MAGIC eyes to the extreme: testing the blazar emission models on EHBLs

TL;DR

This paper reports on multi-wavelength observations of extreme high-energy peaked BL Lac objects, focusing on 1ES 1426+426, and evaluates various emission models to explain their broadband spectra, highlighting challenges to standard models.

Contribution

It presents the first detection of VHE gamma rays from four EHBLs by MAGIC and compares different emission models for their spectral energy distributions.

Findings

Detection of VHE gamma rays from four EHBLs.

Challenges to standard one-zone synchrotron self-Compton models.

Evaluation of alternative emission models like spine-layer and hadronic.

Abstract

Extreme high-energy peaked BL Lac objects (EHBLs) are blazars whose synchrotron emission peaks at exceptionally high energies, above few keV, in the hard X-ray regime. So far, only a handful of those objects has been detected at very high energy (VHE, E > 100 GeV) gamma rays by Imaging Atmospheric Cherenkov Telescopes. Very remarkably, VHE observations of some of these blazars (like 1ES 0229+200) have provided evidence of a VHE gamma-ray emission extending to several TeV, which is difficult to explain with standard, one-zone synchrotron self-Compton models usually applied to BL Lac objects. The MAGIC collaboration coordinated a multi-year, multi-wavelength observational campaign on ten targets. The MAGIC telescopes detected VHE gamma rays from four EHBLs. In this paper we focus on the source 1ES 1426+426 and its X-ray and VHE gamma-ray properties. The results of different models (synchrotron self-Compton, spine-layer, hadronic) reproducing the broadband spectral energy distribution are also presented.