GCN Circular 23361

V.Lipunov, E. Gorbovskoy, N.Tiurina, V.Kornilov, A.Kuznetsov,
D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov,  D.Vlasenko
Lomonosov Moscow State University,SAI

V.B. Petkov, M.M. Boliev, A.N. Kurenya,
Baksan Neutrino Observatory, Institute for Nuclear Research of RAS,
Moscow, Russia

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

D. Buckley,
South African Astronomical Observatory (SAAO)

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

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)

H.Levato,
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)

Global MASTER Robotic Net started new follow up optical observations 
of high energy (> 1Gev) neutrino from Baksan Neutrino Observatory Alerts 
(Petkov et al., Physics of Particles and Nuclei, 2015,Vol. 46, pp. 201-204.).


MASTER-Tunka robotic telescope (MASTER-Net: Lipunov et al., 2010, Advances 
in Astronomy, vol. 2010, 30L   http://observ.pereplet.ru)
located near Baykal Lake (Russia) started  Baksan Neutrino 
Observatory  BNO181021.79  ( RA_2000=124.3,+08.3, 
error-box=03deg,  TriggerTime=2018-10-21 19:09:43UT, 
NoticeTime=19:50:20.18 UT) alert observations at 2018-10-21 19:50:49 UT 
(20 sec after notice time,  2466 sec after trigger time).
  The 5-sigma upper limit on our 540s images is 19.2 mag.

Observations started, when
Object_Altitude: 28.56 deg
Sun_Altitude: -35.34 deg
Moon_Altitude: 4.43 deg, Dist. to Moon: 128.694199 deg, Lunar disk: 0.91
Gal. latitude: 23.34deg, Gal. longitude: 215.67deg



MASTER-Tavrida robotic telescope, located in Lomonosov MSU, SAI Crimea 
astronomical station,
started BNO181021.79 alert  inspection  at 2018-10-21 23:54:02UT (17059 
sec after  trigger time)
and observed till 2018-10-22 00:21:59UT.
  The 5-sigma upper limit on our 540s images is 19.0.

Observations started, when
Object_Altitude: 25.90 deg
Sun_Altitude: -43.89 deg
Moon_Altitude:13.64 deg, Dist. to Moon:  126.65 deg, Lunar disk: 0.92
Gal. latitude: 23.34deg, Gal. longitude: 215.67deg


MASTER-SAAO robotic telescope, located in South African Astronomical 
Observatory,
started BNO181021.79 alert inspection  at 2018-10-22 01:50:11UT (20528 sec 
after trigger time).
and observed it till 2018-10-22 03:00:55UT  .
  The 5-sigma upper limit on our 540s images is 20.0.

Observations started, when
Object_Altitude: 30.8 deg
Sun_Altitude: -23.59 deg
Moon_Altitude: 10.92 deg, Dist. to Moon: 125.65 deg, Lunar disk: 0.92
Gal. latitude: 23.34deg, Gal. longitude: 215.67deg

There are two QSOs inside neutrino error box. First of them has RA,DEC = 
08 10 26.42 +10 10 40.99 in 0.421" with z=2.50589 (unfiltered MASTER 
magnitude m =  17.2 ). 
But there is no significant variability of its brightness since 2011-11-26 
20:43:35.857UT in MASTER-Tunka database.

Second one has coordinates 08 15 29.47	+09 54 40.7 with Z=1.7 and 
rmag=20.04 .


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