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Enlightening our understanding of the first galaxies responsible for driving reionisation requires detecting the 21-cm signal from neutral hydrogen. Interpreting the wealth of information embedded in this signal requires Bayesian inference.…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-22 Bradley Greig , David Prelogović , Yuxiang Qin , Yuan-Sen Ting , Andrei Mesinger

Parameter estimation for gravitational-wave signals is computationally demanding due to the high dimensionality of the parameter space and the cost of repeated waveform generation in traditional Bayesian inference. These analyses require on…

General Relativity and Quantum Cosmology · Physics 2026-03-30 Sama Al-Shammari , Alexandre Göttel , Masaki Iwaya , Vivien Raymond

The ionisation structure of the Intergalactic Medium (IGM) during reionisation is sensitive to the unknown galaxy formation physics that prevailed at that time. This structure introduces non-Gaussian statistics into the redshifted 21 cm…

Cosmology and Nongalactic Astrophysics · Physics 2015-01-20 Stuart Wyithe , Paul M. Geil , Hansik Kim

Large-scale reionization simulations are described which combine the results of cosmological N-body simulations that model the evolving density and velocity fields and identify the galactic halo sources, with ray-tracing radiative transfer…

We quantify the presence of Ly\alpha\ damping wing absorption from a partially-neutral intergalactic medium (IGM) in the spectrum of the $z=7.08$ QSO, ULASJ1120+0641. Using a Bayesian framework, we simultaneously account for uncertainties…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-01 Bradley Greig , Andrei Mesinger , Zoltán Haiman , Robert A. Simcoe

We use synthetic sightlines drawn through snapshots of the Technicolor Dawn simulations to explore how the statistics of neutral oxygen OI absorbers respond to hydrogen reionization. The ionization state of the circumgalactic medium (CGM)…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-26 Caitlin Doughty , Kristian Finlator

We discuss constraints on cosmic reionisation and their implications on a cosmic SFR density $\rho_\mathrm{SFR}$ model; we study the influence of key-parameters such as the clumping factor of ionised hydrogen in the intergalactic medium…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-29 Adélie Gorce , Marian Douspis , Nabila Aghanim , Mathieu Langer

In a semi-numerical model of reionization, the evolution of ionization fraction is simulated approximately by the ionizing photon to baryon ratio criterion. In this paper we incorporate a semi-analytical model of galaxy formation based on…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Jie Zhou , Qi Guo , Gaochao Liu , Bin Yue , Yidong Xu , Xuelei Chen

We investigate the 21-cm signature that may arise from the intergalactic medium (IGM) prior to the epoch of full reionization (z>5). In scenarios in which the IGM is reionized by discrete sources of photoionizing radiation, the neutral gas…

Astrophysics · Physics 2009-10-28 Piero Madau , Avery Meiksin , Martin J. Rees

Given that the reionization history of cosmic hydrogen is yet to be stringently constrained, it is worth checking the prospects of doing so using physically motivated models and available observational data. For this purpose, we use an…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-04 Barun Maity , Tirthankar Roy Choudhury

Observations of high-redshift quasars show that the IGM must have been reionized at some redshift $z>5$. If a source of radiation could be observed at the rest-frame Lya wavelength, at a sufficiently high redshift where some of the IGM in…

Astrophysics · Physics 2009-09-28 Jordi Miralda-Escude

We calculate the cosmic microwave background (CMB) bispectrum due to inhomogeneous reionization. We calculate all the terms that can contribute to the bispectrum that are products of first order terms on all scales in conformal Newtonian…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Rishi Khatri , Benjamin D. Wandelt

We present a framework that for the first time allows Bayesian model comparison to be performed for field-level inference of cosmological models. We achieve this by taking a simulation-based inference (SBI) approach using neural likelihood…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-15 A. Spurio Mancini , K. Lin , J. D. McEwen

We investigate the constraints on the reionization history of the Universe from a joint analysis of the cosmic microwave background and neutral hydrogen fraction data. The $\tanh$ parametrization and principal component analysis methods are…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-27 Wei-Ming Dai , Yin-Zhe Ma , Zong-Kuan Guo , Rong-Gen Cai

Using hydrodynamical simulations coupled to a radiative transfer code, we study the additional heating effects in the intergalactic medium (IGM) produced by $z\sim 6$ quasars in their near-zones. If helium is predominantly in HeII to begin…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-13 Hamsa Padmanabhan , T. Roy Choudhury , R. Srianand

A possible explanation of the present discrepancy between the abundance of galactic subhaloes predicted by N-Body simulations with those observed in the Local Group is presented. We study the impact of an early reionization on the baryonic…

Astrophysics · Physics 2007-05-23 Andrea V. Maccio' , Ben Moore , Joachim Stadel , Doug Potter

Many scientific models are composed of multiple discrete components, and scientists often make heuristic decisions about which components to include. Bayesian inference provides a mathematical framework for systematically selecting model…

Machine Learning · Computer Science 2024-05-31 Cornelius Schröder , Jakob H. Macke

We develop and apply a new framework for reconstructing the ionization history during the epoch of recombination with combinations of cosmic microwave background (CMB), baryon acoustic oscillation (BAO) and supernova data. We find a wide…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-15 Gabriel P. Lynch , Lloyd Knox , Jens Chluba

The 21cm line from the spin-flip transition of neutral hydrogen (HI) provides a unique window into the Epoch of Reionization (EoR), the final phase transition of our Universe. The Square Kilometre Array (SKA) enables precise measurements of…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-09 Yannic Pietschke , Caroline Heneka , Tom Schlenker , Ayodele Ore , Benedikt Schosser

Measurements of the intergalactic medium (IGM) temperature provide a potentially powerful constraint on the reionisation history due to the thermal imprint left by the photo-ionisation of neutral hydrogen. However, until recently IGM…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Sudhir Raskutti , James S. Bolton , J. Stuart B. Wyithe , George D. Becker
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