TITLE: GCN CIRCULAR NUMBER: 40042 SUBJECT: IceCube-250330A: MASTER detection of PKS 2032+107 blazar flare with Zhirkov effect DATE: 25/04/04 10:05:05 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> K. Labzina, K.Zhirkov, V.Lipunov, E.Gorbovskoy, A.Kuznetsov, G.Antipov, D.Vlasenko, A.Kuznetsov, N.Tyurina, P.Balanutsa, A.Chasovnikov, V.Topolev, Ya.Kechin, V.Senik (Lomonosov MSU), O.Gress, N.Budnev, O.Ershova (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), D.Buckley (SAAO), A.Sosnovskij (Crao RAS), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro AstrophysicsObservatory) MASTER-OAFA robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Argentina (OAFA observatory of San Juan National University) was pointed to the IC250330A alert(IceCube GCN#  39943, trigger No 49427574, 20h 29m 18.48s, +10d 58m 33.6s, R=0.51deg) errorbox  91 sec after notice time (148 sec after trigger time) at 2025-03-30 08:33:34 UT, with upper limit up to  19.2m (Lipunov et al.GCN# 39942) MASTER cover map: https://master.sai.msu.ru/site/master2/observ.php?id=2828042 We analyzed MASTER archive images since 2010 of possible sources, that can be related with this event. There is blazar PKS 2032+107 inside 3 sigma https://vizier.cds.unistra.fr/viz-bin/VizieR?-source=&-out.add=_r&-out.add=_... We detected the blazar in a dim state with m=15.4m 4 minutes after the alarm, and 3 minutes later, it brightened to 14.6m. After it an hour later, blazar returned to its original state. MASTER archive light curve from 2010 year is available at http://observ.pereplet.ru/IC/MASTER_IC250330.jpg This, we report observation of an Zhirkov effect, discovered earlier (The Astrophysic Jornal Letters, 896, L19, 2020 https://ui.adsabs.harvard.edu/abs/2020ApJ...896L..19L/abstract ). View this GCN Circular online at https://gcn.nasa.gov/circulars/40042. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...