{
  "bibcode": "2014GCN.16307....1G",
  "body": "E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, A.Belinski, N.Tyurina, \nN.Shatskiy, P.Balanutsa, D.Zimnukhov, A.Kuznetsov, V.V.Chazov, D.Denisenko, \nA.Sankovich\nLomonosov Moscow State University,\nSternberg Astronomical Institute, Moscow State University\n\nA. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik\nKislovodsk Solar Station of the Pulkovo Observatory\n\nV.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov\nBlagoveschensk Educational State University, Blagoveschensk\n\nK.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk\nIrkutsk State University\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 II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) \nlocated in  Tunka  began observations of   GRB140512A  (Pagani et. al. GCN \n16249) from  pointing  on several FERMI alerts.\nDuring the second set of observations by FERMI coordinates the GRB140512A \nerror box was covered by our  very wide field cameras MASTER VWF \n(FOV=2x384 square degrees, D=72mm, f/1.2, 1 pix = 22 arcsec) which \ninstalled on  MASTER-II telescope. So we have 5 images with 5 second \nexptime without time gap since 2014-05-12 19:32:38 i.e. 29 sec. after the \ntrigger and 49 sec. after the burst. We did not see optical transient \n(Pagani et. al. GCN 16249)  at GRB140512A place. The  5-sigma upper limit \non coadd of 5 MASTER-VWF images since 49 sec. till 74 sec. after the burst \nhas been about 12.3 mag. The prompt images available here \nhttp://master.sai.msu.ru/static/GRB/GRB140512A.png .\n\nAfter several repointing by FERMI alerts MASTER II was pointed to the \nGRB140512A 171 sec after trigger time at 2014-05-12 19:34:40.212 UT in two \npolarizations by Swift coordinates. We definitely see OT on our images in \nboth polarizations.\n\nOut final light curve  is  available in Tab. 1\n\n        Start time       Exptime T-T_mid     P/      eP/      P\\    eP\\\n2014-05-12T19:34:40.212     30     186    14,45    0,04    14,37  0,03\n2014-05-12T19:36:37.643     60     318    14,72    0,05    14,74  0,04\n2014-05-12T19:38:24.484     60     425    15,60    0,12    15,35  0,06\n2014-05-12T19:39:47.447     60     508    15,41    0,10    15,65  0,07\n2014-05-12T19:41:10.651     60     591    15,75    0,13    15,75  0,08\n2014-05-12T19:42:32.663     60     673    15,98    0,16    15,94  0,09\n2014-05-12T19:43:54.083     60     754    16,46    0,22    16,42  0,12\n2014-05-12T19:45:56.002    170     931    16,37    0,20    16,79  0,15\n2014-05-12T19:50:30.564    180    1211    17,50    0,39    16,84  0,15\n2014-05-12T19:56:11.667    180    1552    16,82    0,27    17,57  0,22\n\nP/ and P\\ is a polarization filter which are oriented at an angle 45 and \n135 degrees to RA axis respectivel.  eP/ and eP\\ is a error of P/ and P\\ \nvalues.  T is a  GRB trigger time.\n\nThe dimensionless Stokes parameter averaged over 5 first expositions is \nestimated to be less than observational error which equals to 2.9% (i.e. q \n= 0.3 +- 2.9%). So big error is connected to observation in a morning \ntwilight (sun altitude ~ 12 d) and high object zenith distance (z ~ 70 d).\n\nOur  unfiltered magnitude is well described by a parity 0.8R + 0.2B  (USNO-B1)\n\nThe message may be cited.",
  "circularId": 16307,
  "createdOn": 1400478471000,
  "email": "gcncirc@observ.inetcomm.ru",
  "subject": "GRB 140512A: MASTER prompt and afterglow optical observations",
  "submitter": "Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc@observ.inetcomm.ru>",
  "eventId": "GRB 140512A"
}