Observations of the Ly-α Forest


Cite item

Full Text

Open Access Open Access
Restricted Access Access granted
Restricted Access Subscription Access

Abstract

We analyze four high resolution rich samples of Ly-α and metal lines (two at z ≥ 2 and two at z ≤ 0.2). We describe evolution of the observed Doppler parameters and absorbers separation and propose a model of the forest. We argue that all absorption lines are formed in gaseous caustics created in stable DM subclouds. The absorption lines are described by two local characteristics, the Doppler parameter and the column density of neutral hydrogen. We show that evolution of the Doppler parameter is very slow and its mean value increases by a factor ≤1.5 at redshifts 0 ≤ z ≤ 3. We show that absorbers separation increases as <dsep ∝ (1 + z)−2. We describe evolution of absorbers in the framework of a two component model: the first population represents absorbers with just one line created in compact stable DM clouds with random spatial distribution, and the second population includes absorbers with two, three and more absorption lines formed in more massive and extended random DM clouds. Slow evolution of the Doppler parameter indicates high stability of caustics and conditions within clouds. For absorbers of the second population relative velocity of lines slowly increases with time.

About the authors

M. Demiański

Institute of Theoretical Physics; Department of Astronomy

Email: dorr@asc.rssi.ru
Poland, Warsaw; Williamstown

A. Doroshkevich

Astro Space Center; National Research Center “Kurchatov Institute,”

Author for correspondence.
Email: dorr@asc.rssi.ru
Russian Federation, Moscow; Moscow

Supplementary files

Supplementary Files
Action
1. JATS XML

Copyright (c) 2018 Pleiades Publishing, Ltd.