TITLE: GCN CIRCULAR NUMBER: 36219 SUBJECT: Swift GRB 240421B: Global MASTER-Net observations report DATE: 24/04/22 00:24:46 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-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB 240421B ( M. A. Williams et al., GCN 36208) errorbox 52346 sec after notice time and 52368 sec after trigger time at 2024-04-22 00:15:42 UT, with upper limit up to 16.5 mag. The observations began at zenith distance = 70 deg. The sun altitude is -20.3 deg.
The galactic latitude b = -22 deg., longitude l = 27 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2430219
We obtain a following upper limits.
Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________
52459 | MASTER-Kislovodsk | C | 180 | 15.8 | 52459 | MASTER-Kislovodsk | C | 180 | 16.5 | Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
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