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GCN Circular 23091

GRB 180806.94: MASTER possible OT detection in Fermi GMB trigger 555287944 error box
2018-08-07T10:01:59Z (5 years ago)
Vladimir Lipunov at Moscow State U/Krylov Obs <>
V. Lipunov, N.Tiurina, E. Gorbovskoy,
V.Kornilov, A.Kuznetsov, V.Chazov, I.  Gorbunov,
D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov, D. Vlasenko
Lomonosov Moscow State University,SAI

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

D. Buckley,
South African Astronomical Observatory (SAAO)

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

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

Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

O. Gres, N.M.Budnev , Yu.Ishmuhametova
Irkutsk State University (ISU)

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

MASTER-IAC robotic telescope (MASTER-Net:, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
Spain (IAC Teide Observatory) was pointed to the  GRB180806.94 (GBM 
trigger 555287944) 77 sec 
after notice time and 122 sec after trigger time at 2018-08-06 22:41:02 

The observations made on zenit distance = 78 deg., galactic latitude b 
= -36 deg. The moon (27 % bright part) below the horizon (The altitude of 
the Moon is -36 deg ). The sun  altitude  is -32.4 deg.
The object can be observed till sunrise at 2018-08-07 06:29:57 UT.

We found  OT inside 3 sigma Fermi GBM error box.
The Cover Map is available at

MASTER OT J004613.05+242014.1 discovery

MASTER-IAC auto-detection system discovered OT source at
(RA, Dec) = 00h  46m 13.05s +24d 20m 14.1s  109.3 min after trigger on 
2018-08-07  00:28:20.467 UT .

The OT unfiltered magnitude is 17.0m (limit 17.9m).

The OT is seen in 4 images. There is no minor planet at this place.

We have reference image without OT on 2016-10-05.08846 UT with unfiltered 
magnitude limit 20.2m.

There is no USNO-B1 sources, it means 22mag limit in history and more then 
5m amplitude of current outburst.
There is Sloan star in 2.9"

Spectral observations are required.

The discovery and reference images are available at:

This message can be cited.

[GCN OPS NOTE(07aug18): Per admin, the double use of "GRB" in the 
Subject-line was removed; from "GRB GRB180806.94" to "GRB 180806.94".]
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