Multiwavelength Observation Campaign of the TeV Gamma-Ray Binary HESS J0632 + 057 with NuSTAR, VERITAS, MDM, and Swift
Multiwavelength Observation Campaign of the TeV Gamma-Ray Binary HESS J0632 + 057 with NuSTAR, VERITAS, MDM, and Swift
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DOI：
10.3847/1538-4357/ac2c6a
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发表时间：
2021-10
期刊：
影响因子：
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通讯作者：
Y. M. Tokayer;H. An;J. Halpern;J. Kim;K. Mori;C. Hailey;C. Adams;W. Benbow;A. Brill;
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文献类型：
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作者：
Y. M. Tokayer;H. An;J. Halpern;J. Kim;K. Mori;C. Hailey;C. Adams;W. Benbow;A. Brill;
HESS J 0632 +057属于一个罕见的双星系统，它能发射100 GeV以上的伽马射线。它以其独特的高能光变曲线而闻名，其特点是尖锐的“主”峰和更宽的“次”峰。我们介绍了努斯塔和VERITAS在2019年12月至2020年2月期间的第二个峰值期间的同期观测结果，当时轨道相位（θ）在0.55和0.75之间。努斯塔探测到X射线光谱演化，而VERITAS探测到TeV辐射。我们拟合轻子风碰撞模型的多波长光谱数据获得的四个努斯塔和VERITAS观测，约束脉冲星自旋的亮度和磁化参数在冲击。尽管从2019年10月到2020年3月对源进行了长期监测，但MDM天文台没有检测到Hα和Hβ线等效宽度的显著变化，这是Be盘与脉冲星相互作用的预期特征。此外，用双星内激波模型拟合折叠的Swift-XRT光变曲线数据限制了轨道参数，表明脉冲星穿过Be盘的两个轨道相位（在θ D = 0.13和0.37），以及近星点相位（θ 0 = 0.30）和下合相位（θ IFC = 0.75）。使用Swift-XRT和努斯塔的宽带X射线光谱使我们能够在预测的磁盘通过阶段之一测量更高的中性氢柱密度。
HESS J0632+057 belongs to a rare subclass of binary systems that emit gamma rays above 100 GeV. It stands out for its distinctive high-energy light curve, which features a sharp “primary” peak and broader “secondary” peak. We present the results of contemporaneous observations by NuSTAR and VERITAS during the secondary peak between 2019 December and 2020 February, when the orbital phase (ϕ) is between 0.55 and 0.75. NuSTAR detected X-ray spectral evolution, while VERITAS detected TeV emission. We fit a leptonic wind-collision model to the multiwavelength spectra data obtained over the four NuSTAR and VERITAS observations, constraining the pulsar spin-down luminosity and the magnetization parameter at the shock. Despite long-term monitoring of the source from 2019 October to 2020 March, the MDM observatory did not detect significant variation in Hα and Hβ line equivalent widths, an expected signature of Be-disk interaction with the pulsar. Furthermore, fitting folded Swift-XRT light-curve data with an intrabinary shock model constrained the orbital parameters, suggesting two orbital phases (at ϕ D = 0.13 and 0.37), where the pulsar crosses the Be-disk, as well as phases for the periastron (ϕ 0 = 0.30) and inferior conjunction (ϕ IFC = 0.75). The broadband X-ray spectra with Swift-XRT and NuSTAR allowed us to measure a higher neutral hydrogen column density at one of the predicted disk-passing phases.