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Related papers: The Dense Warm Ionized Medium in the Inner Galaxy

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Spectra of about 150 early-type stars in the disk of the Milky Way recorded by the Far Ultraviolet Spectroscopic Explorer (FUSE) reveal absorption features from interstellar O VI, a tracer of collisionally ionized gases at temperatures near…

A group of four compact HII regions associated with the well-known 50 km/s molecular cloud is the closest site of on-going star formation to the dynamical center of the Galaxy, at a projected distance of ~6 pc. We present a study of ionized…

Astrophysics of Galaxies · Physics 2015-05-20 F. Yusef-Zadeh , J. H. Lacy , M. Wardle , B. Whitney , H. Bushouse , D. A. Roberts , R. G. Arendt

We present spectroscopic observations of ionized gas in the disk-halo regions of five edge-on galaxies, covering a wavelength range from [OII] 3727A to [SII] 6716.4A. The inclusion of the [OII] emission provides additional constraints on…

Astrophysics · Physics 2009-11-07 B. Otte , J. S. Gallagher , R. J. Reynolds

Observations of line ratios in the Milky Way's warm ionized medium (WIM) suggest that photoionization is not the only heating mechanism present. For the additional heating to explain the discrepancy it would have to have a weaker dependence…

Astrophysics of Galaxies · Physics 2015-06-12 Joshua Wiener , Ellen G. Zweibel , S. Peng Oh

We develop a kinematical model for the Milky Way Si IV-bearing gas to determine its density distribution and kinematics. This model is constrained by a column density line shape sample extracted from the {\it HST}/COS archival data, which…

Astrophysics of Galaxies · Physics 2020-05-27 Zhijie Qu , Joel N. Bregman , Edmund Hodges-Kluck , Jiang-Tao Li , Ryan Lindley

The Wisconsin H-Alpha Mapper (WHAM) is a high throughput Fabry-Perot facility developed specifically to detect and explore the warm, ionized component of the interstellar medium at high spectral resolution. It began operating at Kitt Peak,…

Astrophysics · Physics 2007-05-23 R. J. Reynolds , L. M. Haffner , G. J. Madsen

We report on a comparison between 21 cm rotation measure (RM) and the optically-thin atomic hydrogen column density (N_HI) measured towards unresolved extragalactic sources in the Galactic plane of the northern sky. HI column densities…

Astrophysics of Galaxies · Physics 2015-06-16 Tyler Foster , Roland Kothes , Joanne Brown

The inner 300-500 pc of the Milky Way has some of the most extreme gas conditions in our Galaxy. Physical properties of the Central Molecular Zone (CMZ), including temperature, density, thermal pressure, and turbulent pressure, are key…

Astrophysics of Galaxies · Physics 2023-03-21 Tierra M. Candelaria , E. A. C Mills , David S. Meier , Juergen Ott , Natalie Butterfield

The first all-sky maps of the diffuse emission of high ionization lines observed in X-rays by SRG/eROSITA, provide an excellent probe for the study of the warm-hot phase (T~10^6 K) of the circumgalactic medium (CGM) of the Milky Way (MW).…

Astrophysics of Galaxies · Physics 2024-01-24 N. Locatelli , G. Ponti , X. Zheng , A. Merloni , W. Becker , J. Comparat , K. Dennerl , M. J. Freyberg , M. Sasaki , M. C. H. Yeung

HIFI GOT C+ Galactic plane [CII] spectral survey has detected strong emission at the spiral arm tangencies. We use the unique viewing geometry of the Scutum-Crux (S-C) tangency near i = 30degs to detect the warm ionized medium (WIM)…

Astrophysics of Galaxies · Physics 2015-06-05 T. Velusamy , W. D. Langer , J. L. Pineda , P. F. Goldsmith

The warm-hot intergalactic medium (warm-hot IGM, or WHIM) pervades the filaments of the Cosmic Web and harbours half of the Universe's baryons. The WHIM's thermodynamic properties are notoriously hard to measure. Here we estimate a galaxy…

We present JWST/MIRI spectra from the Medium-Resolution Spectrometer of IZw18, a nearby dwarf galaxy with a metallicity of $\sim$3% Solar. Its proximity enables a detailed study of highly ionized gas that can be interpreted in the context…

Analysis of interstellar absorption lines observed in high-resolution {\em HST} spectra of nearby stars provides temperatures, turbulent velocities, and kinetic properties of warm interstellar clouds. Previous studies identified 15 warm…

Astrophysics of Galaxies · Physics 2022-08-31 Jeffrey L. Linsky , Seth Redfield , Diana Ryder , Adina Chasan-Taber

We have used the WHAM H_alpha survey and Leiden/Dwingeloo HI data to decompose the Far-infrared emission (from 100 to 1000 micron) at high Galactic latitude into components associated with the Warm Ionised Medium (WIM) and the Warm Neutral…

Astrophysics · Physics 2011-03-28 G. Lagache , L. M. Haffner , R. J. Reynolds , S. L. Tufte

The molecular gas in the Central Molecular Zone (CMZ) of the Galaxy has been studied using infrared absorption spectra of H$_3^+$ lines at 3.5-4.0 $\mu$m and CO lines near 2.34 $\mu$m. In addition to the previously reported spectra of these…

High Energy Astrophysical Phenomena · Physics 2019-10-14 Takeshi Oka , T. R. Geballe , Miwa Goto , Tomonori Usuda , Benjamin , J. McCall , Nick Indriolo

The 500 central pc of the Galaxy (hereafter GC) exhibit a widespread gas component with a kinetic temperature of 100-200 K. The bulk of this gas is not associated to the well-known thermal radio continuum or far infrared sources like Sgr A…

Astrophysics · Physics 2009-11-10 N. J Rodriguez-Fernandez , J. Martin-Pintado , A. Fuente , T. L. Wilson

We present an analysis of the diffuse ionised gas (DIG) in a high-resolution simulation of an isolated Milky Way-like galaxy, incorporating on-the-fly radiative transfer and non-equilibrium thermochemistry. We utilise the Monte-Carlo…

The [CII] 158um fine-structure line is the brightest emission line observed in local star-forming galaxies. As a major coolant of the gas-phase interstellar medium, [CII] balances the heating, including that due to far-ultraviolet photons,…

[Abridged] The [CII] 158um line is an important tool for understanding the life cycle of interstellar matter. Ionized carbon is present in a variety of phases of the interstellar medium, including the diffuse ionized medium, warm and cold…

Astrophysics of Galaxies · Physics 2015-06-15 Jorge L. Pineda , William D. Langer , Thangasamy Velusamy , Paul F. Goldsmith

I review studies of the hot gaseous medium in and around nearby normal disk galaxies, including the Milky Way. This medium represents a reservoir of materials required for lasting star formation, a depository of galactic feedback (e.g.,…

Astrophysics · Physics 2009-11-11 Q. Daniel Wang