[vsnet-grb-info 19794] GRB 170906A: MASTER-OAFA (Argentina) early automatic OT detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21830
SUBJECT: GRB 170906A: MASTER-OAFA (Argentina) early automatic  OT detection
DATE:    17/09/06 09:01:51 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov at xray.sai.msu.ru>

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

R. Podesta, Carlos Lopez and F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA)

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

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


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

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

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


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

MASTER-OAFA  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in Argentina was pointed to the  Swift  GRB170906A (Siegel rt al. 
GCN21821)  44 sec after trigger time at 2017-09-06 00:43:56 UT with 10 
sec exposition.
Robot  found 1  optical transient within SWIFT error-box (ra=13:35:49.19 
dec=-47:06:01.9  r=0.61(90%)) at

RA, DEC = 13h 35m 49.3s , -47d  6m 02.7s

We see OT brightenning from unfiltered mag  15.6 up to 14.4 at 2017-09-06 
00:50:54  UT (midle time).

The 5-sigma upper limit on the single images has been about 16.8mag

This OT was also detected by UVOT (Siegel et al GCN 21821) and REM
(Covino et al. GCN 21825).

The observations made on zenit distance = 64 degrees, galaxy latitude b = 
15 degree.
The moon (100 % bright part) is 35 degrees above the horizon. The distance 
between  moon and  object is 113
The sun  altitude  is -31.7 degree.
The object can be observed till 2017-09-06 04:04:24.

The message may be cited.