Photon number conservation and the large-scale 21 cm power spectrum in semi-numerical models of reionization

@article{Choudhury2019PhotonNC,
title={Photon number conservation and the large-scale 21 cm power spectrum in semi-numerical models of reionization},
author={Tirthankar Roy Choudhury and Aseem Paranjape},
journal={2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)},
year={2019},
pages={1-1}
}
• Published 2 July 2018
• Physics
• 2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)
Semi-numerical models of the reionization of neutral hydrogen (HI) based on the excursion set (ES) approach are known to violate photon number conservation at the few per cent level. In this work, we highlight a more severe, previously unrecognized shortcoming of ES models: the large-scale 21 cm power spectrum (equivalently, HI bias $b_{\mathrm{HI}})$is a relatively strong function of the spatial resolution used to generate ES ionization maps. We trace this problem to the fact that photon non…

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References

SHOWING 1-10 OF 55 REFERENCES
Photon number conserving models of H ii bubbles during reionization
• Physics
• 2016
Traditional excursion set based models of H II bubble growth during the epoch of reionization are known to violate photon number conservation, in the sense that the mass fraction in ionized bubbles
Fast Large-Scale Reionization Simulations
• Physics
• 2008
We present an efficient method to generate large simulations of the epoch of reionization without the need for a full three-dimensional radiative transfer code. Large dark-matter-only simulations are
Epoch of reionization 21 cm forecasting from MCMC-constrained semi-numerical models
• Physics
• 2017
The recent low value of Planck (2016) integrated optical depth to Thomson scattering suggests that the reionization occurred fairly suddenly, disfavoring extended reionization scenarios. This will
Fast large volume simulations of the 21-cm signal from the reionization and pre-reionization epochs
• Physics
• 2009
While limited to low spatial resolution, the next-generation low-frequency radio interferometers that target 21-cm observations during the era of reionization and prior will have instantaneous fields
An improved model of H ii bubbles during the epoch of reionization
• Physics
• 2014
The size distribution of ionized regions during the epoch of reionization -- a key ingredient in understanding the HI power spectrum observable by 21cm experiments -- can be modelled analytically
Inside-out or outside-in: the topology of reionization in the photon-starved regime suggested by Lyα forest data
• Physics
• 2009
We use a set of seminumerical simulations based on the Zel'dovich approximation, the friends-of-friends algorithm and excursion set formalism to generate reionization maps of high dynamic range with
The Growth of H II Regions During Reionization
• Physics
• 2004
Recently, there has been a great deal of interest in understanding the reionization of hydrogen in the intergalactic medium (IGM). One of the major outstanding questions is how this event proceeds on
21 cm signal from cosmic dawn - II. Imprints of the light-cone effects
• Physics
• 2015
Details of various unknown physical processes during the cosmic dawn and the epoch of reionization can be extracted from observations of the redshifted 21-cm signal. These observations, however, will
Characteristic scales during reionization
• Physics
• 2006
One of the key observables of the reionization era is the distribution of neutral and ionized gas. Recently, Furlanetto, Zaldarriaga and Hernquist developed a simple analytic model to describe the
Simulations and Analytic Calculations of Bubble Growth during Hydrogen Reionization
• Physics
• 2007
We present results from a large volume simulation of hydrogen reionization. We combine 3D radiative transfer calculations and an N-body simulation, describing structure formation in the intergalactic