The majority of the active galactic nuclei detected at very-high-energies above 100 GeV belong to the class of blazars with a small angle between the jet-axis and the line-of-sight. Only about 10 percent of the gamma-ray AGN are objects with a larger viewing angle resulting in a smaller Doppler boosting of the emission. Originally, it was believed that gamma-ray emission can only be observed from blazars and those are variable in its brightness. Instead, the last years have shown that non-blazar active galaxies also show a fascinating variability behaviour which provide important new insights into the physical processes responsible for the gamma-ray production and especially for flaring events.
Here, we report on the observation of gamma-ray variability of the active galaxy PKS 0625-354 detected with the H.E.S.S. telescopes in November 2018. The classification of PKS 0625-354 is a still matter of debate. The H.E.S.S. measurements were performed as part of a flux monitoring program and showed in the first night of the observation a detection of the object within one observation run of 30 minutes. A denser observation campaign followed for the next nine nights resulting in a decrease of the gamma-ray flux. Those observations were accompanied with Swift and ATOM measurements in the X-ray and UV/optical band allowing for the reconstruction of the first simultaneous broad-band spectral energy distribution. We will discuss the implications of the gamma-ray variability of the object as well as the spectral energy distribution.
AGN; Gamma rays; radio galaxy, multi-wavelength emission