Improving IGM temperature constraints using wavelet analysis on high-redshift quasars

Abstract

The thermal state of the intergalactic medium (IGM) contains vital information about the epoch of reionization, one of the most transformative yet poorly understood periods in the young universe. This thermal state is encoded in the small-scale structure of Lyman-$\alpha$ (Ly$\alpha$) absorption in quasar spectra. The 1D flux power spectrum measures the average small-scale structure along quasar sightlines. At high redshifts, where the opacity is large, averaging mixes high signal-to-noise ratio transmission spikes with noisy absorption troughs. Wavelet amplitudes are an alternate statistic that maintains spatial information while quantifying fluctuations at the same spatial frequencies as the power spectrum, giving them the potential to more sensitively measure the small-scale structure. Previous Ly$\alpha$ forest studies using wavelet amplitude probability density functions (PDFs) used limited spatial frequencies and neglected strong correlations between PDF bins and across wavelets scales, resulting in sub-optimal and unreliable parameter inference. Here we present a novel method for performing statistical inference using wavelet amplitude PDFs that spans the full range of spatial frequencies probed by the power spectrum and that fully accounts for these correlations. We applied this procedure to realistic mock data drawn from a simple thermal model parameterized by the temperature at mean density, $T_0$, and find that wavelets deliver 1$\sigma$ constraints on $T_0$ that are on average 7% more sensitive at $z=5$ (12% at $z=6$) than those from the power spectrum. We consider the possibility of combing wavelet PDFs with the power, but find that this does not lead to improved sensitivity.

arXiv commentAccepted for publication in MNRAS, 22 Pages, 16 Figures

References in corpus (71)

