[vsnet-grb-info 18390] Short GRB 160821B: MASTER early optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19838
SUBJECT: Short GRB 160821B: MASTER early  optical observations  
DATE:    16/08/22 09:08:42 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov at xray.sai.msu.ru>

R. Rebolo, M. Serra-Ricart, G. Israelian, N. Lodieu
The Instituto de Astrofisica de Canarias

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

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

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

A. Tlatov, V.Senik, D. Dormidontov, A.Parkhomenko
Kislovodsk Solar Station of the Pulkovo Observatory

V.Yurkov, Yu.Sergienko, A.Gabovich
Blagoveschensk Educational State University, Blagoveschensk

Hugo Levato, Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

R.Podesta, C.Mallamaci, C.Lopez, F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA)

MASTER-IAC  twin robotic telescope (MASTER-Net: 
http://observ.pereplet.ru, online view http://161.72.133.2/) 
located in IAC (Tenerife, Spain) was pointed to the 
GRB160821B (Siegel et al., GCN 19833) 34 sec after notice time 
and 53 sec after trigger time at 2016-08-21 22:30:06 UT.
  The alert coordinates altitude was 55 deg. at MASTER-IAC, the Sun 
altitude was -35d, the Moon distance is 90 degrees.

On our first (10s exposure - two images in perpendicular polarizations)
set  we  not found optical transient within SWIFT error-box (Evans et al., GCN 19837)
and at NOT OT position  (Xu et al., GCN 19834) brighter then 16.6.


The resuts of the first 5 minutes observations are:

Id 	Pro.type	UT	Exp.time   Limit	Filt.	  Tube.
                       (Start)     (s)     (5sigma)  (polarizator)

285342   Alert       22:30:06     10       16.6           P-      WEST
285343   Alert       22:30:06     10       16.6           P|      EAST
285342   Alert       22:30:06     10       16.6           P-      WEST
285345   Alert       22:30:43     20       17.1           P|      EAST
285346   Alert       22:31:24     30       17.1           P-      WEST
285347   Alert       22:31:24     30       16.6           P|      EAST
285348   Alert       22:32:08     30       16.6           P-      WEST
285349   Alert       22:32:08     30       16.6           P|      EAST
285350   Alert       22:32:50     40       17.2           P-      WEST
285351   Alert       22:32:50     40       17.0           P|      EAST
285352   Alert       22:33:43     50       17.3           P-      WEST
285353   Alert       22:33:43     50       17.2           P|      EAST
285355	 Alert 	     22:34:46	  70	   17.5	          P-	  WEST
285354	 Alert 	     22:34:46	  70	    0.0	          P|	  EAST

The limit of the coadded west tube images is 18.7 with start time 
22:30:06, finish time =  22:35:56 and mean time = 22:33:01 UT.


The message may be cited.