TITLE: GCN CIRCULAR NUMBER: 39651 SUBJECT: IceCube-241224A: MASTER detection of PKS 1217+02 blazar flare with Zhirkov effect DATE: 25/03/10 12:01:17 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs 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, Yu.Tselik (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 Astrophysics Observatory) MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) started IceCube-241224A (IC GCN #38664, trigger No 303893, trigger time 07:10:04UT, 12h 20m 13.44s , +02d 46m 01.2s, R=0.74) errorbox 16 sec after notice time (178 sec after trigger time) at 2024-12-24 07:13:02 UT, with upper limit up to 19.6 mag (Lipunov et al.GCN#38663, MASTER cover map: https://master.sai.msu.ru/site/master2/event.php?id=2720792 ) We observed it in MASTER-SAAO, MASTER-OAFA and analyzed MASTER archive images since 2016 of the sources, that can be related with this event. There is quasar PKS 1217+02 inside 3-sigma IC error-box https://vizier.cds.unistra.fr/viz-bin/VizieR?-source=&-out.add=_r&-out.add=_RAJ%2C_DEJ&-sort=_r&-to=&-out.max=20&-meta.ucd=2&-meta.foot=1&-c=185.0495+2.0617222222222&-c.rs=5) We detected its brightening up to 15.7m near alert time. MASTER archive light curve from 2016 year is available at http://observ.pereplet.ru/IC/MASTER_IC241224A.jpg We report the observation of an Zhirkov effect, discovered earlier (The Astrophysic Jornal Letters, 896, L19, 2020 https://ui.adsabs.harvard.edu/abs/2020ApJ...896L..19L/abstract ).