{
  "bibcode": "2019GCN.24658....1T",
  "body": "D. Turpin (NAOC), N. Dagoneau (CEA/AIM), L.P. Xin (NAOC),\nX.H. Han (NAOC), J.Y. Wei (NAOC), C. Wu (NAOC),  L. Huang (NAOC),\nY. Xu (NAOC), H.B. Cai (NAOC), J. Wang (NAOC), X.M. Lu (NAOC),\nY.L. Qiu (NAOC), J.S. Deng (NAOC), L. Jia (NAOC), S.C. Zou (NAOC), \nS.F. Liu (NAOC), Q.C. Feng (NAOC), H.L. Li (NAOC), D.W. Xu (NAOC),\nY.J. Xiao (NAOC), W.L. Dong (NAOC), Y.T. Zheng (NAOC), P.P. Zhang (NAOC),\nR.S. Zhang (NAOC), E.W. Liang (GXU), X.G. Wang (GXU), Z.G. Dai (NJU),\nX.Y. Wang (NJU), Y.G. Yang (HBNU), J.R. Mao (YNAO), B. Cordier (CEA/AIM),\nS. Basa (CNRS/LAM), J.L. Atteia (UPS/IRAP), D. G�tz (CEA/AIM),\nA. Claret (CEA/AIM), N. Leroy (CNRS/LAL), C. Lachaud (CNRS/APC), \nE. Le Floc'h (CEA/AIM), S.N. Zhang (IHEP), B.B. Wu (IHEP),\nreport on behalf of the SVOM Ground Follow-up Group:\n\n\nWe observed 4 sky regions to cover the initial skymap of the \nLIGO/Virgo trigger S190521g (GCN24621), with the SVOM/GWAC-F30 \ntelescope operated by Huaibei Normal University and NAOC, CAS \nat Xinglong Observatory, China. \nThe SVOM/GWAC-F30 is equipped with Standard Johnson filters\nand 3Kx3K FLI CCD (FOV~1.8x1.8 degree). The GWAC-F30 is using\ntiling observation strategy. The tiles are calculated to cover\nthe most probable regions of the 90% localization area given in the\nGW probability skymap. Several images with a single exposure of 60s\ntime in R band are taken for each tile.\nThe 4 tile coordinates and the observation periods are listed below:\n\n# Ra[hms] Dec[dms] start-obs[UTC] Total_exp[s] N_image R_lim\n1 12:33:04.799 +28:03:00.00 2019-05-21T13:53:59.727 300.0 5 16.82\n2 16:40:40.800 +45:03:00.00 2019-05-21T14:02:19.437 300.0 5 16.33\n3 16:41:33.601 +46:45:00.00 2019-05-21T13:19:33.245 300.0 5 16.38\n4 16:50:12.239 +45:03:39.96 2019-05-21T13:16:11.066 420.0 7 15.75\n\nThe covering map is available at:\nhttp://cmm.svom.cn/gwpub/O3/S190521g/S190521g_GWAC-F30.png\n(user:svomo3 pwd:gwo3)\n\nThe first image was taken ~10.8 hours after the event trigger time. The\nweather conditions were partly cloudy during the night. \nNo credible new source is detected by our online pipeline.\nA more detailed image analysis is in progress with our offline pipeline\nto search for any fainter transient candidate.",
  "circularId": 24658,
  "createdOn": 1558698221000,
  "email": "dturpin-astro@hotmail.com",
  "subject": "LIGO/Virgo S190521g: No optical counterpart from SVOM/GWAC-F30 observations.",
  "submitter": "Damien Turpin at NAOC (CAS)  <dturpin-astro@hotmail.com>",
  "eventId": "LIGO/Virgo S190521g"
}