TITLE: GCN CIRCULAR NUMBER: 26578 SUBJECT: LIGO/Virgo S191205ah: MASTER OT detection DATE: 19/12/24 19:22:30 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, A.Chasovnikov, K.Zhirkov, A.Pozdnyakov, F.Balakin, T.Pogrosheva,D.Kuvshinov(Lomonosov Moscow State University, SAI, Physics Department), R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias), D. Buckley(South African Astronomical Observatory), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko, D.Kobtsev (Blagoveschensk Educational State University) During NS+BH LVC S191205ah (LVC GCN #26350, distance 385 +/- 164 Mpc) error-field inspection (Lipunov et al. GCN #26353, GCN 26379 https://master.sai.msu.ru/site/master2/ligo_1.php?id=10984 ) MASTER discovered PSN in the galaxy with unknown distance (AT2019xtt). MASTER OT J132500.30-295850.5 discovery - PSN in 0.2"W, 2"N of PGC722880 MASTER-IAC auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L ) discovered OT source at (RA, Dec) = 13h 25m 00.30s -29d 58m 50.5s on 2019-12-22 04:42:28.818 UT. The OT unfiltered automatic magnitude is 17.6m, mlim=19.7. The OT is seen in 6 images, including 2019-12-23 04:32:57U, 2019-12-24 04:36:39UT. T We have reference images without PSN on 2019-04-09 01:49:12UT with unfiltered mlim=19.9. Spectral observations are required.The distance for the galaxy is unknown. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/132500.30-295850.5.png The observation and reduction will continue. The message may be cited.