论文标题
4U 1901+03在2019年爆发中使用Swift和Nustar观测值的时间和光谱特征的演变
Evolution of timing and spectral characteristics of 4U 1901+03 during its 2019 outburst using the Swift and NuSTAR observatories
论文作者
论文摘要
我们报告了瞬态X射线脉冲星的详细计时和光谱研究的结果，2019年爆发期间4U 1901+03。我们在1-70 keV能量带中使用了四个在不同强度水平下用迅捷和nustar做出的观察结果。我们的时序结果揭示了高度可变的脉冲特征，取决于光度和能量。我们的光谱结果表明，在〜30 keV处存在回旋共振散射特征（CRSF）。 30 KEV的此功能是高度光度和脉冲相关的。在最后两个观察结果中，相位平均的光谱接近爆发的阶段的下降，显示了该特征在30 keV左右的存在。在这些观察过程中，在30 keV处存在CRSF的存在得到了脉冲图的突然变化，发现脉冲曲线的形状接近该能量。我们还发现，在相对较高的亮度下进行的观测值的脉冲分辨率光谱中显着检测到30个KEV特征。此外，所有光谱拟合参数均显示出强脉冲相位的依赖性。与先前的发现一致，在所有观测值的相平均X射线光谱中显着观察到在10 keV处的吸收特征，并且还显示出强脉冲相位依赖性。
We report the results from a detailed timing and spectral study of transient X-ray pulsars, 4U 1901+03 during its 2019 outburst. We performed broadband spectroscopy in the 1-70 keV energy band using four observations made with Swift and NuSTAR at different intensity levels. Our timing results reveal the presence of highly variable pulse profiles dependent on both luminosity and energy. Our spectroscopy results showed the presence of a cyclotron resonance scattering feature (CRSF) at ~30 keV. This feature at 30 keV is highly luminosity and pulse-phase dependent. Phase-averaged spectra during the last two observations, made close to the declining phase of the outburst showed the presence of this feature at around 30 keV. The existence of CRSF at 30 keV during these observations is well supported by an abrupt change in the shape of pulse profiles found close to this energy. We also found that 30 keV feature was significantly detected in the pulse-phase resolved spectra of observations made at relatively high luminosities. Moreover, all spectral fit parameters showed a strong pulse phase dependence. In line with the previous findings, an absorption feature at around 10 keV is significantly observed in the phase-averaged X-ray spectra of all observations and also showed a strong pulse phase dependence.
