The Impact of The IGM on High-Redshift Lyman Alpha Emission Lines

Abstract

We calculate the impact of the intergalactic medium (IGM) on the observed Lyman alpha lines (hereafter Lya) emitted by galaxies in an ionised IGM at z>4. Our model accounts for gas clumping in the IGM and for the fact that high-redshift galaxies reside in overdense regions, which causes the velocity field of the IGM to depart from the Hubble flow. The observed shape of the Lya line varies widely, with dependence on the intrinsic width and systemic velocity of the line, a galaxies star formation rate and the local extra-galactic UV-background. For large star formation rates and levels of the UV-background, absorption in the IGM does not result in a Lya line that is asymmetric as is common among known high-redshift Lya emitters. For models in which the lines do show the observed strong asymmetry, the IGM typically transmits only 10-30% of the Lya flux. The increase in the ionising background that accompanied the completion of reionisation barely increased the IGM transmission, which suggests that LAEs of comparable luminosity should not appear to be significantly dimmer prior to overlap. In this light, we briefly discuss the potential of Lya emitters as a probe into the epoch of reionisation.

14 pages, 8 figures, MNRAS in press, minor changes, references added, some typos fixed

References in corpus (12)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• The End of the Reionization Epoch Probed by Ly-alpha Emitters at z=6.5 in the Subaru Deep Field
• The morphology of HII regions during reionization
• Formation of z ~ 6 quasars from hierarchical galaxy mergers
• A galaxy at a redshift z = 6.96
• Escape fraction of ionizing photons from galaxies at z=0--6
• The GLARE Survey II. Faint z=6 Ly-alpha Line Emitters in the HUDF
• The correlation between the distribution of galaxies and 21cm emission at high redshifts
• Lyman-alpha emission galaxies at a redshift of z = 5.7 in the FORS Deep Field
• The Wide Field Imager Lyman-Alpha Search (WFILAS) for Galaxies at Redshift ~5.7: II. Survey Design and Sample Analysis
• Lyman Alpha Constraints on Very Low Luminosity AGN
• An on-going multi-wavelength survey of Ly-alpha emitters at redshifts z = 2 - 8

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• Accelerated Evolution of Ly$\alpha$ Luminosity Function at $\text{z}\gtrsim 7$ Revealed by the Subaru Ultra-Deep Survey for Ly$\alpha$ Emitters at $\text{z}=7.3$
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• Probing Reionization with the 21 cm-Galaxy Cross Power Spectrum
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• The THESAN project: Lyman-alpha emission and transmission during the Epoch of Reionization
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• A VLT/FORS2 view at $z\sim 6$: Lyman-$\alpha$ emitter fraction and galaxy physical properties at the edge of the epoch of cosmic reionization
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• VIMOS-VLT spectroscopy of the giant Ly-alpha nebulae associated with three z~2.5 radio galaxies
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• The Polarization of Scattered Lyman Alpha Radiation Around High-Redshift Galaxies
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• Modeling $237$ Lyman-$\alpha$ spectra of the MUSE-Wide survey
• Modelling the observed luminosity function and clustering evolution of Lyman-$\alpha$ emitters: growing evidence for late reionization
• Lyman-$\alpha$ as a tracer of cosmic reionisation in the SPHINX radiation-hydrodynamics cosmological simulation
• Lyman Alpha Driven Outflows Around Star Forming Galaxies
• Lyman-alpha radiation hydrodynamics of galactic winds before cosmic reionization
• Quasar H II Regions During Cosmic Reionization
• Very Massive Stars in High-Redshift Galaxies
• Crucial Factors for Lyα Transmission in the Reionizing Intergalactic Medium: Infall Motion, HII Bubble Size, and Self-shielded Systems
• The reanalysis of spectra of GRB 080913 to estimate the neutral fraction of the IGM at a redshift of 6.7
• Dark-ages Reionization and Galaxy Formation Simulation XX. The Ly$\alpha$ IGM transmission properties and environment of bright galaxies during the Epoch of Reionization
• Effect of Intergalactic Medium on the Observability of Lyman Alpha Emitters during Cosmic Reionization
• Lyman Alpha and MgII as Probes of Galaxies and their Environments
• Narrow-band surveys for very high redshift Lyman-alpha emitters
• Revisiting the Gas Kinematics in SSA22 Lyman-$\alpha$ Blob 1 with Radiative Transfer Modeling in a Multiphase, Clumpy Medium
• Clustering and lifetime of Lyman Alpha Emitters in the Epoch of Reionization
• Continuum Emission by Cooling Clouds
• Early Results from GLASS-JWST XXIII: The transmission of Lyman-alpha from UV-faint z ~ 3-6 galaxies
• The THESAN project: Lyman-alpha emitter luminosity function calibration
• Constraints on the $z\sim 6-13$ intergalactic medium from JWST spectroscopy of Lyman-alpha damping wings in galaxies
• Catch Me if You Can: Biased Distribution of Ly$\alpha$-emitting Galaxies according to the Viewing Direction
• Dark Matter Annihilation in the Circumgalactic Medium at High Redshifts
• Estimating the Feasibility of 21cm-Ly$\alpha$ Synergies using the Hydrogen Epoch of Reionization Array
• HETDEX Public Source Catalog 1 -- Stacking 50K Lyman Alpha Emitters
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• Lyman Alpha line properties at $z\simeq 3.78$ and their environmental dependence: a case study around a massive proto-cluster
• Explaining JWST star formation history at $z\sim 17$ by modifying $\Lambda$CDM
• Observations of Ly$\alpha$ Emitters at High Redshift
• The miniJPAS Survey: Detection of double-core Lyα morphology of two high-redshift (z>3) QSOs
• SEURAT: SPH scheme extended with ultraviolet line radiative transfer
• Lyman-$\alpha$ Emitting Galaxies (LAEs) at Cosmic Dawn: Implications and Predictions
• The Effects of Dark Matter Annihilation and Dark Matter-Baryon Velocity Offsets at Cosmic Dawn
• Modelling the gas kinematics of an atypical Lyman-alpha emitting compact dwarf galaxy
• Far-infrared observations of dust in Ly$\alpha$ emitters at z=2-6