The presence of neutral hydrogen in the inter-stellar medium (ISM) and inter-galactic medium (IGM) induces radiative transfer (RT) effects on Ly{\alpha} photons which affect the observability of Ly{\alpha} emitters (LAEs). We use the GALFORM semi-analytic model of galaxy formation and evolution to analyse how these effects shape the spatial distribution of LAEs with respect to H{\alpha} emitters (HAEs) around high density regions at high redshift. We find that when a large sample of protoclusters is considered, HAEs showing also Ly{\alpha} emission (HAEs+LAEs) populate the same regions as those that do not display the Ly{\alpha} line at z=2.2. We compare against the protocluster USS1558-003, one of the most massive protoclusters located at z=2.53. Our results indicate that the strong depletion of HAEs+LAEs present in the high density regions of USS1558-003 may be due to cosmic variance. We find that at z=2.2 and z=3.0, RT of the ISM produces a strong decline (30-50 per cent) of the clustering amplitude of HAEs+LAEs with respect to HAEs towards the protoclusters centre. At z=5.7, given the early evolutionary state of protoclusters and galaxies, the clustering of HAEs+LAEs has a smaller variation (10-20 per cent) towards the protoclusters centre. Depending on the equivalent width and luminosity criteria of the emission-line galaxy sample, the IGM can have a mild or a null effect on galaxy properties and clustering in high density regions.
@article{arxiv.2009.13542,
title = {Are Ly{\alpha} emitters segregated in protoclusters regions?},
author = {T. Hough and S. Gurung-López and A. Orsi and S. A. Cora and C. G. Lacey and C. M. Baugh},
journal= {arXiv preprint arXiv:2009.13542},
year = {2020}
}
Comments
12 pages, 8 figures, accepted for publication in MNRAS