Year: 2021
Type: article
Abstract: 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.
Source: Astronomy and Astrophysics
Authors: Joris Witstok, Ewald Puchwein, Girish Kulkarni, Renske Smit, Martin G. Haehnelt
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G1736745720, G1771230537, G2073976794, G2724489712, G3403823835, G3531124447, G3563244976, G4830815193, G5562923697, G5660267321, G5768834005, Computing Resources and Software Support for the UKQCD Physics Programme., G6537386148, G6692562399, G6802598382, G6873874887, G6901566080, G6926846737, Computing Resources and Software Support for the UKQCD Physics Programme., G7108246583, The Structure of the Universe: Cosmology, Exoplanets and Lattice QCD, G7521014512, G7573294876, G7810866252, G7937591081, G8211594416, Dissecting galaxies at the cosmic dawn, G8710138095, G8718642859, G878803593
OpenAlex ID: W3137776177