Angle-dependent hardening of the reprocessed spectra in ULXs powered by accretion onto neutron stars

Sricheta Karmakar, Alexander A. Mushtukov, Matthew Middleton

It is anticipated that mass accretion rates exceeding approximately $10^{19}\mathrm{g}{\mathrm{s}}^{-1}$ in X-ray pulsars lead to radiation-driven outflows from super-critical accretion disc…