Quasars as probes of gas in extended protogalaxies.
Abstract
The formation of a galaxy involves infall of gas from radii ~100 kpc, at epochs corresponding to redshifts z<~3. This gas, expected to have a two-phase structure, could be highly luminous if it were irradiated by a central quasar. Evidence for extended emission-line 'fuzz' around high-z quasars (or even upper limits to the surface brightness of any such reprocessed radiation) can yield surprisingly strong clues to the nature and formation mechanism of their host galaxies. In the absence of a central quasar, infalling gas that cooled from the virial temperature to 10^4^ K would become largely neutral. Clouds or sheets of such gas, in galaxies along the line-of-sight to a background quasar, could readily give rise to at least as many HI absorption systems of high column density as are observed.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- April 1988
- DOI:
- 10.1093/mnras/231.1.91P
- Bibcode:
- 1988MNRAS.231P..91R
- Keywords:
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- Cosmology;
- Galactic Evolution;
- Galactic Nuclei;
- H I Regions;
- Quasars;
- Red Shift;
- Angular Momentum;
- Computational Astrophysics;
- High Temperature;
- Line Of Sight;
- Star Formation;
- Astrophysics