The Lyman alpha forest towards B2 1225 + 317
Open Access
- 11 February 1997
- journal article
- Published by Oxford University Press (OUP) in Monthly Notices of the Royal Astronomical Society
- Vol. 285 (1) , 167-180
- https://doi.org/10.1093/mnras/285.1.167
Abstract
We present observations of the Lyman alpha (Ly α) forest towards B2 1225 + 317 taken at a resolution of 18 km s−1. A clean sample of Ly α forest lines is extracted after a careful profile-fitting analysis and the removal of the absorption lines of heavy elements. The sample is analysed for statistical properties. Eighty per cent of the column densities are < 1014 cm−2. A single power law is inconsistent with the column density distribution and a steepening/break in the distribution is indicated. The average velocity dispersion parameter is 29.4 km s−1. We find 3σ evidence for a correlation between column density and the velocity dispersion parameter. The correlation, however, is mainly the result of narrow lines and weakens to 1.2σ if lines with a velocity dispersion parameter smaller than 20 km s−1 are excluded. An excess of line pairs with velocity separation ≤100kms−1 over the expected number is found.Keywords
All Related Versions
This publication has 0 references indexed in Scilit: