论文标题
探索银河系光环的色散度量
Exploring the dispersion measure of the Milky Way halo
论文作者
论文摘要
快速无线电爆发为银河光环中热和电离气体的质量和密度概况提供了新的约束。我们在这里测试由银河系光环的不同气体曲线预测的X射线排放和分散度量。我们检查了一系列模型，包括熵稳定性条件和外部压力连续性。我们发现，合并X射线观测的约束会导致在这些模型给出的范围的下端采用分散度量。我们表明，在我们考虑的最极端模型中，银河系的分散度度量可能小于10 cm $^{ - 3} $ PC，这是基于O VII吸收线的约束。但是，软X射线约束允许的模型范围超过分散度量的数量级。关于银河系中气体分布的其他信息，可以从偶极子的签名中获得偶极子的签名，这是在天空中快速无线电爆发的分散度量度，但这在大多数情况下将是一个很小的效果。
Fast radio bursts offer the opportunity to place new constraints on the mass and density profile of hot and ionized gas in galactic haloes. We test here the X-ray emission and dispersion measure predicted by different gas profiles for the halo of the Milky Way. We examine a range of models, including entropy stability conditions and external pressure continuity. We find that incorporating constraints from X-ray observations leads to favouring dispersion measures on the lower end of the range given by these models. We show that the dispersion measure of the Milky Way halo could be less than 10 cm$^{-3}$ pc in the most extreme model we consider, which is based on constraints from O VII absorption lines. However, the models allowed by the soft X-ray constraints span more than an order of magnitude in dispersion measures. Additional information on the distribution of gas in the Milky Way halo could be obtained from the signature of a dipole in the dispersion measure of fast radio bursts across the sky, but this will be a small effect for most cases.
