弥漫和半透明分子云中的密度：基于C₂观测和三维消光图的估算
星系天体物理
2024-09-04 v2
摘要
最近由Najar和Kalugina（2020）提出的C₂与H₂碰撞激发的新碰撞速率系数，显著大于先前在C₂分子激发模型中所采用的值，而C₂分子是广泛使用的星际气体密度探针。利用这些新的速率系数，我们对来自46个邻近背景源的C₂电子跃迁的可见光和紫外吸收观测所推断出的C₂转动分布进行了建模。推断出的前景星际云中导致观测到的C₂吸收的气体密度，比先前推断的值小4到7倍，这直接反映了Najar和Kalugina（2020）计算出的较大碰撞速率系数。这些较低的密度估计与相关视线方向上三维消光图推断的峰值密度总体吻合良好。在同时观测到H₃⁺吸收并用于估算宇宙射线电离率（CRIR）的情况下，我们对其的估算也将相应降低，因为H₃⁺的丰度是CRIR与气体密度之比的函数。
引用
@article{arxiv.2408.11108,
title = {The densities in diffuse and translucent molecular clouds: estimates from observations of C$_2$ and from 3-dimensional extinction maps},
author = {David A. Neufeld and Daniel E. Welty and Alexei V. Ivlev and Paola Caselli and Gordian Edenhofer and Nick Indriolo and Marta Obolentseva and Kedron Silsbee and Paule Sonnentrucker and Mark G. Wolfire},
journal= {arXiv preprint arXiv:2408.11108},
year = {2024}
}
备注
46 pages, 11 figures, 1 figure set with 23 figures, accepted for publication in the Astrophysical Journal. Version 2: An error is corrected in Table 2, in which values listed in two of the columns were jumbled in Version 1. There are no other changes