TITLE: GCN CIRCULAR NUMBER: 37384 SUBJECT: Fermi trigger No 747163821: Global MASTER-Net observations report DATE: 24/09/04 18:16:16 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 GRB240904.73 (trigger No 747163821,14h 29m 21.60s , -64d 25m 12.0s, R=2) errorbox 39 sec after notice time and 70 sec after trigger time at 2024-09-04 17:31:27 UT, with upper limit up to 16.3 mag. Observations started at twilight. The observations began at zenith distance = 44 deg. The sun altitude is -15.1 deg.

The galactic latitude b = -4 deg., longitude l = 314 deg.

Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2589350

We obtain a following upper limits.

Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________

76 | 2024-09-04 17:31:27 | MASTER-SAAO | (14h 29m 23.97s , -64d 24m 25.2s) | C | 10 | 16.3 | Filter C is a clear (unfiltred) band.

The observation and reduction will continue. The message may be cited.

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