2005/07/26 by Hsiao-Wen Chen, Jason X. Prochaska, Benjamin J. Weiner +2
Physics and Astronomy · #Amplitude #Astronomy and Astrophysical Research #Galaxies: Formation, Evolution, Phenomena #Galaxy #Halo #Intergalactic medium #Intergalactic travel #Projection (relational algebra) #Quasar #Radio Astronomy Observations and Technology #astro-ph
paper · pdf · doi:10.1086/444377
published as Astrophys.J.629:L25-L28,2005 · 5 pages, including 2 figures; to appear in ApJ Letters, the 2005 August 10 issue
arxiv created 2005/07/26 · openalex publication_date 2005/07/27 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present a pilot study of the clustering properties of Lyα absorbers with respect to known galaxies based on 112 Lyα absorbers and 482 galaxies identified at z < 0.5 along the sight line toward PKS 0405-123. The principal goal is to determine the origin of Lyα absorbers based on their cross-correlation amplitude with known galaxies and to investigate a possible N (H I) dependence of the cross-correlation function. The main results of our study are as follows: (1) The cross-correlation function ξ ga measured using only emission-line-dominated galaxies and Lyα absorbers with log N (H I) ≥ 14 shows a comparable strength to the galaxy autocorrelation function ξ gg on comoving, projected distance scales of less than 1 h -1 Mpc, while there remains a lack of cross-correlation signal when using only absorption-line-dominated galaxies. This signifies a morphology-dependent ξ ga and indicates that strong absorbers with log N (H I) ≥ 14 and emission-line galaxies reside in the same halo population. (2) A maximum likelihood analysis shows that Lyα absorbers with log N (H I) < 13.6 are consistent with being more randomly distributed with respect to known galaxies. (3) Finally, we find based on this single sight line that the amplitude of ξ ga does not depend sensitively on N (H I) for strong absorbers, with log N (H I) ≥ 13.6.