAO RAS),\nA. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),\nL.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino, J.Martinez, A.R.Corella, J.G.Tanori,  L. F. Villalobos, L.H.Rodriguez (INAOE, Guillermo Haro AstrophysicObservatory, Mexico),\nV.M.Pillet, R.Rebolo Lopez (The Instituto de Astrofisica de Canarias,Spain)\n\nMASTER Global Robotic Net started (Lipunov et al. GCN 43637) Fermi GRB 260208A (GCN 43635)\n\nMASTER OT J133855.59+334806.2 discovery\n\nMASTER-OAFA auto-detection system ( Lipunov et al., \"MASTER Global Robotic Net\", Advances in Astronomy, 2010, 30L )\n discovered OT source at (RA, Dec) = 13h 38m 55.59s +33d 48m 06.2s during Fermi trigger 792220053 inspection (also known as GRB 260208A, retracted by Fermi team)\n\nThe OT unfiltered magnitude is 15.2m at 05:33:36UT with GRB decay t^-alpha low at light curve (alpha ~ 1).\nWe observed OT in MASTER-OAFA (Argentina) and MASTER-OAGH (Mexico) (Shumkov et al. https://www.wis-tns.org/object/2026ciw ).\n\nWe have reference image on 2019-05-24.09972 UT with unfiltered 20.7m.\n\nDeep photometry and spectral observations are required.\n\n[1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023,  Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp.\nhttp : // www.pereplet.ru/lipunov/625.html"
}