[vsnet-grb-info 27145] GRB 210104A: MASTER OT rebrightening detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29248
SUBJECT: GRB 210104A: MASTER OT rebrightening  detection
DATE:    21/01/04 22:48:33 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov at xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, N.Tiurina,P.Balanutsa,F.Balakin, 
V.Vladimirov, A.Kuznetsov,K.Zhirkov,D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik,
A.Chasovnikov,A.Pozdnyakov,V.Topolev, D.Cheryasov(Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico FelixAguilar OAFA),
R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias),
D. Buckley (South African Astronomical Observatory),
O.A. Gres, N.M. Budnev (Irkutsk State University, API),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov, Yu. Sergienko (Blagoveschensk Educational StateUniversity)

MASTER-Tavrida robotic telescope
(Global MASTER-Net http://observ.pereplet.ru, Lipunov et al. 2010, Advances in Astronomy,v.2010,30L)
started (Lipunov et al. GCN 29239)
inspect of Fermi and Swift GRB 210104A (Fermi GCN 29232, 29246;Ttrig=11:26:59;
Swift GCN Troja et al. GCN 29233,Beardmore et al. GCN 29245, Breeveld et al. GCN 29247 ;
Barthelmy https://gcn.gsfc.nasa.gov/other/210104A.gcn3 )
at sunset at Lomonosov MSU Crimean observatory at 2021-01-04 15:19:29 UT.

We detect rebrightening of OT (discovered by Swift GCN 29233 and observed by Xin et al., GCN Circ. 29235; Hosokawa etal. GCN 29237; Kim et al. GCN 29238;
Lipunov et al. GCN 29239, Horiuchi et al. GCN 29241, Breeveld et al. GCN 29247)
MASTER OT J065505.45+644035.0 at 2021-01-04 15:48:32UT with unfiltered 
m_OT=17.3.

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