Blazars in hard X-rays

TL;DR

This paper discusses the significance of hard X-ray observations of blazars, especially those with extreme jet powers, to understand their emission mechanisms and potential for study with the Simbol-X mission.

Contribution

It highlights the importance of hard X-ray observations of specific blazar subclasses with extreme jet powers, proposing their suitability for future study with Simbol-X.

Findings

Blazars with small jet powers emit synchrotron peaks at tens of keV.

Powerful jet blazars have high-energy peaks below the MeV band.

Hard X-ray observations can reveal key properties of extreme blazar subclasses.

Abstract

Although blazars are thought to emit most of their luminosity in the gamma-ray band, there are subclasses of them very prominent in hard X-rays. These are the best candidates to be studied by Simbol-X. They are at the extremes of the blazar sequence, having very small or very high jet powers. The former are the class of TeV emitting BL Lacs, whose synchrotron emission often peaks at tens of keV or more. The latter are the blazars with the most powerful jets and have high black hole masses accreting at high (i.e. close to Eddington) rates. These sources are predicted to have their high energy peak even below the MeV band, and therefore are very promising candidates to be studied with Simbol-X.