The dense warm ionized medium in the inner Galaxy
نویسندگان
چکیده
Context. Ionized interstellar gas is an important component of the medium and its lifecycle. The recent evidence for a widely distributed highly ionized warm with density intermediate between (WIM) compact H II regions suggests that there major gap in our understanding gas. Aims. Our goal to investigate properties dense WIM Milky Way using spectrally resolved SOFIA GREAT [N ] 205 μm fine-structure lines Green Bank Telescope hydrogen radio recombination (RRL) data, supplemented by unresolved Herschel PACS 122μm 12 CO. Methods. We observed eight sight (LOS) 20° < l 30° region Galactic plane. analyzed at RRL observations, along 122 emission, excitation radiative transfer models determine physical parameters WIM. derived kinetic temperature, as well thermal turbulent velocity dispersions from linewidths. Results. emission are characterized electron densities, n ( e ) ~ 10−35 cm −3 , temperatures range 3400 8500 K, nitrogen column densities N(N + 7 × 10 16 3 17 −2 . 6 20 1.7 21 fractional ion abundance x (N 1.1 −4 3.0 implying enhanced distance ~4.3 kpc Center. coincide CO although often offset velocity, which located in, or near, star-forming regions, themselves associated molecular Conclusions. These found contribute ≳50% [C intensity these LOS. we derive too low explain presence N resulting collisional ionization and/or proton charge atomic nitrogen. Rather, most likely extreme ultraviolet (EUV) radiation nearby result EUV leakage through clumpy porous medium.
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ژورنال
عنوان ژورنال: Astronomy and Astrophysics
سال: 2021
ISSN: ['0004-6361', '1432-0746']
DOI: https://doi.org/10.1051/0004-6361/202040223