Gaussian analysis of new, high-angular-resolution interstellar 21-cm neutral hydrogen emission profile structure more clearly reveals the presence of the previously reported signature of the critical ionization velocity (CIV) of helium (34 km s−1). The present analysis includes 1496 component line widths for 178 neutral hydrogen profiles in two areas of sky at galactic latitudes around −50°, well away from the galactic plane. The new data considered here allow the interstellar abundance of helium to be calculated, and the derived value of 0.095 ± 0.020 agrees extremely well with the value of 0.085 for the cosmic abundance based on solar data. Although the precise mechanisms that give rise to the CIV effect in interstellar space are not yet understood, our results may provide additional motivation for further theoretical study of how the mechanism operates.

中文翻译：

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星际空间中临界电离速度效应的作用和衍生的氦丰度

对新的高角分辨率星际 21 厘米中性氢发射剖面结构的高斯分析更清楚地揭示了先前报道的氦临界电离速度 (CIV) (34 km s-1) 特征的存在。目前的分析包括 178 个中性氢剖面的 1496 个分量线宽，它们位于银河纬度 -50° 左右的两个天空区域，远离银河平面。此处考虑的新数据允许计算氦的星际丰度，并且导出值 0.095 ± 0.020 与基于太阳数据的宇宙丰度值 0.085 非常吻合。虽然在星际空间引起 CIV 效应的确切机制尚不清楚，