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arXiv 1708.04082astro-ph.HE
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逃逸恒星弓形激波的X射线研究

X-ray study of bow shocks in runaway stars

M. De Becker, M. V. del Valle, G. E. Romero, C. S. Peri, P. Benaglia

摘要:

大质量的逃逸恒星通过其风与星际介质的相互作用产生弓形激波,并有可能通过激波加速粒子。因此,这些物体是非热发射的候选者。我们的目的是研究这些源的X射线发射。我们用XMM-牛顿观测了5个弓形激波逃逸的样本,这是迄今为止在X射线中研究的弓形激波逃逸样本的显著改进。对数据的仔细分析没有发现任何与弓形激波有关的X射线发射。然而,探测到恒星的X射线发射,与预期的恒星风热发射一致。背景测量的基础上,我们得到保守的上限在0.3和10千电子伏之间的弓冲击发射。使用一个简单的辐射模型,这些限制与无线电上限允许我们约束的非热发射过程中涉及的一些主要物理量,如磁场强度和入射红外光子的量。对非热辐射探测不到的原因进行了讨论。最后,使用能量预算参数,我们调查的逆康普顿X射线的可探测性在一个更广泛的样本编目失控星弓冲击。从我们的分析中,我们得出结论,一个清晰的识别非热X射线从大规模失控的弓冲击需要一个数量级(或更高)的灵敏度改善相对于目前的天文台。

英文摘要:

Massive runaway stars produce bow shocks through the interaction of their winds with the interstellar medium, with the prospect for particle acceleration by the shocks. These objects are consequently candidates for non-thermal emission. Our aim is to investigate the X-ray emission from these sources. We observed with XMM-Newton a sample of 5 bow shock runaways, which constitutes a significant improvement of the sample of bow shock runaways studied in X-rays so far. A careful analysis of the data did not reveal any X-ray emission related to the bow shocks. However, X-ray emission from the stars is detected, in agreement with the expected thermal emission from stellar winds. On the basis of background measurements we derive conservative upper limits between 0.3 and 10 keV on the bow shocks emission. Using a simple radiation model, these limits together with radio upper limits allow us to constrain some of the main physical quantities involved in the non-thermal emission processes, such as the magnetic field strength and the amount of incident infrared photons. The reasons likely responsible for the non-detection of non-thermal radiation are discussed. Finally, using energy budget arguments, we investigate the detectability of inverse Compton X-rays in a more extended sample of catalogued runaway star bow shocks. From our analysis we conclude that a clear identification of non-thermal X-rays from massive runaway bow shocks requires one order of magnitude (or higher) sensitivity improvement with respect to present observatories.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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