Query : 2021A&A...650A..98W

2021A&A...650A..98W - Astronomy and Astrophysics, volume 650A, 98-98 (2021/6-1)

Prospects for observing the low-density cosmic web in Lyman-α emission.


Abstract (from CDS):

Mapping the intergalactic medium (IGM) in Lyman-α emission would yield unprecedented tomographic information on the large-scale distribution of baryons and potentially provide new constraints on the UV background and various feedback processes relevant to galaxy formation. In this work, we use a cosmological hydrodynamical simulation to examine the Lyman-α emission of the IGM resulting from collisional excitations and recombinations in the presence of a UV background. We focus on gas in large-scale-structure filaments in which Lyman-α radiative transfer effects are expected to be moderate. At low density the emission is primarily due to fluorescent re-emission of the ionising UV background as a result of recombinations, while collisional excitations dominate at higher densities. We discuss prospects of current and future observational facilities to detect this emission and find that the emission of filaments of the cosmic web are typically dominated by the halos and galaxies embedded in these filaments, rather than by the lower-density filament gas outside halos. Detecting filament gas directly would require a very long exposure with a MUSE-like instrument on the ELT. Our most robust predictions that act as lower limits indicate this would be slightly less challenging at lower redshifts (z≤4). We also find that there is a large amount of variance between fields in our mock observations. High-redshift protoclusters appear to be the most promising environment to observe the filamentary IGM in Lyman-α emission.

Abstract Copyright: © ESO 2021

Journal keyword(s): intergalactic medium - large-scale structure of Universe - diffuse radiation - cosmology: theory - methods: numerical

Simbad objects: 2

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Number of rows : 2
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
1 NAME Hubble Ultra Deep Field reg 03 32 39.0 -27 47 29           ~ 1685 0
2 NAME HDF-S reg 22 32 56 -60 33.0           ~ 570 0

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