Simulating the epoch of Helium Reionization in photon-conserving semi-numerical code SCRIPT

Abstract

The reionization of the second electron of helium (HeII) leaves important imprints on the thermal and ionization state of the intergalactic medium (IGM). Observational evidence suggests that HeII reionization ended at $z\simeq 3$ due to ionizing photons emitted predominantly by quasars. We present efficient semi-numerical simulations of helium reionization in a $230{\mathrm{h}}^{-1}\mathrm{Mpc}$ box, that takes into account the spatial patchiness of reionization coupled with photoheating of the IGM. Dark matter haloes are assigned quasars using empirical measurements of the quasar luminosity function, assuming a universal quasar lifetime consistent with duty cycle values inferred from measurements of the quasar clustering. The ionizing photon field from quasars is then included in the semi-numerical Code for ReionIzation with PhoTon conservation (SCRIPT), which was originally developed for modeling hydrogen reionization. In this work, we make appropriate modifications to SCRIPT for modeling inhomogenous HeII reionization and the corresponding thermal history of the IGM is modelled via a subgrid prescription. Our model has three main free parameters i.e. the global clumping factor ${\mathcal{C}}_{HeIII}$, the temperature increase due to photoheating $T_{He}^{re}$ and the quasar spectral energy distribution (SED) index, ${\alpha }_{UV}$. Our fiducial model with ${\mathcal{C}}_{HeIII}=15.6$ and $T_{He}^{re}\sim 6000K$ gives reasonable values for the empirical measurements of the temperature density equation of state at these redshifts, assuming that quasars brighter than ${\mathrm{M}}_{1450}<-21$ and having ${\alpha }_{UV}=1.7$ contribute to HeII reionization. The efficiency of our code shows promising prospects for performing parameter estimation in future, for models of HeII reionization using observations of the Ly$\alpha$ forest.

arXiv comment34 pages, 12 Figures, Accepted for publication in JCAP

References in corpus (70)

