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We use high-resolution hydrodynamical simulations to investigate the spatial correlation between weak (N(HI) <10^{15} cm^{-2}) Ly-alpha absorbers and gas-rich galaxies in the local universe. We confirm that Ly-alpha absorbers are preferentially expected near gas-rich galaxies and that the degree of correlation increases with the column density of the absorber. The real-space galaxy auto-correlation is stronger than the cross-correlation (correlation lengths r_{0,gg}=3.1 pm 0.1 Mpc/h and r_{0,ag}=1.4 pm 0.1 Mpc/h, respectively), in contrast with the recent results of Ryan-Weber (2006, RW06), and the auto-correlation of absorbers is very weak. These results are robust to the presence of strong galactic winds in the hydrodynamical simulations. In redshift-space a further mismatch arises since at small separations the distortion pattern of the simulated galaxy-absorber cross-correlation function is different from the one measured by RW06. However, when sampling the intergalactic medium along a limited number of lines-of-sight, as in the real data, uncertainties in the cross correlation estimates are large enough to account for these discrepancies. Our analysis suggests that the statistical significance of difference between the cross-correlation and auto-correlation signal in current datasets is ~ 1-sigma only.
In 2000, we started the program ``Building the Bridge between Damped Ly-alpha Absorbers and Lyman-Break Galaxies: Ly-alpha Selection of Galaxies at the European Southern Observatorys Very Large Telescope. This project is an attempt to use Ly-alpha se
We report Hubble Space Telescope Cosmic Origins Spectrograph far-ultraviolet and Arecibo Telescope H{sc i} 21cm spectroscopic studies of six damped and sub-damped Lyman-$alpha$ absorbers (DLAs and sub-DLAs, respectively) at $z lesssim 0.1$, that have
Abundances of the volatile elements S and Zn have now been measured in around 80 individual stars in the Sculptor dwarf spheroidal galaxy, covering the metallicity range $-2.4leqtext{[Fe/H]}leq-0.9$. These two elements are of particular interest as t
We present the results of a photometric and spectroscopic survey of 321 Lyman break galaxies (LBGs) at z ~ 3 to investigate systematically the relationship between Lya emission and stellar populations. Lya equivalent widths (EW) were calculated from
Using the GAEA semi-analytic model, we analyse the connection between Damped Lyman-$alpha$ systems (DLAs) and HI in galaxies. Our state-of-the-art semi-analytic model is tuned to reproduce the local galaxy HI mass function, and that also reproduces o