{
  "bibcode": "2021GCN.29339....1L",
  "body": "V. Lipunov, V.Kornilov, E.Gorbovskoy,N.Tiurina,P.Balanutsa,F.Balakin, V.Vladimirov, A.Kuznetsov,K.Zhirkov,D. Vlasenko, I.Gorbunov, D.Zimnukhov, \nV.Senik, A.Chasovnikov,A.Pozdnyakov,V.Topolev, D.Cheryasov(Lomonosov Moscow State University, SAI, Physics Department),\nR. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico FelixAguilar OAFA),\nR. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias),\nD. Buckley (South African Astronomical Observatory),\nO.A. Gres, N.M. Budnev (Irkutsk State University, API),\nA. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),\nA. Gabovich, V.Yurkov, Yu. Sergienko (Blagoveschensk Educational StateUniversity)\n\nMASTER-OAFA robotic telescope (MASTER-Net: http://observ.pereplet.ru  Lipunov et al.,2010,Advances in Astronomy,2010,30L)\nautomatically was pointed (Lipunov et al. GCN 29336)\nto Fermi GRB210120A (Ttrigger=07:10:44UT, Fermi GCN 29334, BALROG localization Biltzinger et al. GCN 29335,\nBarthelmy https://gcn.gsfc.nasa.gov/other/210120A.gcn3 )\n80s after notice time (143s after trigger time) at 2021-01-20 07:13:07UT\n\nAt first images MASTER auto-detection system found fast changing optical transient\n  MASTER OT J105242.66+152355.0 / AT2021axc\nat (RA, Dec) = 10h 52m 42.66s +15d 23m 55.0s at 2021-01-20 07:20:30UT\nwith unfiltered m_OT=18.6 at the beginning stage.\n\nThe OT is seen at several images. There is no any sources at this place in \nMASTER database since 2004.\n\nThe nearest source in VIZIER is SDSS galaxy in 4.9\" with rmag(as most \nclosest to MASTER unfiltered)=22.217 (22.088 in PanSTARRS)\n\nThe reduction will be continued.\nThis message may be cited.",
  "circularId": 29339,
  "createdOn": 1611175289000,
  "email": "lipunov@xray.sai.msu.ru",
  "subject": "GRB 210120A: MASTER OT (possibly) discovery",
  "submitter": "Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>",
  "eventId": "GRB 210120A"
}