//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26512 SUBJECT: LIGO/Virgo S191220af: Global MASTER-Net observations report DATE: 19/12/20 12:48:06 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov, D. Cheryasov (Lomonosov Moscow State University, SAI, Physics Department), 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), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), 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 (Blagoveschensk Educational State University) MASTER-Amur robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Blagoveshchensk State Pedagogical University) started inspect of the LIGO/Virgo S191220af errorbox 761 sec after notice time and 1023 sec after trigger time at 2019-12-20 12:41:17 UT, with upper limit up to 17.2 mag. The observations began at zenith distance = 24 deg. The sun altitude is -48.1 deg. The galactic latitude b = 60 deg., longitude l = 61 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/ligo_1.php?id=11083 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 1053 | 2019-12-20 12:41:17 | MASTER-Amur | (04h 38m 46.14s , +71d 00m 59.7s) | C | 60 | 17.2 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26513 SUBJECT: LIGO/Virgo S191220af: Retraction of GW compact binary merger candidate DATE: 19/12/20 12:59:21 GMT FROM: Nelson Christensen at Obs.de la Cote dAzur,Nice The LIGO Scientific Collaboration and the Virgo Collaboration report: The trigger S191220af is no longer considered to be a candidate of Interest due to severe nonstationarity in L1 data.