H.E.S.S. upper limits on VHE gamma emission from AT2018cow
ATel #11956; Mathieu de Naurois for the H. E. S. S. collaboration
on 15 Aug 2018; 18:21 UT
Credential Certification: Andrew Taylor (andrew.taylor@desy.de)
Subjects: TeV, VHE, Gamma-Ray Burst, Supernovae, Transient
The H.E.S.S. array of imaging atmospheric Cherenkov telescopes was used to carry
out follow-up observations of AT2018cow (ATel #11727) between the 3rd and 5th
July 2018, for a total of 2.4 hours. H.E.S.S. observed the region around the source
position (RA, Dec) = (244.00, 22.27) from ATel #11727.
Preliminary off-site calibration and analysis with the data taken by the CT5 telescope
(CT5 mono), searching for a point-like gamma-ray source from the source target, revealed
no significant detection. These observations allowed us to place preliminary
upper limits on the integrated flux (assuming a spectral index value of -2) from the source target:
above the energy threshold 220 GeV (with a 95% confidence limit) an upper limit of 5e-12 ph cm^-2 s^-1; above 1 TeV (with a 95% confidence limit) an upper limit of 5e-13 ph cm^-2 s^-1.
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, the Czech Republic, France, Germany, Ireland, Netherlands, Japan, Poland,
South Africa, Sweden, UK, and the host country, Namibia.
