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GCN Circular 17245

Subject
GRB 141225A: MASTER-SAAO OT light curve
Date
2014-12-28T12:16:57Z (9 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
D.Buckley, S. Potter, A. Kniazev, M. Kotze
South African Astronomical Observatory

E. Gorbovskoy,V. Lipunov, N.Tyurina, P.Balanutsa, D.Denisenko, 
M.Pruzhinskaya, A.Kuznetsov, V.Kornilov, D.Kuvshinov,
Lomonosov Moscow State University, Sternberg Astronomical Institute

O.Gres, K.Ivanov,  S.Yazev, N.M.Budnev,  V.A.Poleshchuk
Irkutsk State University

V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov
Blagoveschensk Educational State University

A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik
Kislovodsk Solar Station of the Pulkovo Observatory

V.Krushinsky, I.Zalozhnih,  A. Popov
Ural Federal University, Kourovka

H. Levato and C. Saffe
Instituto de Ciencias Astronomicas de la Tierra y del Espacio (ICATE),
San Juan, Argentina

C. Mallamacci, C. Lopez and F. Podest
Observatorio Astronomico Felix Aguilar (OAFA), San Juan National University, 
Argentina

MASTER-SAAO  robotic telescope (MASTER-Net: http://observ.pereplet.ru)
installed several days ago  in South African Astronomical
Observatory (Sutherland) was automatically  pointed
to the  Swift and Fermi GRB 141225A (Avanzo  et. al. GCN 17229Not found
 
 
).
Firstly MASTER-SAAO pointed by FERMI coordinates and made first exposure 28 
sec after FERMI trigger at  2014-12-25 23:02:28 UT (Buckley et al., 
17233).
Then MASTER-SAAO pointed to the  Swift coordinates 20 sec after  Swift notice 
time and 113 sec after trigger time at 2014-12-25 23:03:00 UT.

The results of our photometery are:

   Start   T-T_mid  Exp.  Mag   Coadd

   UT         s      s    unf    ?

23:03:00    123    20    17.1   no
23:03:34    161    30    17.3   no
23:04:15    207    40    17.5   no
23:05:05    263    50    17.7   no
23:06:06    329    60    18.9   no
23:07:17    405    70    18.7   no
23:08:38    556   200    19.0    2
23:12:19    823   290    19.8    2
23:17:31   3161  3600    21.3   20



Our  band  is well described by a parity 0.8R+0.2B (USNO B1).
The light curve from 113 to 300 power low index is about
  alpha ~= 0.76+-0.10  (F ~ t_-alpha)

and alpha =~ 1.51 from 400 to 1500 .
We see ~1 magnitude depression  at 329 sec.

The magnitudes in the table are not corrected for the Galactic extinction
because its less than the our errors (Schlegel et al. 1998).

The light curve is available at 
http://master.sai.msu.ru/static/GRB/GRB141225A.png

This message may be cited.