Detection of new Extreme BL Lac objects with H.E.S.S. and Swift XRT

TL;DR

This paper reports the detection of new extreme high synchrotron peaked blazars at TeV energies using H.E.S.S. and Swift XRT, providing insights into particle acceleration and radiation mechanisms in these powerful cosmic accelerators.

Contribution

It presents new TeV detections of EHBLs at redshifts below 0.2 and combines X-ray observations to study their emission processes, expanding the known sample of such objects.

Findings

New EHBLs detected at TeV energies with H.E.S.S.

X-ray observations with Swift XRT support emission mechanism analysis.

Enhanced understanding of particle acceleration in EHBLs.

Abstract

Extreme high synchrotron peaked blazars (EHBLs) are amongst the most powerful accelerators found in nature. Usually the synchrotron peak frequency of an EHBL is above $10^{17}\,$Hz, i.e., lies in the range of medium to hard X-rays making them ideal sources to study particle acceleration and radiative processes. EHBL objects are commonly observed at energies beyond several TeV, making them also powerful probes of gamma-ray absorption in the intergalactic medium. During the last decade, several attempts have been made to increase the number of EHBL detected at TeV energies and probe their spectral characteristics. Here we report new detections of EHBLs in the TeV energy regime, each at a redshift of less than 0.2, by the High Energy Stereoscopic System (H.E.S.S.). Also, we report on X-ray observations of these EHBLs candidates with Swift XRT. In conjunction with the very high energy observations, this allows us to probe the radiation mechanisms and the underlying particle acceleration processes.