The optical/UV excess of isolated neutron stars in the RCS model

TL;DR

This paper investigates the optical/UV excess observed in isolated neutron stars and demonstrates that the resonant cyclotron scattering (RCS) model can explain most of these excesses, with additional bremsstrahlung contribution in some cases.

Contribution

The study applies the RCS model to explain the optical/UV excess in XDINSs and discusses the role of bremsstrahlung emission for specific sources.

Findings

RCS model accounts for optical/UV excess in most XDINSs

Bremsstrahlung emission may contribute to the spectrum of RX J2143.0+0654

The model explains spectral features consistent with observations

Abstract

The X-ray dim isolated neutron stars (XDINSs) are peculiar pulsar-like objects, characterized by their very well Planck-like spectrum. In studying their spectral energy distributions, the optical/UV excess is a long standing problem. Recently, Kaplan et al. (2011) have measured the optical/UV excess for all seven sources, which is understandable in the resonant cyclotron scattering (RCS) model previously addressed. The RCS model calculations show that the RCS process can account for the observed optical/UV excess for most sources . The flat spectrum of RX J2143.0+0654 may due to contribution from bremsstrahlung emission of the electron system in addition to the RCS process.