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 \({\sim}250^{\prime\prime}\) in radius and a \(\beta\)-model with a characteristic size \({\sim}480^{\prime\prime}\). 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 (\(N_{\textrm{H}}\simeq 0.7\times 10^{22}\) 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 \({\simeq}2.8\)) than the pulsar spectrum (a power-law index \({\simeq}0.9\)), consistent with the predictions of theoretical models for the X-ray scattering by dust.

中文翻译：

---

来自 SRG Data 的 Pulsar 4U 1538–52 的 X 射线光环

摘要

我们展示了基于 ARC-XC 和 eROSITA 数据对脉冲星 4U 1538-52 进行 SRG 观测的第一个结果。在 0.5-8 keV 能带的源周围检测到以光晕形式存在的扩展发射。我们的模拟表明，其表面亮度分布可以通过由半径为\({\sim}250^{\prime\prime}\) 的扁平圆盘和\(\beta\) -组成的二元模型来描述具有特征尺寸\({\sim}480^{\prime\prime}\) 的模型。我们构建了能量范围为 0.5–30 keV 的 4U 1538–52 宽带光谱，可以通过弱吸收 ( \( N_{\textrm{H}}\simeq 0.7\times 10^{22}\ )厘米\({}^{-2}\)）具有高能量截止的幂律。此外，在 6-7 keV 的脉冲星光谱中检测到铁发射线。我们表明，观测到的晕光谱（幂律指数\({\simeq}2.8\)）比脉冲星光谱（幂律指数\({\simeq}0.9\) ）要软得多，与尘埃 X 射线散射理论模型的预测。