TITLE: GCN CIRCULAR NUMBER: 30561 SUBJECT: Fermi trigger No 649390368: Global MASTER-Net observations report DATE: 21/07/31 03:00:43 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), 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-IAC robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Spain (IAC Teide Observatory) started inspect of the Fermi GRB210731.09 (trigger No 649390368,02h 23m 52.80s , +22d 58m 48.0s, R=3.07) errorbox 80 sec after trigger time at 2021-07-31 02:14:03 UT, with upper limit up to 16.6 mag. The observations began at zenith distance = 62 deg. The sun altitude is -41.1 deg. The galactic latitude b = -35 deg., longitude l = 150 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1676367 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 90 | 2021-07-31 02:14:03 | MASTER-IAC | (02h 23m 04.58s , +22d 11m 49.0s) | P| | 20 | 15.4 | 90 | 2021-07-31 02:14:03 | MASTER-IAC | (02h 24m 04.02s , +22d 05m 15.3s) | P- | 20 | 15.1 | 147 | 2021-07-31 02:14:55 | MASTER-IAC | (02h 11m 48.12s , +24d 17m 13.8s) | P| | 30 | 15.8 | 197 | 2021-07-31 02:14:55 | MASTER-IAC | (02h 11m 48.12s , +24d 17m 13.7s) | P| | 130 | 16.6 | Coadd 147 | 2021-07-31 02:14:55 | MASTER-IAC | (02h 10m 51.59s , +24d 22m 42.0s) | P- | 30 | 15.5 | 196 | 2021-07-31 02:15:44 | MASTER-IAC | (02h 24m 11.47s , +22d 12m 23.2s) | P| | 30 | 15.7 | 196 | 2021-07-31 02:15:44 | MASTER-IAC | (02h 23m 16.12s , +22d 17m 49.9s) | P- | 30 | 15.4 | 252 | 2021-07-31 02:16:34 | MASTER-IAC | (02h 11m 54.76s , +24d 17m 10.6s) | P| | 40 | 15.9 | 252 | 2021-07-31 02:16:34 | MASTER-IAC | (02h 10m 58.30s , +24d 22m 36.8s) | P- | 40 | 15.6 | 321 | 2021-07-31 02:17:34 | MASTER-IAC | (02h 11m 48.50s , +24d 16m 08.8s) | P| | 60 | 16.1 | 321 | 2021-07-31 02:17:34 | MASTER-IAC | (02h 10m 52.04s , +24d 21m 35.2s) | P- | 60 | 16.0 | 406 | 2021-07-31 02:18:54 | MASTER-IAC | (02h 11m 55.23s , +24d 16m 08.1s) | P| | 70 | 16.2 | 406 | 2021-07-31 02:18:54 | MASTER-IAC | (02h 10m 58.72s , +24d 21m 34.4s) | P- | 70 | 16.0 | 642 | 2021-07-31 02:22:25 | MASTER-IAC | (02h 22m 57.30s , +22d 55m 07.1s) | P| | 120 | 16.1 | 642 | 2021-07-31 02:22:25 | MASTER-IAC | (02h 22m 00.63s , +23d 00m 28.5s) | P- | 120 | 15.9 | 792 | 2021-07-31 02:24:45 | MASTER-IAC | (02h 22m 51.71s , +22d 54m 30.7s) | P| | 140 | 16.3 | 792 | 2021-07-31 02:24:45 | MASTER-IAC | (02h 21m 55.02s , +22d 59m 52.2s) | P- | 140 | 16.1 | 966 | 2021-07-31 02:27:24 | MASTER-IAC | (02h 22m 52.19s , +22d 55m 28.7s) | P| | 170 | 16.4 | 966 | 2021-07-31 02:27:24 | MASTER-IAC | (02h 21m 55.47s , +23d 00m 50.4s) | P- | 170 | 16.3 | 1161 | 2021-07-31 02:30:34 | MASTER-IAC | (02h 22m 56.47s , +22d 54m 27.6s) | P| | 180 | 16.5 | 1161 | 2021-07-31 02:30:34 | MASTER-IAC | (02h 21m 59.72s , +22d 59m 49.4s) | P- | 180 | 16.3 | The observation and reduction will continue. The message may be cited.