{
  "bibcode": "2017GCN.21673....1D",
  "body": "M. de Naurois on behalf of the H.E.S.S. collaboration\n\nThe H.E.S.S. array of imaging atmospheric Cherenkov telescopes [1] was used to carry out follow-up observations of the GW trigger G297595 (GCN #21474) using the LALInference map (GCN #21493).\nObservations started August 17 at 00:10 UTC and a total of 11 pointings were obtained over three consecutive nights. Each of the observations has a sensitivity of about 20% of the flux from the Crab nebula at 5 sigma. The observations cover about 80% of the LALInference localisation probability. A preliminary analysis with an energy threshold of about 500GeV did not reveal significant gamma-ray emission in any of the observed fields (within a field-of-view of ~2.5deg radius around the coordinates given below). Further analyses of the data are on-going.\n\nThe following regions-of-interests were observed. Given is the start time in UTC for each of the typically 28min long observations and the center of the ROI. \n\n     Time (UTC)              RA                  Dec\n2017-08-17 00:10     2h38m19s     -48d43m12s\n2017-08-17 00:40     3h03m07s     -45d35m24s\n2017-08-18 00:10     2h36m58s     -51d15m59s \n2017-08-18 00:40     3h05m57s     -42d45m49s \n2017-08-18 01:10     3h13m53s     -39d46m14s   \n2017-08-18 23:55     2h34m20s     -46d11m42s\n2017-08-19 00:25     2h59m24s     -48d23m28s\n2017-08-19 00:55     3h16m57s     -37d07m49s\n2017-08-19 01:25     2h49m10s     -46d15m52s\n2017-08-19 01:55     3h18m53s     -34d30m06s\n2017-08-19 02:25     3h19m28s     -42d22m29s\n\nH.E.S.S. is an array of five imaging atmospheric Cherenkov telescopes for the detection of very-high-energy gamma-ray sources and is located in the Khomas Highlands in Namibia. It was constructed and is operated by researchers from Armenia, Australia, Austria, the Czech Republic, France, Germany, Ireland, Netherlands, Japan, Poland, South Africa, Sweden, UK, and the host country, Namibia. For more details see https://www.mpi-hd.mpg.de/hfm/HESS/",
  "circularId": 21673,
  "createdOn": 1503570301000,
  "email": "fabian.schussler@cea.fr",
  "subject": "LIGO/Virgo G297595: H.E.S.S. very-high energy gamma-ray follow-up",
  "submitter": "Fabian Schussler at HESS Observatory  <fabian.schussler@cea.fr>",
  "eventId": "LIGO/Virgo G297595"
}