TITLE: GCN CIRCULAR NUMBER: 27175 SUBJECT: Fermi trigger No 604213554: Global MASTER-Net observations report DATE: 20/02/24 06:30:11 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov, D. Cheryasov (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University) MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB200224.21 (trigger No 604213554,11h 51m 36.00s , -28d 52m 12.0s, R=3.08) errorbox 548 sec after notice time and 579 sec after trigger time at 2020-02-24 05:15:28 UT, with upper limit up to 20.2 mag. The observations began at zenith distance = 13 deg. The sun altitude is -48.7 deg. The galactic latitude b = 32 deg., longitude l = 288 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1296022 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 640 | 2020-02-24 05:15:28 | MASTER-OAFA | (11h 50m 33.57s , -28d 44m 47.1s) | C | 120 | 19.4 | 800 | 2020-02-24 05:15:28 | MASTER-OAFA | (11h 50m 33.57s , -28d 44m 47.1s) | C | 440 | 20.2 | Coadd 801 | 2020-02-24 05:18:00 | MASTER-OAFA | (11h 50m 35.98s , -28d 44m 56.4s) | C | 140 | 19.5 | 992 | 2020-02-24 05:20:51 | MASTER-OAFA | (11h 50m 30.37s , -28d 46m 03.0s) | C | 180 | 19.8 | 1204 | 2020-02-24 05:24:23 | MASTER-OAFA | (11h 50m 36.20s , -28d 45m 57.3s) | C | 180 | 19.8 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [GCN OPS NOTE(24feb20): This is the fourth Circular in the sequence of 8 circulars which were all (except this one) labeled A because of the sequence assigner being offline. In the normal lettering method this would be burst B.]