Lyman-alpha radiative transfer during the Epoch of Reionization: contribution to 21-cm signal fluctuations

Abstract

During the epoch of reionization, Ly-alpha photons emitted by the first stars can couple the neutral hydrogen spin temperature to the kinetic gas temperature, providing the opportunity to observe the gas in emission or absorption in the 21-cm line. Given the bright foregrounds, it is of prime importance to determine precisely the fluctuations signature of the signal, to be able to extract it by its correlation power. LICORICE is a Monte-Carlo radiative transfer code, coupled to the dynamics via an adaptative Tree-SPH code. We present here the Ly-alpha part of the implementation, and validate it through three classical tests. Contrary to previous works, we do not assume that P_alpha, the number of scatterings of Ly-alpha photons per atom per second, is proportional to the Ly-alpha background flux, but take into account the scatterings in the Ly-alpha line wings. The latter have the effect to steepen the radial profile of P_alpha around each source, and re-inforce the contrast of the fluctuations. In the particular geometry of cosmic filaments of baryonic matter, Ly-alpha photons are scattered out of the filament, and the large scale structure of P_alpha is significantly anisotropic. This could have strong implications for the possible detection of the 21-cm signal.

13 pages, 9 figures. To be published in A&A

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Cited by in corpus (37)

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• Cosmic Reionization and the 21-cm signal: Comparison between an analytical model and a simulation
• The simulated 21 cm signal during the epoch of reionization : full modeling of the Ly-alpha pumping
• High-redshift radio galaxies: a potential new source of 21-cm fluctuations
• The subtlety of Ly-a photons: changing the expected range of the 21-cm signal
• The Lyman-alpha signature of the first galaxies
• RASCAS: RAdiation SCattering in Astrophysical Simulations
• The Polarization of Scattered Lyman Alpha Radiation Around High-Redshift Galaxies
• Imaging the redshifted 21-cm pattern around the first sources during the cosmic dawn using the SKA
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• Lyman-$\alpha$ coupling and heating at Cosmic Dawn
• Redshift-space distortions in simulations of the 21-cm signal from the cosmic dawn
• Ly-alpha Radiative Transfer: Monte-Carlo Simulation of the Wouthuysen-Field Effect
• Detecting Early Galaxies Through Their 21-cm Signature
• Radiative Transfer Effect on Ultraviolet Pumping of the 21cm Line in the High Redshift Universe
• Probing the first galaxies with the SKA
• Radiation-induced large-scale structure during the reionization epoch: the autocorrelation function
• Can the 21 cm signal probe Population III and II star formation?
• A unified framework for 21cm tomography sample generation and parameter inference with Progressively Growing GANs
• The cosmic web in Lyman-alpha emission
• Ly-alpha Radiative Transfer: A Stokes Vector Approach to Ly-alpha Polarization
• pyC${}^2$Ray: A flexible and GPU-accelerated Radiative Transfer Framework for Simulating the Cosmic Epoch of Reionization
• Improved upper limits on the 21-cm signal power spectrum at $z=17.0$ and $z=20.3$ from an optimal field observed with NenuFAR
• Mapping discrete galaxies at cosmic dawn with 21-centimeter observations
• The Wouthuysen-Field effect in a clumpy intergalactic medium
• Analysing the Epoch of Reionization with three-point correlation functions and machine learning techniques
• Radiative transfer of Lyman-$\alpha$ photons at cosmic dawn with realistic gas physics
• Enabling Radiative Transfer on AMR grids in CRASH
• Lyman-alpha resonant-line radiative transfer in expanding media
• Scattering of Lyα Photons through the Reionizing Intergalactic Medium: I. Spectral Energy Distribution
• SEURAT: SPH scheme extended with ultraviolet line radiative transfer
• The signature of galaxy formation models in the power spectrum of the hydrogen 21cm line during reionization
• Influence of turbulence on Lyman-alpha scattering
• A Comprehensive Bayesian re-analysis of the SARAS2 data from the Epoch of Reionization