X-ray Halo of the Pulsar 4U 1538-52 from SRG Data
Abstract
We present the first results of the SRG observation of the pulsar 4U 1538-52 based on ARC-XC and eROSITA data. An extended emission in the form of a halo is detected around the source in the 0.5-8 keV energy band. Our simulation has shown that its surface brightness distribution can be described by a two-component model composed of a flat disk ${∼}250^''$ in radius and a $β$-model with a characteristic size ${∼}480^''$. We have constructed a broadband spectrum of 4U 1538-52 in the energy range 0.5-30 keV, which can be fitted by a weakly absorbed ($N_{\textrm{H}}∼eq 0.7× 10^{22}$ cm${}^{-2}$) power law with a high-energy cutoff. In addition, iron emission lines are detected in the pulsar spectrum at 6-7 keV. We show that the observed halo spectrum is considerably softer (a power-law index ${∼eq}2.8$) than the pulsar spectrum (a power-law index ${∼eq}0.9$), consistent with the predictions of theoretical models for the X-ray scattering by dust.
- Publication:
-
Astronomy Letters
- Pub Date:
- May 2023
- DOI:
- 10.1134/S1063773723050031
- Bibcode:
- 2023AstL...49..240S
- Keywords:
-
- X-ray pulsars;
- neutron stars;
- 4U 1538-52