The origin of pulsating ultra-luminous X-ray sources: Low- and intermediate-mass X-ray binaries containing neutron star accretors

Understand

Ultra-luminous X-ray sources (ULXs) are those X-ray sources located away from the centre of their host galaxy with luminosities exceeding the Eddington limit of a stellar-mass black hole ($L_X>10^{39}\;{\rm erg\,s}^{-1}$).

• The discovery of X-ray pulsations in some of these objects (e.g.
• M82~X-2) suggests that a certain fraction of the ULX population may have a neutron star accretor.
• We present systematic modelling of low- and intermediate-mass X-ray binaries (LMXBs and IMXBs; donor-star mass range $0.92$--$8.0$~M$_{\odot}$ and neutron-star accretors) to explain the formation of this sub-population of ULXs.