The warm ionized medium in spiral galaxies
نویسنده
چکیده
This article reviews observations and models of the diffuse ionized gas that permeates the disk and halo of our Galaxy and others. It was inspired by a series of invited talks presented during an afternoon scientific session of the 65th birthday celebration for Professor Carl Heiles held at Arecibo Observatory in August 2004. This review is in recognition of Carl’s long standing interest in and advocacy for studies of the ionized as well as the neutral components of the interstellar medium.
منابع مشابه
The Warm Ionized Medium in Spiral Galaxies: A View from Above
The Warm Ionized Medium (WIM), also refered to as Diffuse Ionized Gas, contains most of the mass of interstellar medium in ionized form, contributing as much as 30% of the total atomic gas mass in the solar neighborhood. The advent of CCDs has enabled unprecedented study of this medium in external galaxies, probing a variety of environments. In particular, we can derive the morphology of the WI...
متن کاملMeasurements of He I λ5876 Recombination Line Radiation from the Diffuse, Warm Ionized Medium in Irregular Galaxies
We present longslit optical spectroscopy of three high surface brightness Magellanic irregular galaxies. This paper draws attention to our detection of He I λ5876 line emission from the ionized gas outside the HII regions, or the warm ionized phase of the interstellar medium. We measure a mean reddening-corrected intensity ratio of He I λ5876 / Hα ≈ 0.041 independent of spatial location. This r...
متن کاملCII ] emission and star formation in the spiral arms of M 31 ⋆
Context. The [Cii] 158 μm line is the most important coolant of the interstellar medium in galaxies but substantial variations are seen from object to object. The main source of the emission at a galactic scale is still poorly understood and candidates range from photodissociation regions (PDRs) to the cold neutral or diffuse warm ionized medium. Previous studies of the [Cii] emission in galaxi...
متن کاملGas cooling within the diffuse ISM of late–type galaxies
We combine observations of spiral galaxies in the [CII] line at 158 μm, made with the Long Wavelength Spectrometer aboard ISO, with previous data from the Kuiper Airborne Observatory to study the origin of this line, which is the main coolant of the interstellar medium at relatively low temperatures. We also use HI and CO(10) observations of these galaxies and estimate the respective line fluxe...
متن کاملExtraplanar Dust in Spiral Galaxies: Observations and Implications
Recent optical and submillimeter observations have begun to probe the existence of dust grains in the halos of spiral galaxies. I review our own work in this area which employs high-resolution optical images of edge-on spiral galaxies to trace high-z dust in absorption against the background stellar light of the galaxies. We have found that a substantial fraction of such galaxies (> 50%) show e...
متن کامل