Speaker
Description
Gamma-ray binaries are high-mass systems characterized by spectral energy distributions that peak near 100 MeV. X-ray observations of these systems reveal no detected spectral lines; only upper limits on Fe Kα are reported. This line deficit may be intrinsic, originating from extreme plasma ionization, or pulsar-driven disruption of the circumstellar environment. From an instrumental perspective, however, current observatories may lack both the sensitivity to recover weak lines and the phase coverage to detect phase-dependent emission. NewAthena offers the opportunity to resolve this issue with its state-of-the-art high-resolution spectroscopy instrument.
The pulsar wind interaction with the disk near periastron is expected to increase plasma temperature, density, and ionization to levels potentially sufficient for line emission. Whether or not lines are detected, orbit-resolved simulations constrain the disk parameters, confirming physical conditions if lines are recovered, or placing upper limits on disk parameters if they are not.
To model this phase-dependent behaviour, we simulated orbit-resolved synthetic spectra via SIXTE in preparation for NewAthena observations. In this talk, we will present detection limits on weak spectral features, constraints on disk parameters under which line emission arises, and synthetic spectra across orbital phases.
