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相关论文: Simulating Reionization: Character and Observabili…

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We present the first large-scale, full radiative transfer simulations of the reionization of the intergalactic medium in the presence of Lyman-limit systems (LLSs). To illustrate the impact of LLS opacity, possibly missed by previous…

宇宙学与河外天体物理 · 物理学 2016-02-04 Hemant Shukla , Garrelt Mellema , Ilian T. Iliev , Paul R. Shapiro

The propagation of cosmological ionization fronts (I-fronts) during reionization is strongly influenced by small-scale structure. Here we summarize our recent attemps to understand the effect of this small-scale structure. We present high…

The 21 cm emission of neutral hydrogen is the most promising probe of the epoch of reionization(EoR). In the next few years, the SKA pathfinders will provide statistical measurements of this signal. Numerical simulations predicting these…

天体物理学 · 物理学 2009-11-13 S. Baek , P. Di Matteo , B. Semelin , F. Combes , Y. Revaz

The 21-cm PDF (i.e., distribution of pixel brightness temperatures) is expected to be highly non-Gaussian during reionization and to provide important information on the distribution of density and ionization. We measure the 21-cm PDF as a…

宇宙学与河外天体物理 · 物理学 2015-05-13 Kazuhide Ichikawa , Rennan Barkana , Ilian T. Iliev , Garrelt Mellema , Paul Shapiro

Concurrent observations of Lyman continuum (LyC) and Lyman-alpha (Lya) emission escaping from star-forming systems at low redshift are essential to understanding the physics of reionization at high redshift (z >~ 6). Some have suggested…

天体物理学 · 物理学 2015-05-13 Stephan R. McCandliss

We have modelled the process of reionization of the IGM by photoionization by galaxies, in order to predict the epoch of reionization. We use a sophisticated semi-analytic model to track the formation of galaxies. Our study represents a…

天体物理学 · 物理学 2009-11-11 A. J. Benson , Naoshi Sugiyama , Adi Nusser , C. G. Lacey

Traditional large-scale models of reionization usually employ simple deterministic relations between halo mass and luminosity to predict how reionization proceeds. We here examine the impact on modelling reionization of using more detailed…

Observations of galaxy luminosity function at high redshifts typically focus on fields of view of limited sizes preferentially containing bright sources. These regions possibly are overdense and hence biased with respect to the globally…

宇宙学与河外天体物理 · 物理学 2015-05-19 Girish Kulkarni , T. Roy Choudhury

Using 3D radiative transfer calculations on the reionization of an inhomogeneous universe, QSO absorption line systems are simulated and they are compared with observations of Ly$\alpha$ continuum depression at high redshifts. By this…

天体物理学 · 物理学 2007-05-23 M. Umemura , T. Nakamoto , H. Susa

An important characteristic of cosmic hydrogen reionization is the growth of ionized gas bubbles surrounding early luminous objects. Ionized bubble sizes are beginning to be probed using Lyman-$\alpha$ emission from high-redshift galaxies,…

Cosmic reionization is thought to be primarily fueled by the first generations of galaxies. We examine their stellar and gaseous properties, focusing on the star formation rates and the escape of ionizing photons, as a function of halo…

星系天体物理 · 物理学 2016-12-14 Hao Xu , John H. Wise , Michael L. Norman , Kyungjin Ahn , Brian W. O'Shea

We have studied the IGM reionization process in its full cosmological context including structure evolution and a realistic galaxy population. We have used a combination of high-resolution N-body simulations (to describe the dark matter and…

天体物理学 · 物理学 2009-11-07 B. Ciardi , F. Stoehr , S. D. M. White

We use large-scale simulations to investigate the morphology of reionization during the final, overlap phase. Our method uses an efficient three-dimensional smoothing technique which takes into account the finite mean free path due to…

宇宙学与河外天体物理 · 物理学 2012-02-27 Marcelo A. Alvarez , Tom Abel

We present a detailed comparison of three different simulations of the epoch of reionization (EoR). The radiative transfer simulation (${\rm C}^2$-RAY) among them is our benchmark. Radiative transfer codes can produce realistic results, but…

宇宙学与河外天体物理 · 物理学 2014-08-07 Suman Majumdar , Garrelt Mellema , Kanan K. Datta , Hannes Jensen , T. Roy Choudhury , Somnath Bharadwaj , Martina M. Friedrich

The detection of Lyman-$\alpha$ emitting galaxies (LAEs) puts severe constraints on the reionization history. In this Paper we derive the properties of very high-$z$ LAEs predicted in the only two reionization scenarios shown in a previous…

We study the evolution of ionization fronts around the first proto-galaxies by using high resolution numerical cosmological (Lambda+CDM model) simulations and Monte Carlo radiative transfer methods. We present the numerical scheme in detail…

天体物理学 · 物理学 2009-10-31 B. Ciardi , A. Ferrara , S. Marri , G. Raimondo

Lyman-alpha (Ly{\alpha}) photons from ionizing sources and cooling radiation undergo a complex resonant scattering process that generates unique spectral signatures in high-redshift galaxies. We present a detailed Ly{\alpha} radiative…

The temporal evolution of the ionizing UV background radiation field at high redshift provides a probe of the evolution of the early star formation rate. By comparing the observed levels of absorption in the highest redshift quasar spectra…

天体物理学 · 物理学 2009-11-07 Renyue Cen , Patrick McDonald

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.…

天体物理学 · 物理学 2009-11-06 Aaron Sokasian , Tom Abel , Lars E. Hernquist

We consider the degree to which "21 cm tomography" of the high-redshift Universe can distinguish different ionization histories. Using a new analytic model for the size distribution of HII regions that associates these ionized bubbles with…

天体物理学 · 物理学 2009-09-29 Steven Furlanetto , Matias Zaldarriaga , Lars Hernquist