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Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/58016
- Cross-correlation of Lyman alpha absorbers with gas-rich galaxies
- Ryan-Weber, Emma V.
- The Hi Parkes all-sky survey (HIPASS) galaxy catalogue is cross-correlated with known low redshift, low column density (NH1 < 1015 cm-2) Lyman α (Lyα) absorbers from the literature. The redshift-space correlation is found to be similar in strength to HIPASS galaxy self-clustering (correlation length s0,ag = 6 ± 4 h 100-1 Mpc and s0,gg0,gg = 3.1 ± 0.5 h100-1 Mpc, respectively). In real space the cross-correlation is stronger than the galaxy auto-correlation (correlation length r0,ag = 7.2 ± 1.4 h100-1 Mpc and r0,gg = 3.5 ± 0.7 h100-1 Mpc, respectively) on scales from 1 to 10 h100-1 Mpc, ruling out the minihalo model for the confinement Lyor absorbers at the 99 per cent confidence level. Provided that the cause of the strong cross-correlation is purely gravitational, the ratio of correlation lengths suggest that absorbers are embedded in dark matter haloes with masses log(M/M⊙) = 14.2 h 100-1, similar to those of galaxy groups. The flattening of the cross-correlation at separations less than ∼600 h100-1 kpc could correspond to the thickness of filaments in which absorbers are embedded. This work provides indirect statistical evidence for the notion that galaxy groups and large-scale filaments, particularly those that comprise gas-rich galaxies, are the dominant environments of low column density Lyα absorbers at z = 0.
- Publication type
- Journal article
- Monthly Notices of the Royal Astronomical Society, Vol. 367, no. 3 (Apr 2006), pp. 1251-1260
- Publication year
- FOR Code(s)
- 0201 Astronomical and Space Sciences
- Absorption lines; Galaxies; HI Parkes All Sky Survey; HIPASS; Intergalactic medium; Large-scale structure of Universe; Quasars; Statistics
- Publisher URL
- Copyright © 2006 Royal Astronomical Society.
- Peer reviewed