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Unveiling the thermal history of the intergalactic medium (IGM) at $4 \leq z \leq 5$ holds the potential to reveal early onset HeII reionization or lingering thermal fluctuations from HI reionization. We set out to reconstruct the IGM gas…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-10 Fahad Nasir , Prakash Gaikwad , Frederick B. Davies , James S. Bolton , Ewald Puchwein , Sarah E. I. Bosman

We explore the use of Deep Learning to infer physical quantities from the observable transmitted flux in the Lyman-alpha forest. We train a Neural Network using redshift z=3 outputs from cosmological hydrodynamic simulations and mock…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-07 Lawrence Huang , Rupert A. C. Croft , Hitesh Arora

The temperature of the low-density intergalactic medium (IGM) at high redshift is sensitive to the timing and nature of hydrogen and HeII reionization, and can be measured from Lyman-alpha forest absorption spectra. Since the memory of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Adam Lidz , Matthew Malloy

The filamentary network of intergalactic medium (IGM) gas that gives origin to the Lyman-alpha forest in the spectra of distant quasars encodes information on the physics of structure formation and the early thermodynamics of diffuse…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-20 Bruno Villasenor , Brant Robertson , Piero Madau , Evan Schneider

The temperature of the diffuse, photo-heated intergalactic medium (IGM) depends on its reionization history because the thermal time scales are long. The widths of the hydrogen Lyman-alpha absorption lines seen in the spectra of distant…

The temperature of the low-density intergalactic medium is set by the balance between adiabatic cooling resulting from the expansion of the universe, and photo-heating by the UV-background. We have analysed the Lyman-alpha forest of eleven…

The distribution of the absorption line broadening observed in the Ly$\alpha$ forest carries information about the temperature and widths of the filaments in the intergalactic medium (IGM). In this work, we present and test a new method for…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-04 Antonella Garzilli , Tom Theuns , Joop Schaye

We aim to construct a machine-learning approach that allows for a pixel-by-pixel reconstruction of the intergalactic medium (IGM) density field for various warm dark matter (WDM) models using the Lyman-alpha forest. With this regression…

We present a new investigation of the thermal history of the intergalactic medium (IGM) during and after reionization using the Lyman-$\alpha$ forest flux power spectrum at $4.0\lesssim z\lesssim5.2$. Using a sample of 15 high-resolution…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-27 Elisa Boera , George D. Becker , James S. Bolton , Fahad Nasir

The absorption by neutral hydrogen in the intergalactic medium (IGM) produces the Ly$\alpha$ forest in the spectra of quasars. The Ly$\alpha$ forest absorbers have a broad distribution of neutral hydrogen column density $N_{\rm HI}$ and…

Astrophysics of Galaxies · Physics 2023-04-05 Li Yang , Zheng Zheng , T. -S. Kim

We present a neural network emulator to constrain the thermal parameters of the intergalactic medium (IGM) at $\displaystyle{5.4}\le{z}\le{6.0}$ using the Lyman-$\displaystyle\alpha$ (Ly$\displaystyle\alpha$) forest flux auto-correlation…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-24 Zhenyu Jin , Molly Wolfson , Joseph F. Hennawi , Diego González-Hernández

We present new measurements of the temperature of the intergalactic medium (IGM) derived from the Lyman-alpha forest over 2.0 < z < 4.8. The small-scale structure in the forest of 61 high-resolution QSO spectra is quantified using a new…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 George D. Becker , James S. Bolton , Martin G. Haehnelt , Wallace L. W. Sargent

The reionization of helium is thought to occur at $2.5\lesssim z\lesssim4$, marking the last phase transition and final global heating event of the intergalactic medium (IGM). Since it is driven by rare quasars, helium reionization should…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-13 Saba Etezad-Razavi , Sarah E. I. Bosman , Frederick B. Davies

The temperature of the low-density intergalactic medium is set by the balance between adiabatic cooling resulting from the expansion of the universe, and photo-heating by the UV-background. A sudden injection of entropy from the…

Astrophysics · Physics 2007-05-23 Tom Theuns , Saleem Zaroubi , Tae-Sun Kim

We determine the thermal evolution of the intergalactic medium (IGM) over $3\, \mathrm{Gyr}$ of cosmic time $1.8<z<5.4$ by comparing measurements of the Ly{\alpha} forest power spectrum to a suite of $\sim70$ hydrodynamical simulations. We…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-13 Michael Walther , Jose Oñorbe , Joseph F. Hennawi , Zarija Lukić

In this article, the temperature-density relation of the intergalactic medium was studied in the region $1.6 \leq z < 2.0$ divided into two bins. For this purpose, the Ly-$\alpha$ forest decomposition into individual absorption profiles was…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-04 Tomáš Ondro , Rudolf Gális

Quasar spectra provide a unique opportunity to investigate the intergalactic medium at high redshifts. The spectral analysis of the Ly$\alpha$ forest allows us to constrain the effective equation of state of the intergalactic medium and its…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-02 K N Telikova , S A Balashev , P S Shternin

According to the photo-heating model of the intergalactic medium (IGM), He II reionization is expected to affect its thermal evolution. Evidence for additional energy injection into the IGM has been found at $3\lesssim z\lesssim4$, though…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Elisa Boera , Michael T. Murphy , George D. Becker , James S. Bolton

The intergalactic medium (IGM) acts like a calorimeter recording energy injection by cosmic structure formation, shocks and photoheating from stars and active galactic nuclei. It was recently proposed that spatially inhomogeneous…

Astrophysics of Galaxies · Physics 2022-03-14 A. Lamberts , E. Puchwein , C. Pfrommer , P. Chang , M. Shalaby , A. Broderick , P. Tiede , G. Rudie

We investigate the thermal history of the intergalactic medium (IGM) in the redshift interval z=1.7--3.2 by studying the small-scale fluctuations in the Lyman alpha forest transmitted flux. We apply a wavelet filtering technique to eighteen…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 A. Garzilli , J. S. Bolton , T. -S. Kim , S. Leach , M. Viel
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