Ionized Hydrogen at Large Galactocentric Distances
Abstract
We summarize recent attempts to detect warm ionized gas at large galactocentric distances. This includes searching for gas at the edges of spirals, in between cluster galaxies, towards extragalactic HI clouds, and towards high velocity clouds and the Magellanic Stream in the Galaxy. With the exception of extragalactic HI clouds, all of these experiments have proved successful. Within each class, we have only observed a handful of objects. It is premature to assess what fraction of the missing baryonic mass fraction might be in the form of ionized gas. But, in most cases, the detections provide a useful constraint on the ambient ionizing flux, and in the case of spiral edges, can even trace dark matter haloes out to radii beyond the reach of radio telescopes.
Cite
@article{arxiv.astro-ph/9704141,
title = {Ionized Hydrogen at Large Galactocentric Distances},
author = {J. Bland-Hawthorn},
journal= {arXiv preprint arXiv:astro-ph/9704141},
year = {2015}
}
Comments
5 pages; Latex; 1 encapsulated postscript figure. Presented at the workshop `HI in the Local Universe', Sydney, May 13-15 1996. Accepted for publication by Publications of the Astronomical Society of Australia. Also available from http://www.atnf.csiro.au/pasa/14_1/