脉冲星的阿雷西博多历元HI吸收测量：微尺度原子结构
Arecibo Multi-Epoch HI Absorption Measurements Against Pulsars: Tiny-Scale Atomic Structure
摘要：
我们提出的结果，从多历元中性氢（HI）吸收观测的六个明亮的恒星与阿雷西博望远镜。这些恒星以10- 150 AU/yr的横向速度在星际介质中运动，在我们的实验过程中扫过1- 200 AU，使我们能够探测冷中性介质中微尺度原子结构（TSAS）的存在和性质。虽然大多数观测到的恒星在HI吸收光谱上没有显着变化，但我们已经确定了至少两个明显的TSAS引起的不透明度变化，方向是B1929+10。这些观测需要TSAS云本身的物理特性或云的星系分布具有很强的空间不均匀性。虽然TSAS偶尔会在10 AU的空间尺度上被检测到，但它太罕见了，无法像以前的一些工作所建议的那样，在10-1000 AU的尺度上以湍流CNM波动谱为特征。在B1929+10方向上，TSAS和温暖的本地气泡（LB）内部的星际云之间的明显相关性表明，TSAS可能通过流体动力学不稳定性跟踪LB壁的破碎。虽然类似的碎裂事件在整个ISM中频繁发生，但这些冷云团周围的温暖介质引起了自然选择效应，其中小的TSAS云迅速蒸发并且很少，而大的云存活时间更长，成为ISM的一般属性。
英文摘要：
We present results from multi-epoch neutral hydrogen (HI) absorption observations of six bright pulsars with the Arecibo telescope. Moving through the interstellar medium (ISM) with transverse velocities of 10--150 AU/yr, these pulsars have swept across 1--200 AU over the course of our experiment, allowing us to probe the existence and properties of the tiny scale atomic structure (TSAS) in the cold neutral medium (CNM). While most of the observed pulsars show no significant change in their HI absorption spectra, we have identified at least two clear TSAS-induced opacity variations in the direction of B1929+10. These observations require strong spatial inhomogeneities in either the TSAS clouds' physical properties themselves or else in the clouds' galactic distribution. While TSAS is occasionally detected on spatial scales down to 10 AU, it is too rare to be characterized by a spectrum of turbulent CNM fluctuations on scales of 10-1000 AU, as previously suggested by some work. In the direction of B1929+10, an apparent correlation between TSAS and interstellar clouds inside the warm Local Bubble (LB) indicates that TSAS may be tracing the fragmentation of the LB wall via hydrodynamic instabilities. While similar fragmentation events occur frequently throughout the ISM, the warm medium surrounding these cold cloudlets induces a natural selection effect wherein small TSAS clouds evaporate quickly and are rare, while large clouds survive longer and become a general property of the ISM.
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。
