The Signatures of Large-scale Temperature and Intensity Fluctuations in the Lyman-alpha Forest

Abstract

It appears inevitable that reionization processes would have produced large-scale temperature fluctuations in the intergalactic medium. Using toy temperature models and detailed heating histories from cosmological simulations of HeII reionization, we study the consequences of inhomogeneous heating for the Ly-alpha forest. The impact of temperature fluctuations in physically well-motivated models can be surprisingly subtle. In fact, we show that temperature fluctuations at the level predicted by our reionization simulations do not give rise to detectable signatures in the types of statistics that have been employed previously. However, because of the aliasing of small-scale density power to larger scale modes in the line-of-sight Ly-alpha forest power spectrum, earlier analyses were not sensitive to 3D modes with >~ 30 comoving Mpc wavelengths -- scales where temperature fluctuations are likely to be relatively largest. The ongoing Baryon Oscillation Spectroscopic Survey (BOSS) aims to measure the 3D power spectrum of the Ly-alpha forest, P_F, from a large sample of quasars in order to avoid this aliasing. We find that physically motivated temperature models can alter P_F at an order unity level at k <~ 0.1 comoving Mpc^{-1}, a magnitude that should be easily detectable with BOSS. Fluctuations in the intensity of the ultraviolet background can also alter P_F significantly. These signatures will make it possible for BOSS to study the thermal impact of HeII reionization at 2 < z < 3 and to constrain models for the sources of the ionizing background. Future spectroscopic surveys could extend this measurement to even higher redshifts, potentially detecting the thermal imprint of hydrogen reionization.

14 pages, 17 figures, plus 4 pages of Appendix, matches published version

References in corpus (17)

• An Observational Determination of the Bolometric Quasar Luminosity Function
• Detection of Extended He II Reionization in the Temperature Evolution of the Intergalactic Medium
• HeII Reionization and its Effect on the IGM
• A Direct Precision Measurement of the Intergalactic Lyman-alpha Opacity at 2<z<4.2
• Possible evidence for an inverted temperature-density relation in the intergalactic medium from the flux distribution of the Lyman-alpha forest
• An improved measurement of the flux distribution of the Ly-alpha forest in QSO absorption spectra: the effect of continuum fitting, metal contamination and noise properties
• Imprint of Inhomogeneous Hydrogen Reionization on the Temperature Distribution of the Intergalactic Medium
• The History and Morphology of Helium Reionization
• A Flat Photoionization Rate at 2<z<4.2: Evidence for a Stellar-Dominated UV Background and Against a Decline of Cosmic Star Formation Beyond z~3
• The Acoustic Peak in the Lyman Alpha Forest
• Inhomogeneous Helium Reionization and the Equation of State of the Intergalactic Medium
• Spectral shape of the UV ionizing background and HeII absorption at redshifts 1.8 < z < 2.9
• The evolution of the helium-ionizing background at z ~ 2-3
• The Implications of Gunn-Peterson Troughs in the HeII Lyman-alpha Forest
• Probing the Epoch of Reionization with the Lyman Alpha Forest at z~4-5
• Threshold Clustering Functions and Thermal Inhomogeneities in the Lyman-Alpha Forest
• Spatial Correlations in the Helium-Ionizing Background

Cited by in corpus (46)

• Observational Probes of Cosmic Acceleration
• Evidence of patchy hydrogen reionization from an extreme Ly$\alpha$ trough below redshift six
• The Evolution of the Intergalactic Medium
• New constraints on Lyman-α opacity with a sample of 62 quasars at z > 5.7
• The Lyman-$\alpha$ forest in optically-thin hydrodynamical simulations
• A Significantly Neutral Intergalactic Medium Around the Luminous z=7 Quasar J0252-0503
• Probing the thermal state of the intergalactic medium at $z>5$ with the transmission spikes in high-resolution Ly$\alpha$ forest spectra
• The photoheating of the intergalactic medium in synthesis models of the UV background
• The intergalactic medium thermal history at redshift z=1.7--3.2 from the Lyman alpha forest: a comparison of measurements using wavelets and the flux distribution
• On Estimating Lyman-alpha Forest Correlations between Multiple Sightlines
• Observational Requirements for Lyman-alpha Forest Tomographic Mapping of Large-Scale Structure at z ~ 2
• Scale-dependent bias in the BAO-scale intergalactic neutral hydrogen
• New approach for precise computation of Lyman-alpha forest power spectrum with hydrodynamical simulations
• Bias, redshift space distortions and primordial nongaussianity of nonlinear transformations: application to Lyman alpha forest
• VoIgt profile Parameter Estimation Routine (VIPER): H I photoionization rate at z<0.5
• Inferring the IGM thermal history during reionisation with the Lyman-$\alpha$ forest power spectrum at redshift $z\simeq 5$
• The Lyman alpha forest flux probability distribution at z>3
• Imprints of temperature fluctuations on the $z\sim 5$ Lyman-$\alpha$ forest: a view from radiation-hydrodynamic simulations of reionization
• Sample variance and Lyman-alpha forest transmission statistics
• Exploring the Thermal State of the Low-Density Intergalactic Medium at z=3 with an Ultra-High Signal-to-Noise QSO Spectrum
• On Modeling and Measuring the Temperature of the z~5 IGM
• Helium Reionization Simulations. II. Signatures of Quasar Activity on the IGM
• The observable 21cm signal from reionization may be perturbative
• Inhomogeneous HeII reionization in Hydrodynamic Simulations
• LyMAS: Predicting Large-Scale Lyman-alpha Forest Statistics from the Dark Matter Density Field
• The broadening of Lyman-alpha forest absorption lines
• Intensity mapping with neutral hydrogen and the Hidden Valley simulations
• Modeling the Lyman-alpha Forest in Collisionless Simulations
• The Concerted Impact of Galaxies and QSOs on the Ionization and Thermal State of the Intergalactic Medium
• The case against large intensity fluctuations in the z ~ 2.5 HeII Lyman-alpha forest
• Towards physics responsible for large-scale Lyman-$\alpha$ forest bias parameters
• The Ly$\alpha$ forest flux correlation function: a perturbation theory perspective
• Constraints on ionising photon production from the large-scale Lyman-alpha forest
• Helium Reionization Simulations. I. Modeling Quasars as Radiation Sources
• Time-dependent fluctuations in the metagalactic photoionization background
• UV Background Fluctuations and Three-Point Correlations in the Large Scale Clustering of the Lyman-alpha Forest
• Helium Reionization Simulations. III. The Helium Lyman-$\alpha$ Forest
• Estimates for the impact of Ultraviolet Background fluctuations on galaxy clustering measurements
• Possible evidence for a large-scale enhancement in the Lyman-$\alpha$ forest power spectrum at redshift $\text{z}\ge 4$
• The impact of temperature fluctuations on the large-scale clustering of the Ly$\alpha$ forest
• A measurement of the Lyman-beta forest power spectrum and its cross with the Lyman-alpha forest in X-Shooter XQ-100
• Improving IGM temperature constraints using wavelet analysis on high-redshift quasars
• Boosting Line Intensity Map Signal-to-Noise with the Ly-$\alpha$ Forest Cross-Correlation
• Probing Large Scale Ionizing Background Fluctuation with Lyman $\alpha$ Forest and Galaxy Cross-correlation at z=2.4
• Deep Forest: Neural Network reconstruction of intergalactic medium temperature
• Neural network emulator to constrain the high-$z$ IGM thermal state from Lyman-$\alpha$ forest flux auto-correlation function