The dense warm ionized medium in the inner Galaxy
The dense warm ionized medium in the inner Galaxy
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银河系内部稠密的温暖电离介质
DOI：
10.1051/0004-6361/202040223
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发表时间：
2021
影响因子：
6.5
通讯作者：
Buchbender, C.
中科院分区：
文献类型：
--
作者：
Langer, W. D.;Pineda, J. L.;Goldsmith, P. F.;Chambers, E. T.;Riquelme, D.;Anderson, L. D.;Luisi, M.;Justen, M.;Buchbender, C.
上下文电离星际气体是星际介质及其生命周期的重要组成部分。最近的证据表明，在银河系中存在着一种广泛分布的高电离的温暖的星际气体，其密度介于温暖的电离介质（WIM）和致密的H II区之间，这表明我们对星际气体的理解存在着很大的差距。结构线和绿色班克望远镜氢射电复合线（RRL）数据，并辅以HerschelPACS [NII] 122μm光谱未分辨数据和12 CO光谱分辨数据。我们分析了205 μm的[N II]谱线和RRL观测，以及沿着的HerschelPACS 122 μm谱线，使用激发和辐射传输模型来确定稠密WIM的物理参数。我们推导出的动力学温度，以及从[N II]和RRL linewidth.ResultsThe区域与[N II] 205 μm的发射的特征在于电子密度，n（e）~ 10−35 cm−3，温度范围从3400至8500 K，和氮柱密度N（N+）~ 7 × 1016至3 × 1017 cm −2。电离氢柱密度范围为6 × 1020 ~ 1.7 × 1021 cm − 2，氮离子丰度（N+）约为1.1 × 10− 4 ~ 3.0 × 10−4，这意味着在距银心约4.3 kpc处氮离子丰度增加。[N II] 205 μm发射线与CO发射线重合，尽管通常速度存在偏移，这表明致密的温暖电离气体位于恒星形成区域中或附近，这些区域本身与分子气体相关。结论发现这些致密电离区域贡献了沿着这些LOS观察到的[C II]强度的0.50%。我们得到的动力学温度太低，无法解释N+的存在，导致电子碰撞电离和/或质子电荷转移的原子氮。相反，这些区域很可能是被来自附近恒星形成区域的极紫外线（EUV）辐射电离，或者是极紫外线通过星团和多孔星际介质泄漏的结果。
ContextIonized interstellar gas is an important component of the interstellar medium and its lifecycle. The recent evidence for a widely distributed highly ionized warm interstellar gas with a density intermediate between the warm ionized medium (WIM) and compact H II regions suggests that there is a major gap in our understanding of the interstellar gas.AimsOur goal is to investigate the properties of the dense WIM in the Milky Way using spectrally resolved SOFIA GREAT [N II] 205 μm fine-structure lines and Green Bank Telescope hydrogen radio recombination lines (RRL) data, supplemented by spectrally unresolvedHerschelPACS [N II] 122μm data, and spectrally resolved12CO.MethodsWe observed eight lines of sight (LOS) in the 20° < l < 30° region in the Galactic plane. We analyzed spectrally resolved lines of [N II] at 205 μm and RRL observations, along with the spectrally unresolvedHerschelPACS 122 μm emission, using excitation and radiative transfer models to determine the physical parameters of the dense WIM. We derived the kinetic temperature, as well as the thermal and turbulent velocity dispersions from the [N II] and RRL linewidths.ResultsThe regions with [N II] 205 μm emission are characterized by electron densities,n(e) ~ 10−35 cm−3, temperatures range from 3400 to 8500 K, and nitrogen column densities N(N+) ~ 7 × 1016to 3 × 1017cm−2. The ionized hydrogen column densities range from 6 × 1020to 1.7 × 1021cm−2and the fractional nitrogen ion abundancex(N+) ~ 1.1 × 10−4to 3.0 × 10−4, implying an enhanced nitrogen abundance at a distance ~4.3 kpc from the Galactic Center. The [N II] 205 μm emission lines coincide with CO emission, although often with an offset in velocity, which suggests that the dense warm ionized gas is located in, or near, star-forming regions, which themselves are associated with molecular gas.ConclusionsThese dense ionized regions are found to contribute ≳50% of the observed [C II] intensity along these LOS. The kinetic temperatures we derive are too low to explain the presence of N+resulting from electron collisional ionization and/or proton charge transfer of atomic nitrogen. Rather, these regions most likely are ionized by extreme ultraviolet (EUV) radiation from nearby star-forming regions or as a result of EUV leakage through a clumpy and porous interstellar medium.
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[CII]盾板中温电离介质的158微米线检测--Crux旋臂相切
DOI：
10.1051/0004-6361/201219303
发表时间：
2012
期刊：
arXiv: Astrophysics of Galaxies
影响因子：
--
作者：
T. Velusamy;W. Langer;J. Pineda;P. Goldsmith
通讯作者：
P. Goldsmith
DOI：
10.3847/1538-4365/abef65
发表时间：
2021-03
期刊：
The Astrophysical Journal Supplement Series
影响因子：
--
作者：
L. Anderson;M. Luisi;B. Liu;T. Wenger;D. Balser;T. Bania;L. M. Haffner;Dylan J. Linville;J. Ma
通讯作者：
L. Anderson;M. Luisi;B. Liu;T. Wenger;D. Balser;T. Bania;L. M. Haffner;Dylan J. Linville;J. Ma
影响因子：
8.7
作者：
R. Rubin
通讯作者：
R. Rubin
伟大：SOFIA 高频外差仪器
影响因子：
6.5
作者：
S. Heyminck;U. Graf;R. Gusten;J. Stutzki;H. Hubers;P. Hartogh
通讯作者：
P. Hartogh
激光磁共振直接测量单电离原子碳的精细结构间距和g_J因子
DOI：
10.1086/184691
发表时间：
1986
期刊：
The Astrophysical Journal
影响因子：
--
作者：
A. Cooksy;G. Blake;R. Saykally
通讯作者：
R. Saykally