Prospects for Observing the low-density Cosmic Web in Lyman-alpha Emission

Abstract

Mapping the intergalactic medium (IGM) in Lyman-$\alpha$ 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. Here, we use a cosmological hydrodynamical simulation to examine the Lyman-$\alpha$ emission of the IGM due to collisional excitations and recombinations in the presence of a UV background. We focus on gas in large-scale-structure filaments in which Lyman-$\alpha$ 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 due to 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 will typically be dominated by the halos and galaxies embedded in them, 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 ($z\lesssim 4$). 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-$\alpha$ emission.

20 pages, 13 figures. Accepted for publication in Astronomy & Astrophysics. Accepted version contains several revisions following suggestions made in the review process

References in corpus (29)

• The NumPy array: a structure for efficient numerical computation
• 3D Lyman-alpha radiation transfer. I. Understanding Lyman-alpha line profile morphologies
• The MUSE Hubble Ultra Deep Field Survey: I. Survey description, data reduction and source detection
• Lyman Alpha Emitting Galaxies as a Probe of Reionization
• Large Lyman-alpha opacity fluctuations and low CMB tau in models of late reionization with large islands of neutral hydrogen extending to z<5.5
• Quasar Quartet Embedded in Giant Nebula Reveals Rare Massive Structure in Distant Universe
• Evolution of the Intergalactic Opacity: Implications for the Ionizing Background, Cosmic Star Formation, and Quasar Activity
• A Population of Faint Extended Line Emitters and the Host Galaxies of Optically Thick QSO Absorption Systems
• The MUSE 3D view of the Hubble Deep Field South
• QSO MUSEUM I: A sample of 61 extended Ly$\alpha$-emission nebulae surrounding $z\sim 3$ quasars
• Gas filaments of the cosmic web located around active galaxies in a proto-cluster
• Diffuse Lyman-alpha Halos around Galaxies at z=2.2-6.6: Implications for Galaxy Formation and Cosmic Reionization
• Nearly all the sky is covered by Lyman-alpha emission around high redshift galaxies
• Self-Consistent Modeling of Reionization in Cosmological Hydrodynamical Simulations
• MUSE searches for galaxies near very metal-poor gas clouds at z~3: new constraints for cold accretion models
• Mapping Neutral Hydrogen During Reionization with the Ly-alpha Emission from Quasar Ionization Fronts
• The MUSE Extremely Deep Field: the Cosmic Web in Emission at High Redshift
• VIMOS-VLT spectroscopy of the giant Ly-alpha nebulae associated with three z~2.5 radio galaxies
• Illuminating gas in-/outflows in the MUSE deepest fields: discovery of Ly-alpha nebulae around forming galaxies at z~3.3
• Inhomogeneous Reionization Models in Cosmological Hydrodynamical Simulations
• The MUSE Ultra Deep Field (MUDF). I. Discovery of a group of Ly$\alpha$ nebulae associated with a bright $z\approx 3.23$ quasar pair
• Broadband Intensity Tomography: Spectral Tagging of the Cosmic UV Background
• Stacking the Cosmic Web in Fluorescent Lyman alpha Emission with MUSE
• ALMA observations of Lyman-alpha Blob 1: halo sub-structure illuminated from within
• A Faint Flux-Limited Lyman Alpha Emitter Sample at $z\sim 0.3$
• Emission from the circumgalactic medium: from cosmological zoom-in simulations to multiwavelength observables
• Spectroscopy of 7 Radio-Loud QSOs at 2<z<6: Giant Lyman-alpha Nebulae Accreting onto Host Galaxies
• Detecting the Cosmic Web: Lyα Emission from Simulated Filaments at z=3
• Integral Field Spectroscopy of two radio galaxies at z~2.3

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• Witnessing the onset of reionisation via Lyman-$\alpha$ emission at redshift 13
• The cold circumgalactic medium in emission: MgII halos in TNG50
• JADES: Primaeval Lyman-$\alpha$ emitting galaxies reveal early sites of reionisation out to redshift $z\sim 9$
• The cosmic web in Lyman-alpha emission
• Probing the Diffuse Lyman-alpha Emission on Cosmological Scales: Lyα Emission Intensity Mapping Using the Complete SDSS-IV eBOSS Survey
• Prospects for detecting cosmic filaments in Lyman-alpha emission across redshifts $z=2-5$
• Discovery of faint double-peak Halpha emission in the halo of low redshift galaxies