Multiwavelength Observations of 2HWC J1928+177: Dark Accelerator or New TeV Gamma-Ray Binary?
Multiwavelength Observations of 2HWC J1928+177: Dark Accelerator or New TeV Gamma-Ray Binary?
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DOI：
10.3847/1538-4357/ab9631
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发表时间：
2020-05
期刊：
影响因子：
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通讯作者：
K. Mori;H. An;Q. Feng;K. Malone;R. Prado;Yvette Schutt;B. Dingus;E. Gotthelf;C. Hailey;J. Hare;O. Kargaltsev;R. Mukherjee
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文献类型：
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作者：
K. Mori;H. An;Q. Feng;K. Malone;R. Prado;Yvette Schutt;B. Dingus;E. Gotthelf;C. Hailey;J. Hare;O. Kargaltsev;R. Mukherjee
2HWC J1928+177是由高海拔水切伦科夫（HAWC）天文台探测到的银河系TeV伽玛射线源，高达~ 56 TeV。HAWC的来源，后来被高能立体系统证实，由于在低能波段没有发现明显的超新星遗迹或脉冲星风星云，因此仍未被确认为暗加速器。射电脉冲星PSR J1928+1746，与HAWC源位置一致，没有x射线对应。我们的SED模型表明，假设脉冲星风星云中的逆康普顿散射只有在看不见的星云向外延伸时才能解释TeV发射。另外，TeV伽马射线可能是由来自与射电脉冲星相关的未被探测到的超新星遗迹和附近的分子云G52.9+0.1的相对论质子之间的强子相互作用产生的。NuSTAR和钱德拉的观测在HAWC误差圈内发现了一个可变的x射线点源，可能与明亮的红外（IR）源有关。x射线光谱可以用NH =（9±3）× 1022 cm−2和ΓX = 1.6±0.3的吸收幂律模型拟合，并表现出近10年来x射线通量的长期变化。如果x射线源，可能与红外源（可能是O星）有关，是HAWC源的对应物，它可能是脉冲星风和恒星风之间碰撞产生的新的TeV伽玛射线双星。后续的x射线观测是必要的，以寻找漫射x射线发射并确定HAWC源的性质。
2HWC J1928+177 is a Galactic TeV gamma-ray source detected by the High Altitude Water Cherenkov (HAWC) Observatory up to ∼56 TeV. The HAWC source, later confirmed by the High Energy Stereoscopic System, still remains unidentified as a dark accelerator since there is no apparent supernova remnant or pulsar wind nebula detected in the lower-energy bands. The radio pulsar PSR J1928+1746, coinciding with the HAWC source position, has no X-ray counterpart. Our SED modeling shows that inverse Compton scattering in the putative pulsar wind nebula can account for the TeV emission only if the unseen nebula is extended beyond . Alternatively, TeV gamma-rays may be produced by hadronic interactions between relativistic protons from an undetected supernova remnant associated with the radio pulsar and a nearby molecular cloud G52.9+0.1. NuSTAR and Chandra observations detected a variable X-ray point source within the HAWC error circle, potentially associated with a bright infrared (IR) source. The X-ray spectra can be fitted with an absorbed power-law model with NH = (9 ± 3) × 1022 cm−2 and ΓX = 1.6 ± 0.3 and exhibit long-term X-ray flux variability over the last decade. If the X-ray source, possibly associated with the IR source (likely an O star), is the counterpart of the HAWC source, it may be a new TeV gamma-ray binary powered by collisions between the pulsar wind and stellar wind. Follow-up X-ray observations are warranted to search for diffuse X-ray emission and determine the nature of the HAWC source.