GCN Circular 17365

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

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

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

D.Buckley, S. Potter, A.Kniazev, M.Kotze
South African Astronomical Observatory

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 II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in Tunka was pointed to the  GRB150128A 34 sec after notice time 
and 124 sec after trigger time at 2015-01-28 19:01:18 UT. We made several 
20s alert exposures  on the centre of  first  FERMI error box (ra=18 11 00 
dec=+24 21 58 r=11.2). Than we start inspect survey inside this error box 
with average upper limit 18.9 mag.
After more exact coordinates comes MASTER II  robotic telescope located in 
Tunka was pointed on the centre of new FERMI error-box  (ra=18 09 03 
dec=+27 46 48 r=3.320000) 25 sec after notice time and 11821 sec after 
trigger time at 2015-01-28 22:16:15 UT. Than we continued  inspect survey 
inside new error box with upper limit from 18 to 19.
MASTER II  robotic telescope  located in Kislovodsk was starting inspect 
survey on the FERMI   error-box (ra=18 09 03 dec=+27 46 48 r=3.3)  15569 
sec after notice time and 27364 sec after trigger time at 2015-01-29 
02:35:18 UT with average upper limit from 17.5 to 19.

During the inspection of the error box of a long (more than 60 sec) 
multi-peak gamma-ray burst GRB 150128A (Fermi trigger 444164357, INTEGRAL 
SPI-ACS trigger 6874) MASTER-Tunka auto-detection system discovered OT 
source at

(RA, Dec) = 18h 01m 53.15s +25d 43m 23.5s

on 2015-01-28.91546 UT 
(V.Shumkov et al., Atel 7010). The OT unfiltered magnitude is 16.6m 
(limit 
18.6m). The OT is seen in 3 images. There is no minor planet at this 
place. We have reference image without OT on 2011-06-28.73624 UT with 
unfiltered magnitude limit 19.8m. For the description of Global MASTER 
Robotic Net see Lipunov et al., 2010, Advances in Astronomy, article id. 
349171, pp. 1-7. )

MASTER-net coverage map available here:

First  error-box r=11.1d 
http://master.sai.msu.ru/static/GRB150128_net2.png
Second error-box r= 3.3d 
http://master.sai.msu.ru/static/GRB150128_net.png


This message may be cited.

[GCN OPS NOTE(30jan15):  The operator removed the redundnat "GRB"
from the Subject-line and added the "A" suffix in two places
in the body of the Circular.]