Accretion powered pulsars - Continuum spectra and light curves of settling accretion mounds

The polarimetric spectra expected from a mound of accreting plasma, settling subsonically onto the polar cap regions of an X-ray pulsar, were modeled using an analytical model of the accretion flow near the polar caps of the neutron stars. It is shown that, if the emission were to come from an exposed settling mound alone, with the relatively shallow temperature gradients appearing in the presently used model, the resulting spectra and light curves would not have the form observed in X-ray pulsars. More realistic models are being prepared, which show much steeper gradients and which may increase the number of low-frequency photons emergent from the mound.