• Planck 2015 results. XIII. Cosmological parameters
• Stable clustering, the halo model and nonlinear cosmological power spectra
• An analytic model for the spatial clustering of dark matter haloes
• Equation of State of the Photoionized Intergalactic Medium
• The Rest-Frame Extreme Ultraviolet Spectral Properties of QSOs
• Reionization of the Inhomogeneous Universe
• Simulating cosmic structure formation with the GADGET-4 code
• The thermal history of the intergalactic medium
• Detection of Extended He II Reionization in the Temperature Evolution of the Intergalactic Medium
• The first ultraviolet quasar stacked spectrum at z=2.4 from WFC3
• Reionization of Hydrogen and Helium by Early Stars and Quasars
• HeII Reionization and its Effect on the IGM
• Keeping the Universe ionised: Photo-heating and the clumping factor of the high-redshift intergalactic medium
• Evolution of the AGN UV luminosity function from redshift 7.5
• A Cosmic UV/X-ray Background Model Update
• The clustering of intermediate redshift quasars as measured by the Baryon Oscillation Spectroscopic Survey
• The Thermal Memory of Reionization History
• A Composite Extreme Ultraviolet QSO Spectrum from the Far Ultraviolet Spectroscopic Explorer
• Consistent modelling of the meta-galactic UV background and the thermal/ionization history of the intergalactic medium
• Clustering of intermediate redshift quasars using the final SDSS III-BOSS sample
• The one-dimensional power spectrum from the SDSS DR14 Ly$\alpha$ forests
• A Measurement of Small Scale Structure in the 2.2 < z < 4.2 Lyman-alpha Forest
• The High-Redshift He II Gunn-Peterson Effect: Implications and Future Prospects
• Probing the thermal state of the intergalactic medium at $z>5$ with the transmission spikes in high-resolution Ly$\alpha$ forest spectra
• Gas Clumping in Self-Consistent Reionisation Models
• Early and Extended Helium Reionization Over More Than 600 Million Years of Cosmic Time
• The thermal history of the intergalactic medium down to redshift z=1.5: a new curvature measurement
• Self-Consistent Modeling of Reionization in Cosmological Hydrodynamical Simulations
• A consistent and robust measurement of the thermal state of the IGM at $2\le z\le 4$ from a large sample of Ly$\alpha$ forest spectra: Evidence for late and rapid HeII reionization
• The End of Helium Reionization at z~2.7 Inferred from Cosmic Variance in HST/COS HeII Lyman Alpha Absorption Spectra
• Intergalactic Helium Absorption in Cold Dark Matter Models
• Models of the Thermal Evolution of the Intergalactic Medium After Reionization
• On the intergalactic temperature-density relation
• Characterizing the Pressure Smoothing Scale of the Intergalactic Medium
• The History and Morphology of Helium Reionization
• The Epoch of Helium Reionization
• The imprint of inhomogeneous HeII reionization on the HI and HeII Ly-alpha forest
• Photo-heating and the fate of hard photons during the reionisation of HeII by quasars
• Studying the Lyman-$\alpha$ optical depth fluctuations at $z\sim 5.5$ using fast semi-numerical methods
• Clustering of quasars in a wide luminosity range at redshift 4 with Subaru Hyper Suprime-Cam wide field imaging
• Photon number conservation and the large-scale 21 cm power spectrum in semi-numerical models of reionization
• The Dark Energy Spectroscopic Instrument: One-dimensional power spectrum from first Lyman-$\alpha$ forest samples with Fast Fourier Transform
• Inhomogeneous Helium Reionization and the Equation of State of the Intergalactic Medium
• The Evolution of the HeII-Ionizing Background at Redshifts 2.3<z<3.8 Inferred from a Statistical Sample of 24 HST/COS HeII Ly$\alpha$ Absorption Spectra
• Constraints on QSO emissivity using H I and He II Lyman alpha forest
• Helium Reionization Simulations. II. Signatures of Quasar Activity on the IGM
• Inferring the Thermal History of the Intergalactic Medium from the Properties of the Hydrogen and Helium Lyman-alpha Forest
• Inhomogeneous HeII reionization in Hydrodynamic Simulations
• The impact of helium reionization on the structure of the intergalactic medium
• A Short Introduction to Reionization Physics
• Pressure Support vs. Thermal Broadening in the Lyman-alpha Forest II: Effects of the Equation of State on Transverse Structure
• Patchy He II reionization and the physical state of the IGM
• The Sources of Extreme Ultraviolet and Soft X-ray Backgrounds
• HST-COS Observations of AGNs. III. Spectral Constraints in the Lyman Continuum from Composite COS/G140L Data
• A self-consistent 3D model of fluctuations in the helium-ionizing background
• The Effect of Fluctuations on the Helium-Ionizing Background
• Probing the thermal history during reionization using a semi-numerical photon-conserving code SCRIPT
• Photon Number Conserving Models of H II Bubbles during Reionization
• New Evidence for Extended HeII Reionization at z>3.5 from HeII Lyman Alpha and Beta Transmission Spikes
• Probing large scale filaments with HI and ${}^3$HeII
• Helium Reionization Simulations. I. Modeling Quasars as Radiation Sources
• The influence of metagalactic ultra-violet background fluctuations on the high-redshift Ly$\alpha$ forest
• Fossil Ionized Bubbles Around Dead Quasars During Reionization
• Constraining the reionization and thermal history of the Universe using a semi-numerical photon-conserving code SCRIPT
• Semi-numeric simulations of helium reionization and the fluctuating radiation background
• Late Reheating of the IGM by Quasars: A Radiation Hydrodynamical Simulation of Helium II Reionization
• Probing the high-z IGM with the hyperfine transition of ${}^3$He${}^{+}$
• Efficient exploration of reionization parameters for the upcoming 21 cm observations using a photon conserving semi-numerical model SCRIPT
• HeII Ly$\alpha$ Transmission Spikes and Absorption Troughs in Eight High-resolution Spectra Probing the End of HeII Reionization
• The hyperfine transition of 3He+ as a probe of the intergalactic medium

Cited by in corpus (1)

• Measuring photo-ionization rate and mean free path of HeII ionizing photons at $2.5\le z\le 3.6$: Evidence for late and rapid HeII reionization Part-II