The Neutron Star in the Supernova Remnant PKS 1209-52

TL;DR

This study re-analyzed X-ray data of a candidate neutron star in supernova remnant PKS 1209-52 using atmosphere models, providing more realistic parameters and insights into its magnetic field and cooling behavior.

Contribution

It applies hydrogen atmosphere models to X-ray spectra, improving parameter estimates and constraining the neutron star's magnetic field and temperature.

Findings

Hydrogen atmosphere fits yield realistic NS temperature and distance.

Surface magnetic field is either very weak or very strong.

Inferred temperature aligns with standard NS cooling models.

Abstract

We re-analyzed soft X-ray data collected with the ROSAT and ASCA observatories on a candidate neutron star (NS) near the center of the supernova remnant PKS 1209-52. We fitted the observed spectra with NS atmosphere models. The hydrogen atmosphere fits yield more realistic parameters of the NS and the intervening hydrogen column than the traditional blackbody fit. In particular, for a NS of mass 1.4 M_\odot and radius 10 km, we obtained the NS surface temperature T_{eff}=(1.4-1.9)*10^6 K and distance d=1.6-3.3 kpc versus T=(4.2-4.6)*10^6 K and (implausible) d=11-13 kpc for the blackbody fit, at a 90% confidence level. Our fits suggest that the surface magnetic field is either very weak, B < 10^{10} G, or it exceeds 2*10^{12} G. The hydrogen column density inferred from the atmosphere fits, n_H=(0.7-2.2)*10^{21} cm^{-2}, agrees fairly well with independent estimates obtained from UV observations of nearby stars, radio data, and X-ray spectrum of the shell of the supernova remnant, whereas the blackbody and power-law fits give considerably lower and greater values, n_H=(0.2-0.4)*10^{21} and (5.2-7.0)*10^{21} cm^{-2}, respectively. The inferred NS surface temperature is consistent with standard NS cooling models.