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[abridged] The First Stars in the Universe form out of pristine primordial gas clouds that have been radiatively cooled to a few hundreds of degrees Kelvin either via molecular or atomic (Lyman-Alpha) hydrogen lines. This primordial mode of…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-11 M. Trenti , M. Stiavelli

We present a new, on-the-fly photon flux and absorption tracer algorithm designed to directly measure the contribution of different source populations to the metagalactic UV background and to the ionisation fraction of gas in the Universe.…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-06 Harley Katz , Taysun Kimm , Martin Haehnelt , Debora Sijacki , Joakim Rosdahl , Jeremy Blaizot

We use a semi-analytical model to study the impact of reionization, and the associated radiative feedback, on galaxy formation. Two feedback models have been considered: (i) a standard prescription, according to which star formation is…

Astrophysics · Physics 2009-11-13 R. Schneider , R. Salvaterra , T. Roy Choudhury , A. Ferrara , C. Burigana , L. A. Popa

High-resolution numerical simulations including feedback and aimed at calculating the escape fraction (fesc) of hydrogen-ionizing photons often assume stellar radiation based on single-stellar population synthesis models. However, strong…

Astrophysics of Galaxies · Physics 2020-09-30 Amy Secunda , Renyue Cen , Taysun Kimm , Ylva Gotberg , Selma E. de Mink

The UV escape fraction from high-redshift galaxies plays a key role in models of cosmic reionisation. Because it is currently not possible to deduce the escape fractions during the epoch of reionisation from observations, we have to rely on…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Jan-Pieter Paardekooper , Federico I. Pelupessy , Gabriel Altay , Chael Kruip

We present our prediction for the local 21 cm differential brightness temperature ($\delta T_{b}$) from a set of strongly clustered sources of Population III (Pop III) and II (Pop II) objects in the early Universe, by a numerical simulation…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Kyungjin Ahn , Hao Xu , Michael L. Norman , Marcelo A. Alvarez , John H. Wise

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 study the reionisation of the Universe by stellar sources using a numerical approach that combines fast 3D radiative transfer calculations with high resolution hydrodynamical simulations. Ionising fluxes for the sources are derived from…

Astrophysics · Physics 2009-11-07 Aaron Sokasian , Tom Abel , Lars Hernquist , Volker Springel

While most simulations of the epoch of reionization have focused on single-stellar populations in star-forming dwarf galaxies, products of binary evolution are expected to significantly contribute to emissions of hydrogen-ionizing photons.…

Astrophysics of Galaxies · Physics 2021-09-08 Elizabeth Berzin , Amy Secunda , Renyue Cen , Alexander Menegas , Ylva Götberg

Standard analyses of the reionization history of the universe from Planck cosmic microwave background (CMB) polarization measurements consider only the overall optical depth to electron scattering ($\tau$), and further assume a step-like…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-18 V Miranda , Adam Lidz , Chen He Heinrich , Wayne Hu

The first stars continue to elude modern telescopes, but much has been accomplished in observing the glow of the first galaxies. As detection capabilities improve we will eventually resolve these galaxies, but hopes of observing an…

Solar and Stellar Astrophysics · Physics 2015-06-24 T. M. Lawlor , T. R. Young , J. Teffs , J. MacDonald

A self-consistent formalism to jointly study cosmic reionization and thermal history of the IGM is presented. The model implements most of the relevant physics governing these processes, such as the inhomogeneous IGM density distribution,…

Astrophysics · Physics 2009-11-10 T. Roy Choudhury , A. Ferrara

Semi-numeric methods have made it possible to efficiently model the epoch of reionisation (EoR). While most implementations involve a reduction to a simple three-parameter model, we introduce a new mass-dependent ionising efficiency…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-12 Daegene Koh , John H. Wise

The first Pop III stars formed out of primordial, metal free gas, in minihalos at z>20, and kickstarted the cosmic processes of reionizaton and enrichment. While these stars are likely more massive than their enriched counterparts, the…

Astrophysics of Galaxies · Physics 2022-10-21 Mia Sauda Bovill , Massimo Stiavelli , Alessa Ibrahim Wiggins , Massimo Ricotti , Michele Trenti

A detection of the 21-cm signal power spectrum from the Epoch of Reionization is imminent, thanks to consistent advancements from telescopes such as LOFAR, MWA, and HERA, along with the development of SKA. In light of this progress, it is…

Using a reionization model simultaneously accounting for a number of experimental data sets, we investigate the nature and properties of reionization sources. Such model predicts that hydrogen reionization starts at z \approx 15, is…

Astrophysics · Physics 2009-11-13 T. Roy Choudhury , A. Ferrara

Recent data from the James Webb Space Telescope suggest that there are realistic prospects for detecting the earliest generation of stars at redshift ~20. These metal-poor, gaseous Population III (Pop III) stars are likely in the mass range…

Solar and Stellar Astrophysics · Physics 2023-05-03 Teeraparb Chantavat , Siri Chongchitnan , Joseph Silk

We present semi-analytic models of galactic outflows, constrained by available observations on high redshift star formation and reionization. Galactic outflows are modeled in a manner akin to models of stellar wind blown bubbles. Large…

Astrophysics · Physics 2009-11-13 Saumyadip Samui , Kandaswamy Subramanian , Raghunathan Srianand

The recent detection of the sky-averaged 21-cm cosmological signal indicates a stronger absorption than the maximum allowed value based on the standard model. One explanation for the required colder primordial gas is the energy transfer…

Astrophysics of Galaxies · Physics 2018-07-25 Shingo Hirano , Volker Bromm

We make use of new subgrid model of turbulent mixing to accurately follow the cosmological evolution of the first stars, the mixing of their supernova ejecta, and the impact on the chemical composition of the Galactic Halo. Using the…

Astrophysics of Galaxies · Physics 2017-01-04 Richard Sarmento , Evan Scannapieco , Liubin Pan
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