GCN Circular 31620

O.Gress & N.M. Budnev (Irkutsk State University, API),
V. Lipunov, N.Tiurina,  K.Zhirkov, A.Kuznetsov, P.Balanutsa, 
A.Chasovnikov, K.Zhirkov, N.Tiurina, G.Antipov, E.Gorbovskoy, D. Vlasenko, 
V.Senik, Ya.Kechin, V.Topolev
(Lomonosov MSU,SAI,PhysicsDepartment),
A. Gabovich & V.Yurkov (Blagoveschensk Educational StateUniversity)
L. Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J. Martinez,
A.R.Corella, L.H.Rodriguez (INAOE, OAGH),
C.Francile, R. Podesta, F. Podesta (OAFA),
R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias),
D. Buckley (South African Astronomical Observatory),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),


MASTER Global Robotic Net (Lipunov et al. 
2010, Advances in Astronomy, v.2010, 30L) started IceCube 
20220220.60/AMON NuEm-220220A alert (GCN  #31615, 
https://gcn.gsfc.nasa.gov/other/icecube_220220A.gcn3
Not found
 
 
 ) 
optical observations  25 sec after notice time (618s after trigger 
time)
at 2022-02-20 14:29:55 UT at MASTER-Amur (Lipunov et al. GCN #31616) and 
observed it in MASTER-OAGH (Mexico), -SAAO (South Africa), -OAFA 
(Argentina), see cover map 
https://master.sai.msu.ru/site/master2/event.php?id=1889478 <br>

There is a blazar 5BZBJ1442+1200 (RA=220.70117d DEC=12.01119d) 1.5 degrees 
from the center of the event that shows moderate dimming that started 10 
days before the neutrino according to public ATLAS data 
(https://fallingstar-data.com/forcedphot/queue/169872/plot.pdf).<br>

There was IC-201014A in this region (IC GCN #28624, MASTER GCN #28627 ).

Due to this dimming we are inclined to believe that  5BZBJ1442+1200 might 
be a source of NuEM-220220A even though it is largely outside the 
error-box.

The analysis will be continued.
Additional observations are planned.