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GCN Circular 25237

LIGO/Virgo S190728q: No counterpart candidates in H.E.S.S. observations
2019-07-31T20:28:00Z (5 years ago)
Fabian Schussler at CEA <>
M. de Naurois on behalf of the H.E.S.S. collaboration

The H.E.S.S. array of imaging atmospheric Cherenkov telescopes was used to carry out follow-up observations of the GW trigger S190728q (GCN #25187) using the LALInference map (GCN #25208).
Observations started July 28 at 20:17 UTC and lasted until July 29 02:45 UTC. A total of 7 pointings allowed to cover about 80% of the LALInference map provided in the Update-5 GCN notice and the GCN circular #25208. Observations of each of the pointings reached at least a 5-sigma sensitivity of about 20% of the flux from the Crab nebula. A preliminary analysis did not reveal significant gamma-ray emission in any of the observed fields. Further analyses of the data are on-going.

The following regions-of-interests were covered. Given is the start time of the first observation of each of the pointings and the center of the ROI. 

Time (UTC)		RA (J2000)	Dec (J2000)
2019-07-28 20:17	20h51m13s	7d01m49s
2019-07-28 21:12	20h52m22s	8d09m36s
2019-07-28 22:17	21h08m26s	15d01m03s
2019-07-28 22:59	20h57m32s	10d48m25s
2019-07-28 23:47	20h51m55s	5d40m45s
2019-07-29 00:16	21h14m46s	17d11m31s
2019-07-29 01:03	21h04m34s	12d56m30s

H.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, France, Germany, Ireland, Japan, the Netherlands, Poland, South Africa, Sweden, UK, and the host country, Namibia. For more details see
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