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相关论文: Topology and Sizes of HII Regions during Cosmic Re…

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Using Shapefinders, which are ratios of Minkowski functionals, we study the morphology of neutral hydrogen (HI) density fields, simulated using semi-numerical technique (inside-out), at various stages of reionization. Accompanying the…

宇宙学与河外天体物理 · 物理学 2018-09-21 Satadru Bag , Rajesh Mondal , Prakash Sarkar , Somnath Bharadwaj , Varun Sahni

The evolution of topology and morphology of ionized or neutral hydrogen during different stages of the Epoch of Reionization (EoR) have the potential to provide us a great amount of information about the properties of the ionizing sources…

宇宙学与河外天体物理 · 物理学 2022-11-23 Aadarsh Pathak , Satadru Bag , Saswata Dasgupta , Suman Majumdar , Rajesh Mondal , Mohd Kamran , Prakash Sarkar

A key physical quantity during reionization is the size of HII regions. Previous studies found a characteristic bubble size which increases rapidly during reionization, with apparent agreement between simulations and analytic excursion set…

宇宙学与河外天体物理 · 物理学 2016-10-07 Yin Lin , S. Peng Oh , Steven R. Furlanetto , P. M. Sutter

We introduce a novel technique, called "granulometry", to characterize and recover the mean size and the size distribution of HII regions from 21-cm tomography. The technique is easy to implement, but places the previously not very well…

It is possible that the properties of HII regions during reionization depend sensitively on many poorly constrained quantities (the nature of the ionizing sources, the clumpiness of the gas in the IGM, the degree to which photo-ionizing…

天体物理学 · 物理学 2008-11-26 Matthew McQuinn , Adam Lidz , Oliver Zahn , Suvendra Dutta , Lars Hernquist , Matias Zaldarriaga

We present the first large-scale radiative transfer simulations of cosmic reionization, in a simulation volume of (100/h Mpc)^3, while at the same time capturing the dwarf galaxies which are primarily responsible for reionization. We…

天体物理学 · 物理学 2008-11-26 Ilian T. Iliev , Garrelt Mellema , Ue-Li Pen , Hugh Merz , Paul R. Shapiro , Marcelo A. Alvarez

The upcoming SKA1-Low radio interferometer will be sensitive enough to produce tomographic imaging data of the redshifted 21-cm signal from the Epoch of Reionization. Due to the non-Gaussian distribution of the signal, a power spectrum…

宇宙学与河外天体物理 · 物理学 2017-11-10 Sambit K. Giri , Garrelt Mellema , Keri L. Dixon , Ilian T. Iliev

Using the largest cosmological reionization simulation to-date (~24 billion particles), we use the genus curve to quantify the topology of neutral hydrogen distribution on scales > 1 Mpc as it evolves during cosmological reionization. We…

天体物理学 · 物理学 2009-03-02 Khee-Gan Lee , Renyue Cen , J. Richard Gott , Hy Trac

The size distribution of ionized regions during the epoch of reionization -- a key ingredient in understanding the HI power spectrum observable by 21cm experiments -- can be modelled analytically using the excursion set formalism of random…

宇宙学与河外天体物理 · 物理学 2015-06-18 Aseem Paranjape , T. Roy Choudhury

The morphology of the total gas and the neutral hydrogen (H I) distributions during the cosmological epoch of reionization can be quantified with Minkowski Functionals (MFs) of isodensity surfaces. We compute the MFs from the output of a…

天体物理学 · 物理学 2008-11-26 Liron Gleser , Adi Nusser , Benedetta Ciardi , Vincent Desjacques

We constrain the initial stage of the reionization process around progenitors of galaxies, such as the extent of the initial HII region before its fusion with the UV background and the duration of its propagation. We use a set of…

宇宙学与河外天体物理 · 物理学 2014-09-05 Jonathan Chardin , Dominique Aubert , Pierre Ocvirk

We present general properties of ionized hydrogen (HII) bubbles and their growth based on a state-of-the-art large-scale (100 Mpc/h) cosmological radiative transfer simulation. The simulation resolves all halos with atomic cooling at the…

天体物理学 · 物理学 2009-11-13 Min-Su Shin , Hy Trac , Renyue Cen

The statistical shape analysis method developed for probing the link between physical parameters and morphologies of Galactic HII regions is applied here to a set of synthetic observations (SOs) of a numerically modelled HII region. The…

星系天体物理 · 物理学 2020-07-08 Justyn Campbell-White , Ahmad A. Ali , Dirk Froebrich , Alfred Kume

We present results from a large volume simulation of Hydrogen reionization. We combine 3d radiative transfer calculations and an N-body simulation, describing structure formation in the intergalactic medium, to detail the growth of HII…

Context. The knowledge of abundance distributions is central to understanding the formation and evolution of galaxies. Most of the relations employed for the derivation of gas abundances have so far been derived from observations of outer…

星系天体物理 · 物理学 2018-01-24 M. Rodríguez-Baras , A. I. Díaz , F. F. Rosales-Ortega , S. F. Sánchez

We describe a new methodology to analyze the reionization process in numerical simulations: the chronology and the geometry of reionization is investigated by means of merger histories of individual HII regions. From the merger tree of…

宇宙学与河外天体物理 · 物理学 2015-06-11 Jonathan Chardin , Dominique Aubert , Pierre Ocvirk

We develop an analytic approach to study inhomogeneous reionization on large scales by solving the equations of ionization balance and radiative transfer to first order in perturbations. Given the spatial distribution and spectrum of the…

天体物理学 · 物理学 2008-11-26 Jun Zhang , Lam Hui , Zoltan Haiman

We present here our shape analysis method for a sample of 76 Galactic HII regions from MAGPIS 1.4 GHz data. The main goal is to determine whether physical properties and initial conditions of massive star cluster formation is linked to the…

星系天体物理 · 物理学 2018-05-02 Justyn Campbell-White , Dirk Froebrich , Alfred Kume

Cosmic reionization progresses as HII regions form around sources of ionizing radiation. Their average size grows continuously until they percolate and complete reionization. We demonstrate how this typical growth can be calculated around…

天体物理学 · 物理学 2009-11-13 Marcelo A. Alvarez , Tom Abel

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
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