Radiation from condensed surface of magnetic neutron stars

Recent observations show that thermal X-ray spectra of many isolated neutron stars are featureless and in some cases well fit by a blackbody. Such perfect blackbody spectra are puzzling as radiative transport through typical neutron star atmospheres causes noticeable deviation from blackbody. Previous studies have shown that in a strong magnetic field, the outermost layer of the neutron star may be in a condensed solid or liquid form because of the enhanced cohesive energy of the condensed matter. Thus, thermal radiation can emerge directly from the degenerate metallic condensed surface, without going through a gaseous atmosphere. Here we discuss emission properties of condensed Fe and H surfaces of magnetic neutron stars in the regimes where such condensation may be possible.