TITLE: GCN CIRCULAR NUMBER: 35825 SUBJECT: Fermi GRB 240227A: Global MASTER-Net observations report DATE: 24/02/28 04:30:39 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) started inspect of the Fermi GRB 240227A ( Fermi GBM team, GCN 35814) errorbox 48100 sec after notice time and 48133 sec after trigger time at 2024-02-27 18:02:28 UT, with upper limit up to 18.0 mag. Observations started at twilight. The observations began at zenith distance = 32 deg. The sun altitude is -10.2 deg. The galactic latitude b = -39 deg., longitude l = 271 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2387115 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 48163 | 2024-02-27 18:02:28 | MASTER-SAAO | (04h 37m 02.73s , -61d 29m 49.8s) | C | 60 | 17.6 | 48163 | 2024-02-27 18:02:28 | MASTER-SAAO | (04h 55m 01.13s , -61d 40m 45.7s) | C | 60 | 17.3 | 48243 | 2024-02-27 18:03:47 | MASTER-SAAO | (04h 21m 16.28s , -59d 36m 59.5s) | C | 60 | 17.8 | 48243 | 2024-02-27 18:03:47 | MASTER-SAAO | (04h 38m 13.45s , -59d 47m 57.1s) | C | 60 | 17.4 | 48322 | 2024-02-27 18:05:07 | MASTER-SAAO | (04h 21m 36.67s , -63d 25m 43.7s) | C | 60 | 18.0 | 48322 | 2024-02-27 18:05:07 | MASTER-SAAO | (04h 40m 47.01s , -63d 36m 37.9s) | C | 60 | 17.7 | 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/35825. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...