Large-Scale Structure of Short-Lived Lyman\alpha Emitters

Abstract

Recently discovered large-scale structure of Ly\alpha Emitters (LAEs) raises a novel challenge to the cold dark matter (CDM) cosmology. The structure is extended over more than 50 Mpc at redshift z=3.1, and exhibits a considerably weak angular correlation. Such properties of LAE distributions appear to be incompatible with the standard biased galaxy formation scenario in the CDM cosmology. In this paper, by considering the possibility that LAEs are short-lived events, we attempt to build up the picture of LAEs concordant with the CDM cosmology. We find that if the lifetime of LAEs is as short as (6.7 \pm 0.6) \times 10^7 yr, the distributions of simulated galaxies successfully match the extension and morphology of large-scale structure of LAEs at z=3.1, and also the weak angular correlation function. This result implies that LAEs at z=3.1 do not necessarily reside in high density peaks, but tends to be located in less dense regions, in a different way from the expectation by the standard biased galaxy formation scenario. In addition, we make a prediction for the angular correlation function of LAEs at redshifts higher than 3. It is found that the prediction deviates from that by the standard biased galaxy formation scenario even at redshifts 4 < z < 6.Comment: 5 pages, 4 figures, accepted for publication in MNRA