What can Simbol-X do for gamma-ray binaries?

TL;DR

Simbol-X, with its high sensitivity in hard X-rays, will significantly advance the study of gamma-ray binaries by constraining models, confirming persistent emission, and aiding in discovering new systems, complementing Fermi observations.

Contribution

This paper discusses how Simbol-X will improve understanding of gamma-ray binaries through enhanced spectral measurements and potential discovery of new systems.

Findings

Simbol-X will constrain models of gamma-ray binaries.

Persistent hard X-ray emission will be detectable beyond 10 keV.

Simbol-X will aid in discovering new gamma-ray binaries.

Abstract

Gamma-ray binaries have been uncovered as a new class of Galactic objects in the very high energy sky (> 100 GeV). The three systems known today have hard X-ray spectra (photon index ~ 1.5), extended radio emission and a high luminosity in gamma-rays. Recent monitoring campaigns of LSI +61 303 in X-rays have confirmed variability in these systems and revealed a spectral hardening with increasing flux. In a generic one-zone leptonic model, the cooling of relativistic electrons accounts for the main spectral and temporal features observed at high energy. Persistent hard X-ray emission is expected to extend well beyond 10 keV. We explain how Simbol-X will constrain the existing models in connection with Fermi Space Telescope measurements. Because of its unprecedented sensitivity in hard X-rays, Simbol-X will also play a role in the discovery of new gamma-ray binaries, giving new insights into the evolution of compact binaries.