Overview of non-transient gamma-ray binaries and prospects for the Cherenkov Telescope Array

TL;DR

This paper assesses the Cherenkov Telescope Array's potential to study non-transient gamma-ray binaries, focusing on spectral measurement capabilities and variability detection on short time scales.

Contribution

It demonstrates CTA's ability to analyze spectral evolution and variability of gamma-ray binaries with unprecedented sensitivity and temporal resolution.

Findings

CTA can measure spectral parameters on 30-minute time scales.

CTA's sensitivity enables detailed spectral evolution studies.

High-accuracy measurements can address source-specific questions.

Abstract

We simulate the spectral behaviour of the non-transient gamma-ray binaries using archival observations as a reference. With this we test the CTA capability to measure the sources' spectral parameters and detect variability on various time scales. We review the known properties of gamma-ray binaries and the theoretical models that have been used to describe their spectral and timing characteristics. We show that CTA is capable of studying these sources on time scales comparable to their characteristic variability time scales. For most of the binaries, the unprecedented sensitivity of CTA will allow the spectral evolution to be studied on a time scale as short as 30 min. This will enable a direct comparison of the TeV and lower energy (radio to GeV) properties of these sources from simultaneous observations. We also review the source-specific questions that can be addressed with such high-accuracy CTA measurements.