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arXiv 1401.3255astro-ph.HE
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逃逸大质量恒星作为可变gamma-ray源

Runaway massive stars as variable gamma-ray sources

Maria V. del Valle, Gustavo E. Romero

摘要:

逃逸恒星从它们的形成地喷出,位于巨大的暗云的分子核心内。最终,这些恒星可以穿过高度不均匀的分子云。大质量逃逸恒星的强大风与介质相互作用形成弓形激波。最近的观测和理论模型表明,这些弓形激波发出非热辐射。当大质量恒星穿过不均匀的环境气体时,弓形激波的物理性质被改变,产生非热辐射的变化。我们的目标是计算逃逸的大质量恒星在穿过分子云时产生的弓形激波的非热辐射。我们计算了两种类型的大质量逃逸恒星,O9I和O4I的非热发射和吸收,因为它们通过密度梯度移动。我们提出的光谱能量分布的逃逸星建模。此外,我们还获得了不同能量范围内的光变曲线。我们发现显着的变化,在排放的时间尺度为$\sim$ 1年。我们的结论是,弓冲击的大规模失控的恒星,在某些假设下,可能是可变的伽马射线源,与可变的时间尺度,取决于中等密度的配置文件。这些物体可能构成了银河系伽马射线源的种群,在几年内开启和关闭。

英文摘要:

Runaway stars are ejected from their formation sites well within molecular cores in giant dark clouds. Eventually, these stars can travel through the molecular clouds, which are highly inhomogeneous. The powerful winds of massive runaway stars interact with the medium forming bowshocks. Recent observations and theoretical modelling suggest that these bowshocks emit non-thermal radiation. As the massive stars move through the inhomogeneous ambient gas the physical properties of the bowshocks are modified, producing changes in the non-thermal emission. We aim to compute the non-thermal radiation produced in the bowshocks of runaway massive stars when travelling through a molecular cloud. We calculate the non-thermal emission and absorption for two types of massive runaway stars, an O9I and an O4I, as they move through a density gradient. We present the spectral energy distributions for the runaway stars modelled. Additionally, we obtain light curves at different energy ranges. We find significant variations in the emission over timescales of $\sim$ 1 yr. We conclude that bowshocks of massive runaway stars, under some assumptions, might be variable gamma-ray sources, with variability timescales that depend on the medium density profile. These objects might constitute a population of galactic gamma-ray sources turning on and off within years.

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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