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The incorporation of radiative transfer effects into cosmological hydrodynamical simulations is essential for understanding how the intergalactic medium (IGM) makes the transition from a neutral medium to one that is almost fully ionized.…

Astrophysics · Physics 2009-11-06 Aaron Sokasian , Tom Abel , Lars E. Hernquist

Observations of high-redshift Ly-alpha sources are a major tool for studying the high-redshift Universe. We discuss the effect of the reionizing intergalactic medium on the observability of Ly-alpha sources based on large simulations of…

Astrophysics · Physics 2009-11-13 Ilian T. Iliev , Paul R. Shapiro , Patrick McDonald , Garrelt Mellema , Ue-Li Pen

Cosmic reionization holds the key to understand structure formation in the Universe, and can inform us about the properties of the first sources, as their star formation efficiency and escape fraction of ionizing photons. By combining the…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-07 Sourav Mitra , T. Roy Choudhury , Andrea Ferrara

We study the luminosity functions of high-redshift galaxies in detailed hydrodynamic simulations of cosmic reionization, which are designed to reproduce the evolution of the Lyman-alpha forest between z=5 and z=6. We find that the…

Astrophysics · Physics 2010-11-11 A. Gayler Harford , Nickolay Y. Gnedin

In this chapter we provide an overview of the current status of the simulations and modelling of the Cosmic Dawn and Epoch of Reionization. We discuss the modelling requirements as dictated by the characteristic scales of the problem and…

Cosmology and Nongalactic Astrophysics · Physics 2015-01-20 Ilian T. Iliev , Mario G. Santos , Andrei Mesinger , Suman Majumdar , Garrelt Mellema

We study the two-dimensional topology of the 21-cm differential brightness temperature for two hydrodynamic radiative transfer simulations and two semi-numerical models. In each model, we calculate the two dimensional genus curve for the…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-13 Yougang Wang , Changbom Park , Yidong Xu , Xuelei Chen , Juhan Kim

In the coming decade, low-frequency radio arrays will begin to probe the epoch of reionization via the redshifted 21-cm hydrogen line. Successful interpretation of these observations will require effective statistical techniques for…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Vera Gluscevic , Rennan Barkana

We present a new hybrid code for large volume, high resolution simulations of cosmic reionization, which utilizes a N-body algorithm for dark matter, physically motivated prescriptions for baryons and star formation, and an adaptive ray…

Astrophysics · Physics 2009-11-11 Hy Trac , Renyue Cen

We consider cosmological models with a power spectrum of perturbations featuring an enhanced amplitude on dwarf galaxy scales (with a "bump" or a "tilt"). Early formation of a large number of galaxies in such models, compared to the…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-27 O. R. Skorikov , S. V. Pilipenko , M. V. Tkachev

Previous studies have noted difficulties in modeling the highest opacities of the $z>5.5$ Ly$\alpha$ forest, epitomized by the extreme Ly$\alpha$ trough observed towards quasar ULAS J0148+0600. One possibility is that the most opaque…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-15 Fahad Nasir , Anson D'Aloisio

In this paper, we present the formalism of simulating Lyman-$\alpha$ emission and polarization around reionization ($z$ = 8) from a plane-parallel ionization front. We accomplish this by using a Monte Carlo method to simulate the production…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-31 Yuanyuan Yang , Emily Koivu , Chenxiao Zeng , Heyang Long , Christopher M. Hirata

Conventional wisdom was that thermal relics from the epoch of reionization (EOR) would vanish swiftly. Recently, however, it was shown that these relics can survive to lower redshifts ($z \sim 2$) than previously thought, due to gas at mean…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-05 Paulo Montero-Camacho , Yi Mao

Reducing the power on small scales relative to the `standard' LCDM model alleviates a number of possible discrepancies with observations, and is favored by the recent analysis of WMAP plus galaxy and Lyman-alpha forest data. Here, we…

Astrophysics · Physics 2008-11-26 Rachel S. Somerville , James S. Bullock , Mario Livio

We use the photon flux and absorption tracer algorithm presented in Katz et al.~2018, to characterise the contribution of haloes of different mass and stars of different age and metallicity to the reionization of the Universe. We employ a…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-05 Harley Katz , Taysun Kimm , Martin G. Haehnelt , Debora Sijacki , Joakim Rosdahl , Jeremy Blaizot

Studying the cosmic dawn and the epoch of reionization through the redshifted 21 cm line are among the major science goals of the SKA1. Their significance lies in the fact that they are closely related to the very first stars in the…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-23 T. Roy Choudhury , Kanan Datta , Suman Majumdar , Raghunath Ghara , Aseem Paranjape , Rajesh Mondal , Somnath Bharadwaj , Saumyadip Samui

Understanding the epoch of reionization and the properties of the first galaxies represents an important goal for modern cosmology. The structure of reionization, and hence the observed power spectrum of redshifted 21cm fluctuations are…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Han-Seek Kim , J. Stuart B. Wyithe , Sudhir Raskutti , C. G. Lacey , J. C. Helly

The epoch of reionization is one of the least known chapters in the evolutionary history of the Universe. This thesis investigates two major approaches to unveil the reionization history of the Universe using HI 21-cm maps.The most…

Cosmology and Nongalactic Astrophysics · Physics 2009-06-04 Kanan K. Datta

Intensity mapping of the 21cm signal of neutral hydrogen will yield exciting insights into the Epoch of Reionisation and the nature of the first galaxies. However, the large amount of data that will be generated by the next generation of…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-15 Adélie Gorce , Anne Hutter , Jonathan R. Pritchard

The simple assumption of an instantaneous reionization of the Universe may bias estimates of cosmological parameters. In this paper a model-independent principal component method for the reionization history is applied to give constraints…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-21 Wei-Ming Dai , Zong-Kuan Guo , Rong-Gen Cai

Observations of the high-redshift Universe with the 21 cm hyperfine line of neutral hydrogen promise to open an entirely new window onto the early phases of cosmic structure formation. Here we review the physics of the 21 cm transition,…

Astrophysics · Physics 2009-11-11 Steven Furlanetto , S. Peng Oh , Frank Briggs