• Constraining the Evolution of the Ionizing Background and the Epoch of Reionization with z ~ 6 Quasars II: A Sample of 19 Quasars
• Warm Dark Matter as a solution to the small scale crisis: new constraints from high redshift Lyman-alpha forest data
• Equation of State of the Photoionized Intergalactic Medium
• New Constraints on the free-streaming of warm dark matter from intermediate and small scale Lyman-$\alpha$ forest data
• The Lyman Alpha Forest in the Spectra of QSOs
• Evidence of patchy hydrogen reionization from an extreme Ly$\alpha$ trough below redshift six
• Probing the Universe with the Lyman-alpha Forest: I. Hydrodynamics of the Low Density IGM
• The thermal history of the intergalactic medium
• Detection of Extended He II Reionization in the Temperature Evolution of the Intergalactic Medium
• Nyx: A Massively Parallel AMR Code for Computational Cosmology
• Large Lyman-alpha opacity fluctuations and low CMB tau in models of late reionization with large islands of neutral hydrogen extending to z<5.5
• The Evolution of the Effective Equation of State of the IGM
• The Evolution of Optical Depth in the Ly-alpha Forest: Evidence Against Reionization at z~6
• The Thermal Memory of Reionization History
• The Lyman-$\alpha$ forest in optically-thin hydrodynamical simulations
• Lyman-alpha Forest Constraints on the Mass of Warm Dark Matter and the Shape of the Linear Power Spectrum
• Constraints on reionization from the thermal history of the intergalactic medium
• Constraints on neutrino masses from Lyman-alpha forest power spectrum with BOSS and XQ-100
• Long troughs in the Lyman-$\alpha$ forest below redshift 6 due to islands of neutral hydrogen
• A Measurement of the Temperature-Density Relation in the Intergalactic Medium Using a New Lyman-alpha Absorption Line Fitting Method
• New Constraints on IGM Thermal Evolution from the Lyα Forest Power Spectrum
• A Measurement of Small Scale Structure in the 2.2 < z < 4.2 Lyman-alpha Forest
• Constraints from the Lyman alpha forest power spectrum
• Possible evidence for an inverted temperature-density relation in the intergalactic medium from the flux distribution of the Lyman-alpha forest
• Revealing reionization with the thermal history of the intergalactic medium: new constraints from the Lyman-$\alpha$ flux power spectrum
• Large Fluctuations in the High-Redshift Metagalactic Ionizing Background
• Large fluctuations in the hydrogen-ionizing background and mean free path following the epoch of reionization
• Measuring the equation of state of the intergalactic medium
• Probing the thermal state of the intergalactic medium at $z>5$ with the transmission spikes in high-resolution Ly$\alpha$ forest spectra
• Improved measurements of the intergalactic medium temperature around quasars: possible evidence for the initial stages of He-II reionisation at z~6
• Observing the tail of reionization: neutral islands in the $z=5.5$ Lyman-$\alpha$ Forest
• Constraints on X-ray Emissions from the Reionization Era
• The photoheating of the intergalactic medium in synthesis models of the UV background
• 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
• A consistent determination of the temperature of the intergalactic medium at redshift z=2.4
• The Temperature-Density Relation in the Intergalactic Medium at Redshift <z>=2.4
• Broadening of QSO Lyman-alpha forest absorbers
• On the intergalactic temperature-density relation
• Cosmological and astrophysical constraints from the Lyman-alpha forest flux probability distribution function
• Cutoff in the Lyman-$\alpha$ forest power spectrum: warm IGM or warm dark matter?
• Characterizing the Pressure Smoothing Scale of the Intergalactic Medium
• Evidence for Large-Scale Fluctuations in the Metagalactic Ionizing Background Near Redshift Six
• IGM Constraints from the SDSS-III/BOSS DR9 Ly-alpha Forest Flux Probability Distribution Function
• 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
• Temperature fluctuations in the intergalactic medium
• A first direct measurement of the intergalactic medium temperature around a quasar at z=6
• A New Measurement of the Temperature Density Relation of the IGM From Voigt Profile Fitting
• The b Distribution of the Lya Forest: Probing Cosmology and the Intergalactic Medium
• Heating of the Intergalactic Medium by Hydrogen Reionization
• Bayesian emulator optimisation for cosmology: application to the Lyman-alpha forest
• Probing the thermal history of the Intergalactic Medium with Lyman-alpha absorption lines
• A New Precision Measurement of the Small-Scale Line-of-Sight Power Spectrum of the Ly$\alpha$ Forest
• Inferring the IGM thermal history during reionisation with the Lyman-$\alpha$ forest power spectrum at redshift $z\simeq 5$
• Measurement of the small-scale structure of the intergalactic medium using close quasar pairs
• The Signatures of Large-scale Temperature and Intensity Fluctuations in the Lyman-alpha Forest
• Quasar Ionization Front Lyα Emission in an Inhomogeneous Intergalactic Medium
• The Lyman alpha forest flux probability distribution at z>3
• Tightening Constraints from the Lyman Alpha Forest with the Flux Probability Distribution Function
• Inhomogeneous Reionization Models in Cosmological Hydrodynamical Simulations
• Constraining Reionization with the $z\sim 5-6$ Lyman-$\alpha$ Forest Power Spectrum: the Outlook after Planck
• A wavelet analysis of QSO spectra
• A new Measurement of the Intergalactic Temperature at $z\sim 2.55-2.95$
• Searching for fluctuations in the IGM temperature using the Lyman alpha forest
• On Modeling and Measuring the Temperature of the z~5 IGM
• He II Proximity Effect and the Lifetime of Quasars
• The Impact of Temperature Fluctuations on the Lyman-alpha Forest Power Spectrum
• Spectral Analysis of the Lyman-Alpha Forest Using Wavelets
• Probing the Statistics of the Temperature-Density Relation of the IGM
• Joint Bayesian Estimation of Quasar Continua and the Lyman-Alpha Forest Flux Probability Distribution Function

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• Inferring the Thermal History of the Intergalactic Medium from the Properties of the Hydrogen and Helium Lyman-alpha Forest
• Comparisons between fast algorithms for the continuous wavelet transform and applications in cosmology: the 1D case
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• Measuring the thermal and ionization state of the low-$z$ IGM using likelihood free inference
• Searching for dilaton fields in the Ly$\alpha$ forest
• Ly$\alpha$NNA: A Deep Learning Field-level Inference Machine for the Lyman-$\alpha$ Forest
• Neural network emulator to constrain the high-$z$ IGM thermal state from Lyman-$\alpha$ forest flux auto-correlation function