TITLE:   GCN CIRCULAR
NUMBER:  42067
SUBJECT: Fermi/SVOM GRB 251002A : MASTER OT earlier detection in 2 polarization filters
DATE:    25/10/03 01:27:07 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>


V.Senik, V. Lipunov, E.Gorbovskoy, A.Kuznetsov, I.Panchenko, P.Balanutsa, N.Tiurina, A.Sankovich, G.Antipov,Yu. Tselik, A. Sosnovskiy,  M.Shilova, A.Chasovnikov, V.Topolev,
K.Zhirkov, Ya.Kechin, V.Senik, D.Vlasenko(Lomonosov MSU, SAI, Moscow),
A.Sosnovskij (CrAO RAS),
R.Podesta, C.Francile,  F. Podesta, E. Gonzalez (OAFA, San Juan  Uni.,Argentina);
D.Buckley, (SAAO, South Africa)
O.Gress, N.Budnev (ISU, Irkutsk),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity),
V.M.Pillet, R.Rebolo Lopez (The Instituto de Astrofisica de Canarias, Spain),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez,J.Martinez,A.R.Corella,
L.H.Rodriguez (INAOE, Guillermo Haro  Astrophysic Observatory, Mexico)

The MASTER-Kislovodsk robotic telescope of the MASTER Global Robotic Net [1], [2]
started Fermi GRB 251002A (trigger 781128896, Ttrigger=2025-10-02 20:14:51UT)
at 2025-10-02 20:19:42 (Lipunov et al. GCN 42059, cover map and OT
https://master.sai.msu.ru/site/master2/event.php?id=3005541&action=12&SAT=SVOM&DAYS=2++  )
 in two mutually perpendicular polarization filters.

There is MASTER OT J005537.81-053401.0 since the first image with
unfiltered m_OT~17.2 at 2025-10-02 20:22:09.308(not first time)
with preliminary detected polarization.

This OT was first publishied (discovered) by SVOM (GCN 42061), and also by LCO (Turpin et al. GCN 42062), FREM-ORM (Jelinek et al. GCN 42063), SAO RAS (Moskvitin et al. GCN 42065) and BOOTES (Perez-Garcia et al. GCN 42066)

Observations and reduction will be continued.

[1] Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L
[2] V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina,A.S.Kuznetsov
 2023,  Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp.
http://www.pereplet.ru/lipunov/625.html#625