TITLE: GCN CIRCULAR NUMBER: 43640 SUBJECT: GRB 260208A : MASTER bright optical transient inside retracted Fermi error-box DATE: 26/02/08 12:35:14 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> R.Podesta (OAFA), V.M.Lipunov (Lomonosov MSU), C. Francile, F.Podesta (OAFA), I.Panchenko (Lomonosov MSU), V.Shumkov (Ozersk), P.Balanutsa, G.Antipov, A.Kuznetsov, E.Gorbovskoy, D.Vlasenko, N. Tiurina, Ya.Kechin, A.Chasovnikov (Lomonosov MSU), D.Svinkin (Ioffe Institute), O.Gress, N.Budnev, R.Mirgazov, A.Diachok, O.Ershova (Irkutsk State University), E. Gonzalez (OAFA, San JuanUni.,Argentina); D.Buckley (SAAO), V.A.Senik, I.Ionov,Yu.Tselik(Lomonosov MSU), A. Sosnovskij (CrAO RAS), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), L.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), V.M.Pillet, R.Rebolo Lopez (The Instituto de Astrofisica de Canarias,Spain) MASTER Global Robotic Net started (Lipunov et al. GCN 43637) Fermi GRB 260208A (GCN 43635) MASTER OT J133855.59+334806.2 discovery MASTER-OAFA auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L ) 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) The OT unfiltered magnitude is 15.2m at 05:33:36UT with GRB decay t^-alpha low at light curve (alpha ~ 1). We observed OT in MASTER-OAFA (Argentina) and MASTER-OAGH (Mexico) (Shumkov et al. https://www.wis-tns.org/object/2026ciw ). We have reference image on 2019-05-24.09972 UT with unfiltered 20.7m. Deep photometry and spectral observations are required. [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. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/43640. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...