H.E.S.S. observations of the flaring gravitationally lensed galaxy PKS 1830-211
Abstract
PKS 1830-211 is a known macrolensed quasar located at a redshift of z = 2.5. Its high-energy gamma-ray emission has been detected with the Fermi-Large Area Telescope (LAT) instrument and evidence for lensing was obtained by several authors from its high-energy data. Observations of PKS 1830-211 were taken with the High Energy Stereoscopic System (H.E.S.S.) array of Imaging Atmospheric Cherenkov Telescopes in 2014 August, following a flare alert by the Fermi-LAT Collaboration. The H.E.S.S observations were aimed at detecting a gamma-ray flare delayed by 20-27 d from the alert flare, as expected from observations at other wavelengths. More than 12 h of good-quality data were taken with an analysis threshold of ∼67 GeV. The significance of a potential signal is computed as a function of the date and the average significance over the whole period. Data are compared to simultaneous observations by Fermi-LAT. No photon excess or significant signal is detected. An upper limit on PKS 1830-211 flux above 67 GeV is computed and compared to the extrapolation of the Fermi-LAT flare spectrum.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- July 2019
- DOI:
- 10.1093/mnras/stz1031
- arXiv:
- arXiv:1904.05139
- Bibcode:
- 2019MNRAS.486.3886H
- Keywords:
-
- gravitational lensing: strong;
- diffuse radiation;
- gamma-rays: galaxies;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- Accepted for publication in MNRAS