Pulsars, transients and relativistic astrophysics

Abstract:

We describe the scientific potential of a Soft X-ray Imager (SXI) onboard the ESA–CAS satellite SMILE to study the activity of cosmic X-ray sources in the soft X-ray region and located in the fields planned to be observed by SXI. We used the 2–3 keV band flux of the monitor MAXI/ISS, covering at least part of the expected band of the SXI/SMILE telescope. We discuss how SXI can contribute to this branch and how combining the SXI/SMILE data with those obtained by other satellites on the same days can be helpful if the light curves of the 1-day means are used. We show these possibilities on several examples of cosmic X-ray sources (Vela X-1 and GROJ1008-57 containing neutron stars accreting matter from their companions) in the field of view of SXI. Including observations from MAXI/ISS and BAT/Swift will enable extending the coverage to the energy of 50 keV

Abstract:

AbstractX-ray polarimetry has long been considered the ‘holy grail’ of X-ray astronomy. Fortunately, after a silence of more than 40 years, the field is now rejuvenating. In fact, an X-ray polarimeter onboard a Cube-sat nano-satellite has been recently successfully operated. IXPE, the Imaging X-ray Polarimetry Explorer, will be launched in 2021 while eXTP, containing a larger version of IXPE, is expected to be launched in 2027. Although at present it is difficult to predict the discoveries that, given their exploratory nature, IXPE and eXTP will obtain, the path for a follow-up mission can already be envisaged. In this paper we describe the scientific goals of such a follow-up mission, and present a medium-size mission profile that can accomplish this task.