Modelling recombinations during cosmological reionization

Abstract

An ionization front expanding into a neutral medium can be slowed-down significantly by recombinations. In cosmological numerical simulations the recombination rate is often computed using a 'clumping factor', that takes into account that not all scales in the simulated density field are resolved. Here we demonstrate that using a single value of the clumping factor significantly overestimates the recombination rate, and how a local estimate of the clumping factor is both easy to compute, and gives significantly better numerical convergence. We argue that this lower value of the recombination rate is more relevant during the reionization process and hence that the importance of recombinations during reionization has been overestimated.

5 pages, 3 figures, accepted for publication in MNRAS Letters

References in corpus (8)

• The morphology of HII regions during reionization
• z~7-10 Galaxies in the HUDF and GOODS fields, and their UV Luminosity Functions
• Keeping the Universe ionised: Photo-heating and the clumping factor of the high-redshift intergalactic medium
• Radiative transfer simulations of cosmic reionization I: methodology and initial results
• A Population of Faint Extended Line Emitters and the Host Galaxies of Optically Thick QSO Absorption Systems
• Self-regulated reionization
• Minihalo photoevaporation during cosmic reionization: evaporation times and photon consumption rates
• The galaxies that reionized the Universe

Cited by in corpus (20)

• CANDELS: The Contribution of the Observed Galaxy Population to Cosmic Reionization
• Gas Clumping in Self-Consistent Reionisation Models
• Constraining the UV emissivity of AGN throughout cosmic time via X-ray surveys
• Direct Numerical Simulation of Reionization II: Recombinations, Clumping Factors, and the Photon Budget for Reionization
• Simulating the 21-cm signal from reionisation including non-linear ionisations and inhomogeneous recombinations
• The Hydrodynamic Feedback of Cosmic Reionization on Small-Scale Structures and Its Impact on Photon Consumption during the Epoch of Reionization
• The visibility of Lyman Alpha Emitters: constraining reionization, ionizing photons and dust
• The impact of inhomogeneous subgrid clumping on cosmic reionization
• Observational constraints on key-parameters of cosmic reionisation history
• Thermal constraints on the reionisation of hydrogen by population-II stellar sources
• Cosmic Reionization On Computers III. The Clumping Factor
• ARGOT: Accelerated radiative transfer on grids using oct-tree
• The impact of inhomogeneous subgrid clumping on cosmic reionization II: modelling stochasticity
• ARTIST: Fast radiative transfer for large-scale simulations of the epoch of reionisation
• Constraining the Contribution of Galaxies and Active Galactic Nuclei to Cosmic Reionization
• Helium Reionization Simulations. I. Modeling Quasars as Radiation Sources
• The impact and response of minihalos and the inter-halo medium on cosmic reionization
• Clumping factors of HII, HeII and HeIII
• Leaving the dark ages with AMIGA
• Streaming Velocity Effects on the Post-reionization 21 cm Baryon Acoustic Oscillation Signal