Environmental Dependence of the Nature of Gaseous Envelopes of Galaxies at z < 1

Abstract

We present new statistical study on the origin of Lyman-alpha absorption systems that are detected in QSO fields. The primary objective is to investigate environmental dependence of the relationship between galaxies and Lyman-alpha absorption systems. We find that galaxies exhibit no environmental dependence in giving rise to Lyman-alpha absorbers in their halos. Conversely, Lyman-alpha absorbers do not exhibit preference as to the environment where they reside.

4 pages, 1 figure, to appear in proceedings of the Xth Rencontres de Blois on "The Birth of Galaxies," LaTex style file included