The b Distribution of the Lya Forest: Probing Cosmology and the Intergalactic Medium

Abstract

We investigate a method to determine the temperature-density relation of the intergalactic medium (IGM) at z~2-4 using quasar absorption line systems. Using a simple model combined with numerical simulations we show that there is a lower cutoff in the distribution of column density (NHI) and line width (b parameter). The location of this cutoff can be used to determine the temperature-density relation (under certain conditions). We describe and test an algorithm to do this. The method works as long as the amplitude of fluctuations on these scales (~100 kpc) is sufficiently large. Models with less power can mimic higher temperatures. A preliminary application is made to data from two quasar lines-of-sight, and we determine an upper limit to the temperature of the IGM. Finally, we examine the full distribution of b-parameters and show that this is completely specified by just two parameters: the temperature of the gas and the amplitude of the power spectrum. Using the temperature upper limit measured with the NHI-b cutoff method, we derive an upper limit to the amplitude of the power spectrum.

17 pages, 11 figures, submitted to ApJ

References in corpus (4)

• The Evolution of the Effective Equation of State of the IGM
• Compton Heating of the Intergalactic Medium by the Hard X-ray Background
• Hydrodynamical Simulations of the Lyman Alpha Forest: Model Comparisons
• KECK HIRES Spectroscopy of APM 08279+5255

Cited by in corpus (62)

• In the Beginning: The First Sources of Light and the Reionization of the Universe
• A New Calculation of the Ionizing Background Spectrum and the Effects of HeII Reionization
• Towards a Precise Measurement of Matter Clustering: Lyman-alpha Forest Data at Redshifts 2-4
• The thermal history of the intergalactic medium
• Simulations of Pregalactic Structure Formation with Radiative Feedback
• The Physics of the Intergalactic Medium
• The First Cosmic Structures and their Effects
• The Reionization of the Universe by the First Stars and Quasars
• The Gaseous Environment of High-z Galaxies: Precision Measurements of Neutral Hydrogen in the Circumgalactic Medium of z ~ 2-3 Galaxies in the Keck Baryonic Structure Survey
• The Observed Probability Distribution Function, Power Spectrum, and Correlation Function of the Transmitted Flux in the Lyman-alpha Forest
• Model-independent insights into the nature of the Lyman-alpha forest and the distribution of matter in the universe
• The Thermal Memory of Reionization History
• The Lyman-alpha forest opacity and the metagalactic hydrogen ionization rate at z~2-4
• The Lyman-$\alpha$ forest in optically-thin hydrodynamical simulations
• Consistent modelling of the meta-galactic UV background and the thermal/ionization history of the intergalactic medium
• Constraints on Warm Dark Matter from Cosmological Reionization
• 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
• Explaining the entropy excess in clusters and groups of galaxies without additional heating
• The Lyman-Alpha Forest at 1.5 < z < 4
• The Local Lyman-alpha Forest. II: Distribution of HI Absorbers, Doppler Widths, and Baryon Content
• The effects of UV background correlations on LyA forest flux statistics
• The photoheating of the intergalactic medium in synthesis models of the UV background
• The Temperature-Density Relation in the Intergalactic Medium at Redshift <z>=2.4
• A consistent determination of the temperature of the intergalactic medium at redshift z=2.4
• Cosmological parameters sigma_8, the baryon density, and the UV background intensity from a calibrated measurement of H I Lyman-alpha absorption at z = 1.9
• Characterizing the Pressure Smoothing Scale of the Intergalactic Medium
• Temperature fluctuations in the intergalactic medium
• A New Measurement of the Temperature Density Relation of the IGM From Voigt Profile Fitting
• The Type IIn SN 1995G: Interaction with the CSM
• The imprint of inhomogeneous HeII reionization on the HI and HeII Ly-alpha forest
• Detection of He II reionization in the SDSS quasar sample
• The Lyman-alpha forest in a blazar-heated Universe
• Environments of interacting transients: Impostors and type IIn supernovae
• The growth of structure in the intergalactic medium
• A Concordance Model of the Lyman-alpha Forest at z = 1.95
• Semi analytic approach to understanding the distribution of neutral hydrogen in the universe: Comparison of simulations with observations
• A New Precision Measurement of the Small-Scale Line-of-Sight Power Spectrum of the Ly$\alpha$ Forest
• Simulating the X-ray Forest
• Radiative transfer through the Intergalactic Medium
• The evolution of the physical state of the IGM
• A New Method to Directly Measure the Jeans Scale of the Intergalactic Medium Using Close Quasar Pairs
• Hydrodynamical simulations of the Lyman-Alpha forest: data comparisons
• Measurement of the small-scale structure of the intergalactic medium using close quasar pairs
• 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
• The X-ray surface brightness distribution from diffuse gas
• Modelling the IGM and the Lyalpha forest at high redshift from the dark matter distribution
• The impact of helium reionization on the structure of the intergalactic medium
• The broadening of Lyman-alpha forest absorption lines
• Patchy He II reionization and the physical state of the IGM
• Metal Enrichment and Temperature of the Intergalactic Medium
• The QSO proximity effect at redshift <z>=2.6 with the FLO approach
• Beyond Lyman-alpha: Constraints and Consistency Tests from the Lyman-beta Forest
• High resolution spectroscopy of the three dimensional cosmic web with close QSO groups
• Lyman alpha Absorption Systems and the Intergalactic Medium
• The HeII Lyman alpha forest and the thermal state of the IGM
• Measuring the equation of state of the high-z intergalactic medium using curvature statistics
• Probing the HI Kinematics of the LMC: Toward Interpreting QAL Observations of Protogalactic Velocity Fields
• Improving IGM temperature constraints using wavelet analysis on high-redshift quasars
• Constraining the Temperature-Density Relation of the Inter-Galactic Medium from Analytically Modeling Lyman-alpha Forest Absorbers
• The effect of helium reionization on the Lyman-alpha forest hydrogen flux statistics
• Neural network emulator to constrain the high-$z$ IGM thermal state from Lyman-$\alpha$ forest flux auto-correlation function