TITLE: GCN CIRCULAR NUMBER: 38352 SUBJECT: Swift GRB241127.91: Global MASTER-Net OT detection DATE: 24/11/27 21:48:45 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs D. Buckley (South African Astronomical Observatory), V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik, D. Vlasenko, G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), O.A. Gress, N.M. Budnev, O.Ershova (Irkutsk State University, API), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich (Blagoveschensk Educational State University) MASTER-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 GRB241127.91 19 sec after notice time and 35 sec after trigger time at 2024-11-27 21:43:51 UT. On our 3-th (20s exposure) set , obtained 93 sec after tigger time at 2024-11-27 21:44:49 UT, we found 1 optical transient within Swift error-box (ra=327.921 dec=-56.685 r=0.05) brighter than 17.4. T-Tmid Date Time Expt. Ra Dec Mag ---------|---------------------|-------|-----------------|-----------------|------- 103 2024-11-27 21:44:49 20 (21h 51m 32.48s , -56d 39m 55.8s) 15.5 The 5-sigma upper limit has been about 17.4mag The message may be cited.