[vsnet-grb-info 21861] GRB190305A: MASTER Global Robotic Net optical observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23960
SUBJECT: GRB190305A: MASTER Global Robotic Net  optical observation 
DATE:    19/03/12 15:34:50 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov at xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, N.Tyurina, V.Kornilov, D.Vlasenko, V.Vladimirov,  D.Zimnukhov,
A.Kuznetsov, P.Balanutsa, A. Chasovnikov, V.Topolev, D.Kuvshinov (Lomonosov Moscow State University, SAI, Physics Department),

O. Gress, N.M. Budnev, O.Ershova, Yu.Ishmuhametova, S.Yazev (Applied Physics Institute, Irkutsk State University),

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

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

D. Buckley (South African Astronomical Observatory),

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

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

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

MASTER Global Robotic Net (http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, v. 2010, 30L)
automatically pointed to MAXI GRB 190305A error box (00 45 17 dec=-50 07 18, r=1) (Nakahira et al. GCN 23933),
also detected by Ursi A. et al. GCN 23930,Xiao et al. GCN 23934, Svinkin et al. 23936, Kozlova et al. GCN 23939, Morita et al. GCN 23944
https://gcn.gsfc.nasa.gov/other/190305A.gcn3 ).

MASTER-SAAO (located in South African Astronomical Observatory)
automatically started GRB 190305A observations 7776 sec after notice time 
(18080 sec after trigger time) at 2019-03-05 18:09:03 UT
with unfiltered magnitude limit 19.6 (5 sigma).

Observations started when
Object_Altitude was 27.3 deg.
Sun_Altitude: -13.7 deg.
Moon_Altitude: -35.3, Dist. to Moon: 46.37deg.

MASTER-OAFA robotic telescope (located in Argentina , OAFA observatory of San Juan National University)
was pointed to the  MAXI GRB190305.55 1 day 38560 sec after trigger time at 2019-03-06 23:50:23 UT,
with unfiltered magnitude limit 17.5 mag.

Observations started at twilight:
Object_Altitude: 29.15deg.
Sun_Altitude: -10.7 deg.

The cover map is available at 
http://master.sai.msu.ru/static/GRB190305A/MASTERGRB190305A.jpg

We analysed Swift-XRT afterglow position (D'Ai et al. GCN 23945)
RA,Dec(2000)=00h 46m 30.38s -50d 20' 55.1".

There is no OT during MASTER alert observations, but there is  optical 
source in MASTER database on 2018-08-08 22:01:51UT with m_OT=20.1(mlim=20.3).

There is GALEX source in 1.836"	,
there is also a source in USNO-B1 in 0.982" with B2=18.08, R2=20.3 in 1984.6y.

The observation and reduction will be continued.
The message may be cited.