GRB 190829A: A long-lasting explosion offers surprises
June 2021 Gamma-ray bursts (GRBs) are bright X-ray and gamma-ray flashes observed in the sky, emitted by distant extragalactic sources. They are associated with the collapse of rapidly rotating massive stars, in which a…
Striking a Jet -and Pinpointing the Flame
February 2021 When striking a match – rubbing the flammable head [of the match] past a rough surface – it ignites in a flash and lights up. In very general terms something similar happens…
Dark matter in Irregular galaxy “WLM”
January 2021 For many decades now scientists have been searching for a new form of matter, which is believed to be ubiquitous in the Universe from cosmological to galactic scales. This invisible form of…
20th anniversary of H.E.S.S. groundbreaking
September 2020 The H.E.S.S. experiment is the biggest and longest-operating among all currently active facilities in ground-based gamma-ray astronomy, exploring the Very High Energy (VHE) radiation from the Universe. The collaboration that planned, built…
The kiloparsec-sized VHE gamma-ray emission of Centaurus A
July 2020 During the last decades the universe has been probed in the light of very high energy (VHE) gamma-rays, identifying many different kinds of Galactic sources, distant Quasars and other active galaxies. Curiously,…
ATOM: A trailer, a trigger and a tug for H.E.S.S.
May 2020 The H.E.S.S. array is a very advanced and efficient observatory for ground-based gamma-ray astronomy, sensitive enough to trace rapid variations in flaring sources on time-scales of minutes. Nonetheless, most gamma-ray sources require…
The many-faced quasar PKS 1510-089
January 2020 Among all classes of Active Galactic Nuclei (AGN), the so-called BL Lac objects had been prime candidates for Very High Energy (VHE) gamma-ray emission (Note 1) from the start, as they posses…
GRB 180720B The First Gamma-Ray Burst Detected in the Very-High-Energy Band
December 2019 After a decade-long search, the H.E.S.S. collaboration has succeeded to detected a gamma-ray burst in very-high-energy gamma light for the first time. This discovery was made in July 2018 using the huge…
A Gamma-ray view of Radio Galaxies
November 2019 The exploration of the universe at gamma-ray energies resulted in the discovery of ∼200 sources that emit photons of 1 Terra-Volt (1 000 000 000 000 eV) energy [1]. The largest group…
GW170817: Revisiting the site of a binary neutron star merger
October 2019 On August 17th 2017, the detection of the first electromagnetic counterpart to a gravitational-wave (GW) signal was achieved, originating from the binary neutron star (BNS) merger remnant. This result marked the start…