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Aims. Despite recent progress in the field, there are still many open questions regarding γ-ray binaries. In this paper we provide an overview of non-transient γ-ray binaries and discuss how observations with the Cherenkov Telescope Array (CTA) will contribute to their study. Methods. We simulated the spectral behaviour of the non-transient γ-ray binaries using archival observations as a reference. With this we tested the CTA capability to measure the spectral parameters of the sources and detect variability on various timescales. Results. We review the known properties of γ-ray binaries and the theoretical models that have been used to describe their spectral and timing characteristics. We show that the CTA is capable of studying these sources on timescales comparable to their characteristic variability timescales. For most of the binaries, the unprecedented sensitivity of the CTA will allow studying the spectral evolution on a timescale 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 these high-accuracy CTA measurements. [ABSTRACT FROM AUTHOR]

Context. HD 195592 is an O-type super-giant star, known as a well-established runaway. Recently, a Fermi γ-ray source (2FGL J2030.7+4417) with a position compatible with that of HD 195592 has been reported. Aims. Our goal is to explore the scenario where HD 195592 is the counterpart of the Fermi γ-ray source, modeling the non-thermal emission produced in the bowshock of the runaway star. Methods. We calculated the spectral energy distribution of the radiation produced in the bowshock of HD 195592 and we compared it with Fermi observations of the 2FGL J2030.7+4417. Results. We present relativistic particle losses and the resulting radiation of the bowshock of HD 195592 and show that the latter is compatible with the detected γ-ray emission. Conclusions. We conclude that the Fermi source 2FGL J2030.7+4417 might be produced, under some energetic assumptions, by inverse Compton up-scattering of photons from the heated dust in the bowshock of the runaway star. Therefore, HD 195592 might be the very first object detected belonging to the category of γ-ray emitting runaway massive stars, whose existence has been recently predicted. [ABSTRACT FROM AUTHOR]

Context. Conceptually reconstructing the physical conditions in relativistic jets, given the observed electromagnetic spectrum, is a complex inverse problem. Aims. We aim to improve our understanding of the mechanisms operating in relativistic jets by modeling their broadband electromagnetic spectrum. Methods. We develop an inhomogeneous jet model where the injection of relativistic primary and secondary particles takes place in a spatially extended region. We calculate the contribution of all particles species to the jet emissivity by several radiative processes, and assess the effect of gamma-ray absorption in internal and external photon fields. A number of specific models with different parameters are computed to explore the possibilities of this scenario. Results. We obtain a variety of spectral shapes depending on the model parameters, some of them predicting significant gamma-ray emission. The observed broadband spectrum of the low-mass microquasar XTE J1118+480 can be satisfactorily reproduced by the model. Conclusions. Our results indicate that outbursts similar to those displayed in the past by XTE J1118+480 might be detected with present-day gamma-ray instruments. [ABSTRACT FROM AUTHOR]