On the intergalactic temperature–density relation

McQuinn, Matthew; Sanderbeck, Phoebe R. Upton

doi:10.1093/mnras/stv2675

Cited by 79 publications

(54 citation statements)

References 18 publications

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“…At z = 5 the temperature field in the inhomogeneous approach (third row left column panel) shows lingering signatures of the temperature fluctuations on ∼ 5 h −1 Mpc scales. In this run different regions of the Universe are reionized and heated at different times, and so they asymptote to the temperature set by the balance between photoheating and the adiabatic and Compton cooling governing the temperature-density relationship at different times (McQuinn & Upton Sanderbeck 2016). In this particular case we see that the high-density regions, which reionized at high redshift have had time to cool and show lower temperatures than the low-density regions, which were reionized much later (D'Aloisio et al 2015;Davies et al 2018a).…”

Section: Comparison Of Flash and Inhomogeneous Reionization Simulationsmentioning

confidence: 78%

Inhomogeneous reionization models in cosmological hydrodynamical simulations

Oñorbe

Davies

Lukić

et al. 2019

Monthly Notices of the Royal Astronomical Society

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In this work we present a new hybrid method to simulate the thermal effects of reionization in cosmological hydrodynamical simulations. The method improves upon the standard approach used in simulations of the intergalactic medium (IGM) and galaxy formation without a significant increase of the computational cost, thereby allowing for efficient exploration of the parameter space. The method uses a small set of phenomenological input parameters, and combines a seminumerical reionization model to solve for the topology of reionization with an approximate model of how reionization heats the IGM using the massively parallel Nyx hydrodynamics code which is specifically designed to solve for the structure of diffuse IGM gas. We have produced several medium-scale high-resolution simulations (2048 3 , L box = 40 Mpc h −1 ) with different instantaneous and inhomogeneous H reionization models that use this new methodology. We study the IGM thermal properties of these models and find that large scale temperature fluctuations extend well beyond the end of reionization. By analyzing the 1D flux power spectrum of these models, we find up to ∼ 50% differences in the large-scale properties (low modes, k 0.01 s km −1 ) of the post-reionization power spectrum as a result of the thermal fluctuations. We show that these differences could allow one to distinguish between different reionization scenarios with existing Lyα forest measurements. Finally, we explore the differences in the small-scale cut-off of the power spectrum finding that, for the same heat input, models show very good agreement provided that the reionization redshift of the instantaneous reionization model occurs at the midpoint of the inhomogeneous model.

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Section: Comparison Of Flash and Inhomogeneous Reionization Simulationsmentioning

confidence: 78%

Inhomogeneous reionization models in cosmological hydrodynamical simulations

Oñorbe

Davies

Lukić

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…It also shows the thermal history of the LateR (blue), MiddleR (magenta) and EarlyR (orange) simulations. In the upper left panel we plot the evolution of γ, which exhibits the expected convergence to a value close to ∼ 1.6 after all reionization events for all models, resulting from the balance of photoheating with adiabatic cooling (Hui & Gnedin 1997;McQuinn & Upton Sanderbeck 2016). The larger decrease of γ during He ii reionization in the EarlyR, MiddleR, and LateR runs seems to indicate a temperature increase more independent of density than in the HM12 run.…”

Section: The Ionization and Thermal History Of The Igmmentioning

confidence: 87%

Self-consistent Modeling of Reionization in Cosmological Hydrodynamical Simulations

Oñorbe

Hennawi

Lukić

2017

ApJ

124

191

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The ultraviolet background (UVB) emitted by quasars and galaxies governs the ionization and thermal state of the intergalactic medium (IGM), regulates the formation of high-redshift galaxies, and is thus a key quantity for modeling cosmic reionization. The vast majority of cosmological hydrodynamical simulations implement the UVB via a set of spatially uniform photoionization and photoheating rates derived from UVB synthesis models. We show that simulations using canonical UVB rates reionize and, perhaps more importantly, spuriously heat the IGM, much earlier z ∼ 15 than they should. This problem arises because at z > 6, where observational constraints are nonexistent, the UVB amplitude is far too high. We introduce a new methodology to remedy this issue, and we generate selfconsistent photoionization and photoheating rates to model any chosen reionization history. Following this approach, we run a suite of hydrodynamical simulations of different reionization scenarios and explore the impact of the timing of reionization and its concomitant heat injection on the the thermal state of the IGM. We present a comprehensive study of the pressure smoothing scale of IGM gas, illustrating its dependence on the details of both hydrogen and helium reionization, and argue that it plays a fundamental role in interpreting Lyman-α forest statistics and the thermal evolution of the IGM. The premature IGM heating we have uncovered implies that previous work has likely dramatically overestimated the impact of photoionization feedback on galaxy formation, which sets the minimum halo mass able to form stars at high redshifts. We make our new UVB photoionization and photoheating rates publicly available for use in future simulations.

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“…where ∆ b is the baryon overdensity and T 0 is the temperature of the IGM at mean density. We include thermal fluctuations of the IGM using the standard power-law scaling relation (Hui & Gnedin 1997;McQuinn & Upton Sanderbeck 2016),…”

Section: From the Cross-correlation Of Galaxies With Transmitted Fluxmentioning

confidence: 99%

The role of galaxies and AGN in reionizing the IGM – III. IGM–galaxy cross-correlations at z ∼ 6 from eight quasar fields with DEIMOS and MUSE

Meyer

Kakiichi

Bosman

et al. 2020

Monthly Notices of the Royal Astronomical Society

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We present improved results of the measurement of the correlation between galaxies and the intergalactic medium (IGM) transmission at the end of reionisation. We have gathered a sample of 13 spectroscopically confirmed Lyman-break galaxies (LBGs) and 21 Lyman-α emitters (LAEs) at angular separations 20 θ 10 (∼ 0.1 − 4 pMpc at z ∼ 6) from the sightlines to 8 background z 6 quasars. We report for the first time the detection of an excess of Lyman-α transmission spikes at ∼ 10 − 60 cMpc from LAEs (3.6σ) and LBGs (3.1σ). We interpret the data with an improved model of the galaxy-Lyman-α transmission and two-point cross-correlations which includes the enhanced photoionisation due to clustered faint sources, enhanced gas densities around the central bright objects and spatial variations of the mean free path. The observed LAE(LBG)-Lyman-α transmission spike two-point cross-correlation function (2PCCF) constrains the luminosity-averaged escape fraction of all galaxies contributing to reionisation to f esc M UV <−12 = 0.10 +0.17 −0.05 (0.18 +0.52 −0.06 ). We investigate if the 2PCCF measurement can determine whether bright or faint galaxies are the dominant contributors to reionisation. Our results show that a contribution from faint galaxies (M UV > −20 (2σ)) is necessary to reproduce the observed 2PCCF and that reionisation might be driven by different sub-populations around LBGs and LAEs at z ∼ 6.

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On the intergalactic temperature–density relation

Cited by 79 publications

References 18 publications

Inhomogeneous reionization models in cosmological hydrodynamical simulations

Inhomogeneous reionization models in cosmological hydrodynamical simulations

Self-consistent Modeling of Reionization in Cosmological Hydrodynamical Simulations

The role of galaxies and AGN in reionizing the IGM – III. IGM–galaxy cross-correlations at z ∼ 6 from eight quasar fields with DEIMOS and MUSE

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