Insight-HXMT Discovery of the Highest-energy CRSF from the First Galactic Ultraluminous X-Ray Pulsar Swift J0243.6+6124
Insight-HXMT Discovery of the Highest-energy CRSF from the First Galactic Ultraluminous X-Ray Pulsar Swift J0243.6+6124
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Insight-HXMT从第一颗银河超亮X射线脉冲星Swift J0243.6 6124中发现最高能量CRSF
DOI：
10.3847/2041-8213/ac7711
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发表时间：
2022-06
期刊：
影响因子：
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通讯作者：
et al.
中科院分区：
文献类型：
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作者：
Kong Ling-Da;Zhang Shu;Zhang Shuang-Nan;et al.
探测回旋共振散射特征是直接可靠地测量中子星星表面磁场的唯一途径。Insight-HXMT在硬X射线波段的广泛能量覆盖范围和大收集面积使我们能够探测到迄今为止已知能量最高的CRSF，在2017年第一个银河脉冲超亮X射线源（pULX）Swift J0243.6+6124爆发期间达到约146 keV。在这次爆发中，CRSF只在接近峰值光度102 × 1039 erg s−1时才显得突出，这是迄今为止银河系中最高的恒星。CRSF在对应于脉冲轮廓的主脉冲的自旋相位区域中是最显著的，并且其质心能量随相位从120到146 keV演变。我们确定这个功能的基本CRSF，因为没有光谱特征存在于60-70千电子伏。这是第一次明确地探测到来自ULX的电子CRSF。我们还估计了Swift J0243.6+6124的表面磁场为1.6 × 1013 G。考虑到偶极磁场强度，推断从几个独立的估计磁层半径，至少比我们的测量低一个数量级，我们认为，最高能量CRSF的检测报告在这里毫不含糊地证明了多极场分量的存在接近表面的中子星星。这种情况以前曾被几个脉动ULX提出过，包括Swift J0243.6+6124，我们的结果代表了这种情况的第一次直接确认。
The detection of cyclotron resonance scattering features (CRSFs) is the only way to directly and reliably measure the magnetic field near the surface of a neutron star (NS). The broad energy coverage and large collection area of Insight-HXMT in the hard X-ray band allowed us to detect the CRSF with the highest energy known to date, reaching about 146 keV during the 2017 outburst of the first galactic pulsing ultraluminous X-ray source (pULX) Swift J0243.6+6124. During this outburst, the CRSF was only prominent close to the peak luminosity of ∼2 × 1039 erg s−1, the highest to date in any of the Galactic pulsars. The CRSF is most significant in the spin-phase region corresponding to the main pulse of the pulse profile, and its centroid energy evolves with phase from 120 to 146 keV. We identify this feature as the fundamental CRSF because no spectral feature exists at 60–70 keV. This is the first unambiguous detection of an electron CRSF from an ULX. We also estimate a surface magnetic field of ∼1.6 × 1013 G for Swift J0243.6+6124. Considering that the dipole magnetic field strengths, inferred from several independent estimates of magnetosphere radius, are at least an order of magnitude lower than our measurement, we argue that the detection of the highest-energy CRSF reported here unambiguously proves the presence of multipole field components close to the surface of the neutron star. Such a scenario has previously been suggested for several pulsating ULXs, including Swift J0243.6+6124, and our result represents the first direct confirmation of this scenario.
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发表时间：
2007
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作者：
Jean-Luc Starck;F. Murtagh
通讯作者：
Jean-Luc Starck;F. Murtagh
DOI：
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发表时间：
1999
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