TITLE: GCN CIRCULAR NUMBER: 35775 SUBJECT: Swift GRB 240222A: Global MASTER-Net observations report DATE: 24/02/22 18:32:47 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> 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), D. Buckley (South African Astronomical Observatory), 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 Swift GRB 240222A ( P. D'Avanzo et al., GCN 35770) errorbox 33361 sec after notice time and 33382 sec after trigger time at 2024-02-22 18:07:54 UT, with upper limit up to 18.3 mag. Observations started at twilight. The observations began at zenith distance = 50 deg. The sun altitude is -10.1 deg. The galactic latitude b = -12 deg., longitude l = 286 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2383830 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 33473 | MASTER-SAAO | C | 180 | 17.9 | 33473 | MASTER-SAAO | C | 180 | 17.4 | 33672 | MASTER-SAAO | C | 180 | 18.3 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/35775. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...