The distribution of QSO absorption system column densities - Evidence for a single population

Abstract

view Abstract Citations (189) References (102) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Distribution of QSO Absorption System Column Densities: Evidence for a Single Population Tytler, David Abstract The distribution of H I column densities in a representative sample of all cosmologically distributed QSO absorption-line systems is examined. Remarkably, this distribution function f(N) is a featureless power law extending over about seven orders of magnitude in column density. It is argued that this finding is in conflict with the standard interpretation of absorption systems, which invokes separate and unrelated intergalactic (Ly-alpha) and galactic halo (metal-line) absorption systems. A more natural explanation is that both the Ly-alpha and metal-line systems belong to the same population. They would have the same origins and the same spatial locations. The simplest possibility, that they all have the same high metal abundances, is considered to be unlikely, even though it does offer straightforward explanations for four different observational enigmas. However, it is entirely possible that the majority of Ly-alpha systems (those with low H I column densities) contain metals. Possible physical origins for the power-law form of f(N) are also discussed. Publication: The Astrophysical Journal Pub Date: October 1987 DOI: 10.1086/165615 Bibcode: 1987ApJ...321...49T Keywords: Absorption Spectra; H I Regions; Intergalactic Media; Line Spectra; Quasars; Spectral Energy Distribution; Astronomical Models; Distribution Functions; Lyman Alpha Radiation; Metallicity; Astrophysics; COSMOLOGY; GALAXIES: INTERGALACTIC MEDIUM; LINE IDENTIFICATIONS; QUASARS full text sources ADS | data products NED (62) SIMBAD (57)