Study of high-energy emission from high mass X-ray binaries

Since their discovery, the study of High Mass X-ray Binaries (HMXBs) has revealed an extremely powerful and energetic environment that is capable of accelerating particles to Very High Energies (VHE). With the advent of more advanced gamma-ray astronomy technology in the last decade a small number of HMXBs have been detected at GeV and TeV energies which has led to the classification of gamma-ray binary systems. One of these systems, PSR B1259-63, has been intensively studied in the past decade to understand the origins of the off-set GeV flaring during orbital periastron. An analysis I have conducted of Fermi-LAT observations of the 2017 passage, along with comparison to previous observations, has led to new insight of the GeV flare origin where the energy is released from unshocked and weakly shocked electrons of the pulsar wind as a beaming effect in the direction of the observer. With current X-ray telescopes, resolving the multiple X-ray emission sources and high variability of HMXBs requires extremely long observations and even then, may not be resolvable. The Athena X-ray Integral Field Unit (X-IFU), currently in development, will be capable of significantly higher resolution observations on both the energy and time scale. Vela X-1 is an archetypical HMXB where the spectra exhibit many emission lines that vary during the orbital eclipse of the binary companion. X-IFU will have the ability to detect changes in the emission line profile and possibly discover new emission lines. I have simulated X-IFU observations of Vela X-1 with theoretical line profiles modelled with XSTAR. The Cherenkov Telescope Array (CTA) will provide an order of magnitude greater sensitivity of the TeV observations of HMXBs. In my work I have studied the capability of CTA to detect variability from microquasars depending on their fluxes and observation exposure