[vsnet-grb-info 21260] GRB 181020A: Global MASTER Net OT observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23359
SUBJECT: GRB 181020A: Global MASTER Net OT  observations 
DATE:    18/10/21 18:05:37 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov at xray.sai.msu.ru>

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

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

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

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

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

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

MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
South Africa (South African Astronomical Observatory) was starting survey 
on the SWIFT  GRB181020.79 error-box (ra=00 55 55.78 dec=-47 22 52 
r=0.05; Moss et all., GCN #23349; Axelsson et al., Fermi LAT, GCN #23350) 
7550 sec after notice time and 7572 sec 
after trigger time at 2018-10-20 
21:06:45 UT. The delay connected with weather condition around trigeer 
time. The 5-sigma upper 
limit on our first (540s exposure) coadd set is about 19.5 mag

We see possible nonmonotonic behaviour OT detected UVOT ( Moss et all., 
GCN #23349;). More accurate (handmade) reduction will be coming.

The automatic OT LC is available at 
http://observ.pereplet.ru/images/GRB181020A_LC.jpg

The galactic latitude b = -70 deg., longitude l = 300 deg.
The observations made on zenit distance = 16 deg.The moon (85 % bright 
part) is 60 deg. above the horizon. The distance between  moon and  object 
is 45 degrees.
The sun  altitude  is -43.7 deg.
The object can be observed till sunrise at 2018-10-21 03:49:44

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