[vsnet-grb-info 19317] Swift Trigger 748858: MASTER-OAFA early optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21014
SUBJECT: Swift Trigger 748858: MASTER-OAFA  early  optical observations 
DATE:    17/04/19 13:58:58 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov at xray.sai.msu.ru>

R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA) , 
National University of San Juan, Argentina

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

V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina, 
A.V.Krylov, I.Gorbunov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko

Lomonosov Moscow State University, Sternberg Astronomical Institut of MSU

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

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

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

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

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

MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in OAFA was pointed to the  possible grb's Swift Trigger 748858 17 
sec after notice time and 93 sec after trigger time at 2017-04-19 07:45:09 
UT. On our first (20s exposure)  set we haven`t found optical transient 
within SWIFT error-box (ra=199.85 dec=15.4703 r=0.05) (M. H. Siegel et al. 
GCN 21011).

The 5-sigma upper limit has been about 18.7 mag

Maximal limit of coadded images starting at 2017-04-19 07:45:09 (93 s 
after trigger time, 5000s exposure) is 19.7 mag.

The observations made on zenit distance = 71 degrees, galaxy latitude b = 
76 degree.
The moon (51 % bright part) is 47 degrees above the horizon. The distance 
between  moon and  object is 104
The sun  altitude  is -41.8 degree.
The object  observed till 2017-04-19 09:29:17


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