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相关论文: On the Proper Use of the Reduced Speed of Light Ap…

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The "Reduced Speed of Light" (RSL) approximation is commonly used to speed up radiative transfer calculations in cosmological simulations. However, it has been shown previously that the RSL approximation leads to photon non-conservation in…

宇宙学与河外天体物理 · 物理学 2025-12-03 Nickolay Y. Gnedin

The reduced speed of light approximation (RSLA) has been employed to speed up radiative transfer simulations of reionization by a factor of $\gtrsim 5-10$. However, it has been shown to cause significant errors in the HI-ionizing background…

宇宙学与河外天体物理 · 物理学 2024-12-20 Christopher Cain

The reduced speed of light approximation is used in a variety of simulations of the epoch of reionization and galaxy formation. Its popularity stems from its ability to drastically reduce the computing cost of a simulation, by allowing the…

宇宙学与河外天体物理 · 物理学 2019-06-19 P. Ocvirk , D. Aubert , J. Chardin , N. Deparis , J. Lewis

In this paper I show that simulations of reionization performed under the Cosmic Reionization On Computers (CROC) project do converge in space and mass, albeit rather slowly. A fully converged solution (for a given star formation and…

宇宙学与河外天体物理 · 物理学 2016-04-20 Nickolay Y. Gnedin

Coupled radiative-hydrodynamics simulations of the epoch of reionization aim to reproduce the propagation of ionization fronts during the transition before the overlap of HII regions. Many of these simulations use moment-based methods to…

宇宙学与河外天体物理 · 物理学 2019-02-13 Nicolas Deparis , Dominique Aubert , Pierre Ocvirk , Jonathan Chardin , Joseph Lewis

Cosmic Reionization On Computers (CROC) is a long-term program of numerical simulations of cosmic reionization. Its goal is to model fully self-consistently (albeit not necessarily from the first principles) all relevant physics, from…

宇宙学与河外天体物理 · 物理学 2015-06-19 Nickolay Y. Gnedin

We explore the connection between the stellar component of galaxies and their host halos during the epoch of reionization ($5 \leq z\leq10$) using the CROC (Cosmic Reionization on Computers) simulations. We compare simulated galaxies with…

星系天体物理 · 物理学 2021-04-20 Hanjue Zhu , Camille Avestruz , Nickolay Y. Gnedin

A reduced-speed-of-light (RSOL) approximation is a useful technique for magnetohydrodynamic (MHD)-particle-in-cell (PIC) simulations. With a RSOL, some "in-code" speed-of-light $\tilde{c}$ is set to much lower values than the true $c$,…

高能天体物理现象 · 物理学 2022-09-20 Suoqing Ji , Philip F. Hopkins

Lyman limit systems (LLSs) are dense hydrogen clouds with high enough HI column densities to absorb Lyman continuum photons emitted from distant quasars. Their high column densities imply an origin in dense environments; however, the…

星系天体物理 · 物理学 2024-03-04 Jiawen Fan , Hanjue Zhu , Camille Avestruz , Nickolay Y. Gnedin

The Varying Speed of Light (VSL) model describes how the speed of light in a vacuum changes with cosmological redshift. Despite numerous models, there is little observational evidence for this variation. While the speed of light can be…

宇宙学与河外天体物理 · 物理学 2024-09-06 Cheng-Yu Zhang , Wei Hong , Yu-Chen Wang , Tong-Jie Zhang

We present a comparison between several observational tests of the post-reionization IGM and the numerical simulations of reionization completed under the Cosmic Reionization On Computers (CROC) project. The CROC simulations match the gap…

宇宙学与河外天体物理 · 物理学 2017-05-31 Nickolay Y. Gnedin , George D. Becker , Xiaohui Fan

We compare the results from several sets of cosmological simulations of cosmic reionization, produced under Cosmic Reionization On Computers (CROC) project, with existing observational data on the high-redshift Ly-alpha forest and the…

宇宙学与河外天体物理 · 物理学 2015-06-19 Nickolay Y. Gnedin , Alexander A. Kaurov

We show that numerical simulations of reionization that resolve the Lyman Limit systems (and, thus, correctly count absorptions of ionizing photons) have converged to about 10% level for 5<z<6.2 and are in reasonable agreement (within 10%)…

天体物理学 · 物理学 2010-11-11 Nickolay Y. Gnedin , Xiaohui Fan

Low-light images captured in the real world are inevitably corrupted by sensor noise. Such noise is spatially variant and highly dependent on the underlying pixel intensity, deviating from the oversimplified assumptions in conventional…

计算机视觉与模式识别 · 计算机科学 2022-07-13 Zeyuan Chen , Yifan Jiang , Dong Liu , Zhangyang Wang

We compare the properties of stellar populations of model galaxies from the Cosmic Reionization On Computers (CROC) project with the exiting UV and IR data. Since CROC simulations do not follow cosmic dust directly, we adopt two variants of…

宇宙学与河外天体物理 · 物理学 2016-04-01 Zimu Khakhaleva-Li , Nickolay Y. Gnedin

A powerful test of fundamental physics consists on probing the variability of fundamental constants in Nature. Although they have been measured on Earth laboratories and in our Solar neighbourhood with extremely high precision, it is…

宇宙学与河外天体物理 · 物理学 2022-07-27 Gabriel Rodrigues , Carlos Bengaly

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…

Quasar absorption lines provide a unique window to the relationship between galaxies and the intergalactic medium during the Epoch of Reionization. In particular, high redshift quasars enable measurements of the neutral hydrogen content of…

宇宙学与河外天体物理 · 物理学 2025-03-17 Ella Werre , David Robinson , Camille Avestruz , Nickolay Y. Gnedin

The 21cm background from the epoch of reionization is a promising cosmological probe: line-of-sight velocity fluctuations distort redshift, so brightness fluctuations in Fourier space depend upon angle, which linear theory shows can…

宇宙学与河外天体物理 · 物理学 2013-04-17 Paul R. Shapiro , Yi Mao , Ilian T. Iliev , Garrelt Mellema , Kanan K. Datta , Kyungjin Ahn , Jun Koda

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…

天体物理学 · 物理学 2009-11-07 Aaron Sokasian , Tom Abel , Lars Hernquist , Volker Springel
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