CAOSP abstracts, Volume: 48, No.: 3, year: 2018

Abstract: Monitors of X-ray emission are important instruments for observing the long-term activity of cosmic sources on the long timescales (e.g. years). We show the perspectives and possibilities of observing the selected types of X-ray binary sources with the planned satellites THESEUS and eXTP. The hardness of the X-ray spectrum largely determines the observability of a given object (or a type of objects) with a monitor operating in the specific band. We show the perspectives of detecting and observing outbursts in the soft X-ray transients with the hard X-ray monitors eXTP/WFM and THESEUS/XGIS. Their broad energy bands and energy resolution will enable to detect the outbursts and the complex spectral changes during these events. We also show the perspectives of observing the binary supersoft X-ray sources with the planned THESEUS/SXI. These sources sometimes have the luminosity close to the Eddington limit but their X-ray emission is usually below the band used by the monitors.