Mkn 180 BL Lac Type Object Viewed at High and Very-High Energies

Abstract

Blazars are among the most powerful objects in the Universe, whose photon spectrum extends from radio to very high energy gamma-rays (γ-rays). Spectral energy distribution (SED) of blazars has a two-humped shape, whose low-energy part originates from the leptonic mechanism of synchrotron radiation of relativistic electrons in the blazars' jets. It is generally believed that the high-energy part of the spectral energy distribution is of hadronic and leptonic scenarios, but different localization of the source of emission within the core region or far beyond is considered. Also, blazars' emission is characterized by rapid variability at all wavelengths. The tracking of the flaring events at the radio band to connected ones at higher energies may allow localizing emission regions. High-frequency peaked Bl Lacertae type of blazar objects (HBL) are characterized by multi-wavelength variability and SED peaking at the GeV–TeV energy range. Thus, HBL objects have been considered as the best candidate for the sources of very high γ-rays. Mkn 180 is the HBL object with the spectrum that has been measured through radio and X-ray bands to high energy γ-rays. The study of the connection between the outbursts from Mkn 180 viewed from radio to very high energy γ-rays is presented together with its features at the MeV–TeV energy range. These results can help find the parameters for the models of generation of high-energy γ-ray emission in Bl Lac-type objects.