Urchin: A Reverse Ray Tracer for Astrophysical Applications

Abstract

We describe URCHIN, a reverse ray tracing radiative transfer scheme optimised to model self-shielding from the post-reionisation ultraviolet (UV) background in cosmological simulations. The reverse ray tracing strategy provides several benefits over forward ray tracing codes including: (1) the preservation of adaptive density field resolution (2) completely uniform sampling of gas elements by rays; (3) the preservation of galilean invariance; (4) the ability to sample the UV background spectrum with hundreds of frequency bins; and (5) exact preservation of the input UV background spectrum and amplitude in optically thin gas. The implementation described here focuses on Smoothed Particle Hydrodynamics (SPH). However, the method can be applied to any density field representation in which resolution elements admit ray intersection tests and can be associated with optical depths. We characterise the errors in our implementation in stages beginning with comparison to known analytic solutions and ending with a realistic model of the z = 3 cosmological UV background incident onto a suite of spherically symmetric models of gaseous galactic halos.

17 pages, updated to match version published in MNRAS; 2013MNRAS.tmp.1731A

References in corpus (19)

• A luminous quasar at a redshift of z = 7.085
• The effect of photo-ionization on the cooling rates of enriched, astrophysical plasmas
• Observational constraints on Cosmic Reionization
• Chemical enrichment in cosmological, smoothed particle hydrodynamics simulations
• Massloss of galaxies due to a UV-background
• On the evolution of the HI column density distribution in cosmological simulations
• Column density distribution and cosmological mass density of neutral gas: Sloan Digital Sky Survey-III Data Release 9
• Damped Lyman Alpha Systems in Galaxy Formation Simulations
• Cosmological Radiative Transfer Codes Comparison Project I: The Static Density Field Tests
• A multiphysics and multiscale software environment for modeling astrophysical systems
• A radiative transfer scheme for cosmological reionization based on a local Eddington tensor
• Through Thick and Thin - HI Absorption in Cosmological Simulations
• TRAPHIC - Radiative Transfer for Smoothed Particle Hydrodynamics Simulations
• The impact of local stellar radiation on the HI column density distribution
• An implementation of radiative transfer in the cosmological simulation code GADGET
• SPHRAY: A Smoothed Particle Hydrodynamics Ray Tracer for Radiative Transfer
• Multi-frequency, thermally coupled radiative transfer with TRAPHIC: Method and tests
• A New Moment Method for Continuum Radiative Transfer in Cosmological Reionization
• Lyman Limit Systems in Cosmological Simulations

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