{
  "bibcode": "2015GCN.17838....1G",
  "body": "E. Gorbovskoy, V. Lipunov,  N.Tyurina, V.Kornilov, P.Balanutsa, \nA.Kuznetsov,D.Kuvshinov,\nLomonosov Moscow State University, Sternberg Astronomical Institute\n\nD.Buckley, S. Potter, A.Kniazev, M.Kotze\nSouth African Astronomical Observatory\n\nA. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik\nKislovodsk Solar Station of the Pulkovo Observatory\n\nK.Ivanov, O.Gres, N.M.Budnev, S.Yazev, O.Chuvalaev, \nV.A.Poleshchuk\nIrkutsk State University\n\nV.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov, A.Gabovich\nBlagoveschensk Educational State University, Blagoveschensk\n\nV.Krushinski, I.Zalozhnih,  A. Popov\nUral Federal University, Kourovka\n\nHugo Levato and Carlos Saffe\nInstituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)\n\nClaudio Mallamaci, Carlos Lopez and Federico Podest\nObservatorio Astronomico Felix Aguilar (OAFA)\n\nMASTER-Kislovodsk  robotic telescope (MASTER-Net: http://observ.pereplet.ru, \nFOV = 2x2 square degrees in paralel mode ( Lipunov et al., 2010, MASTER \nRobotic Net, Advances in Astronomy, vol. 2010, pp. 1-7)) located in \nKislovodsk was pointed to the  MAXI/GSC GRB150518A \n(Kawamuro et al., GCN 17825) 21 sec after notice time and 3189 sec after \ntrigger time at 2015-05-18 22:35:43 UT. On our first (180s exposure) \nimage we do not  found OTs within Swift/XRT  erro-box  (Sbarufatti et al., \nGCN 17827)  brighter then 18.5 .\n\nBut we see bright object at positon:  15h 36m 53.67s , +16d 19m  36s.5\nwith 17.5  unfiltered mag  outside XRT and inside MAXI.\n\n\nMASTER-SAAO  robotic telescope (MASTER-Net: http://observ.pereplet.ru,\nFOV = 2x2 square degrees in paralel mode ( Lipunov et al., 2010, MASTER\nRobotic Net, Advances in Astronomy, vol. 2010, pp. 1-7)) located in\nSouht Africa Astronomical Observatory was pointed to the  MAXI/GSC \nGRB150518A\n(Kawamuro et al., GCN 17825) 13 sec after notice time and 3189 sec after\ntrigger time at 2015-05-18 22:35:35 UT. On our first (180s exposure)\nimage we not  found OTs within Swift/XRT error-box (Sbarufatti et al., \nGCN 17827)  brighter then\n17.1 .\n\nBut we see bright object at positon:  15h 36m 51.70s , +16d 19m  13s.6\nwith ~ 17.0  unfiltered mag  outside Swift/XRT and inside MAXI.\n\n  There is one asteroid MPC 2010 KL61 with poorly\nastrometrical efemerids (Leave for survey recovery) at MPC Data Base.\nThe offset both Russian and South Africa OT positiion 36 arc sec. This \ncorresponds to parallax effect for Solar System Body.\n\nWe do not see any OT at the aftergow canditate position (Xu et al.,\nGCNC 17829, 17832; Mao et al., GCNC 17830; Littlejohns et al., GCNC 17831;\nMoskvitin GCN 17834) with same limit (3 sigma).\n\nWe have only one alert image in each telescope because MASTER telescope \nrecieved new MAXI correction of the error box and X-ray Transient leave \nthe MASTER FOV during alert observations.\n\nBut we have observation this X-ray aftergrow position before last \ntrigger activated by previouse Fermi (trigger number 451674501, 25 apr \n2015) and during regular synoptic survey (MASTER-Tunka,  ~ 2 days after \ntrigger).\n\nPreliminary results:\n\nId     Pro.type\t   Date        time    Exp.time\tLimit\tFilt.\tSite\n                               Starting         (3sigma)\n\n759597  SumSurvey 2015-05-20  17:02:11\t480\t20.1\tW\tTunka\n1458076 MaxiAlert 2015-05-18  22:35:35 \t180 \t17.1 \tP/ \tSAAO\n1458345\tMaxiAlert 2015-05-18  22:35:43\t180\t18.5\tP|   Kislovodsk\n823020  FermiInsp 2015-04-25  20:11:41 \t180 \t19.9 \tW    Kislovodsk\n\nWhere W - unfiltered, P - polarization unfiltered. All magnitude \ncalculated with respect to hundrends USNO B stars  with calibration:\n  m = 0.2B + 0.8R .\n\n\nAt the Tunka Survey we see marginaly faint (~2 sigma) object on the X-ray \nposition (Sbarufatti et al., GCN 17827). But this is may be noice. We have \na lot of images in MASTER NET Data Base imaging last \nseveral years with   Swift XRT error box. No object we see on this place \nwith 20.5 mag limit on first overview (since 2010).\n\nThe message may be cited.",
  "circularId": 17838,
  "createdOn": 1432213761000,
  "email": "lipunov@xray.sai.msu.ru",
  "subject": "GRB 150518A: MASTER-net before, early and after  optical stereoscopic observations with possible MP discovery inside MAXI error box",
  "submitter": "Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>",
  "eventId": "GRB 150518A"
}