Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
Introducing Einstein Probe, Astro Flavored Markdown, and Notices Schema v4.0.0. See news and announcements

GCN Circular 21291

GRB 170705A: MASTER-OAFA early OT observations
2017-07-05T09:26:46Z (7 years ago)
Vladimir Lipunov at Moscow State U/Krylov Obs <>
V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, D.Kuvshinov, A.V.Krylov,
I.Gorbunov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University, Sternberg Astronomical Institut of MSU

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

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: 
located in OAFA was pointed to the  GRB170705A (Starling et al.,GCN #21289)
24 sec after notice time  and 38 sec after trigger time at 2017-07-05 
02:46:27 UT  at high zenit distance.
On our first (10s  exposure)  unfiltered exposition we haven`t found 
optical transient  within SWIFT error-box  (ra=191.704 dec=18.2928 r=0.05)
brighter than 15.0.

We marginally found OT at Swift UVOT position (Starling et al.,GCN #21289) 
on coaded image ID=79921 with m ~ 17.0.

  ID       DATE      UT     Exp      Type         Limit        Note

79817 2017-07-05 02:46:27  10    Alert (SWIFT)   15.0          no
79921 2017-07-05 02:46:27 190 SumAlert (SWIFT)   16.9 79817+79825+79820+79818 
79818 2017-07-05 02:47:20  20    Alert (SWIFT)   15.8         yes
79819 2017-07-05 02:48:24  30    Alert (SWIFT)   15.9          no
79820 2017-07-05 02:49:38  50    Alert (SWIFT)   16.2         yes
79822 2017-07-05 02:51:13  60    Alert (SWIFT)   16.3          no
79824 2017-07-05 02:52:57  90    Alert (SWIFT)   16.5          no
79825 2017-07-05 02:55:11 110    Alert (SWIFT)   16.4         yes
79826 2017-07-05 02:57:46 140    Alert (SWIFT)   16.4          no
79827 2017-07-05 03:00:48 180    Alert (SWIFT)   16.7          no
79829 2017-07-05 03:04:32 180    Alert (SWIFT)   16.3          no 
79830 2017-07-05 03:08:12 180    Alert (SWIFT)   16.0          no

The unfiltered magnitude is about ~17 m .
The big differences with UVOT magnitude may be connected with high GRB
redshift because our CCD is more red.

The observations made on zenit distance = 79 degrees, galaxy latitude b = 
81 degree. The moon (86 % bright part) is 66 degrees above the horizon. 
The distance between  moon and  object is 56
The sun  altitude  is -63.1 degree.
The object can be observed till 2017-07-05 03:46:20 .

The message may be cited.
Looking for U.S. government information and services? Visit