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Related papers: RAY-RAMSES: a code for ray tracing on the fly in N…

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We model weak gravitational lensing of light by large-scale structure using ray tracing through N-body simulations. The method is described with particular attention paid to numerical convergence. We investigate some of the key…

Astrophysics · Physics 2008-11-26 Chris Vale , Martin White

We introduce Magrathea-Pathfinder, a relativistic ray-tracing framework that can reconstruct the past light cone of observers in cosmological simulations. The code directly computes the 3D trajectory of light rays through the null geodesic…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-24 Michel-Andrès Breton , Vincent Reverdy

Several extensions of the standard cosmological model include scalar fields as new degrees of freedom in the underlying gravitational theory. A particular class of these scalar field theories include screening mechanisms intended to hide…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-04 Claudio Llinares , David F. Mota , Hans A. Winther

We present a code allowing to evolve three-dimensional self-gravitating collisionless systems with a large number of particles N >= 10^7. FLY (Fast Level-based N-bodY code) is a fully parallel code based on a tree algorithm. It adopts…

Astrophysics · Physics 2007-05-23 U. Becciani , V. Antonuccio-Delogu , F. Buonomo , C. Gheller

A method for ray-tracing through n-body simulations has been recently proposed. It is based on a periodic universe covered by simulation boxes. Photons move along appropriate directions to avoid periodicity effects. Here, an improved…

Astrophysics · Physics 2009-11-11 L. Antón , P. Cerdá-Durán , V. Quilis , D. Sáez

FLY is a parallel treecode which makes heavy use of the one-sided communication paradigm to handle the management of the tree structure. In its public version the code implements the equations for cosmological evolution, and can be run for…

Astrophysics · Physics 2009-11-10 V. Antonuccio-Delogu , U. Becciani , D. Ferro

We propose a new ray-tracing algorithm to measure the weak lensing shear and convergence fields directly from N-body simulations. We calculate the deflection of the light rays lensed by the 3-D mass density field or gravitational potential…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Baojiu Li , Lindsay J. King , Gong-Bo Zhao , HongSheng Zhao

We describe the simulation data produced by a pilot programme to compute mock weak gravitational lensing maps for a range of currently popular cosmological models by ray tracing through high-resolution N-body simulations. The programme…

Astrophysics · Physics 2008-11-26 Martin White , Chris Vale

A new N-body and hydrodynamical code, called RAMSES, is presented. It has been designed to study structure formation in the universe with high spatial resolution. The code is based on Adaptive Mesh Refinement (AMR) technique, with a tree…

Astrophysics · Physics 2014-10-13 Romain Teyssier

We implement a model for the two-point statistics of biased tracers that combines dark matter dynamics from $N$-body simulations with an analytic Lagrangian bias expansion. Using Aemulus, a suite of $N$-body simulations built for emulation…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-23 Nickolas Kokron , Joseph DeRose , Shi-Fan Chen , Martin White , Risa H. Wechsler

Numerical methods for radiative transfer play a key role in modern-day astrophysics and cosmology, including study of the inhomogeneous reionization process. In this context, ray tracing methods are well-regarded for accuracy but notorious…

Instrumentation and Methods for Astrophysics · Physics 2025-12-16 Nathan X. Marshak , Kathlynn Simotas , Zarija Lukić , Hyunbae Park , James Ahrens , Chris R. Johnson

This is the first in a series of papers devoted to fully general-relativistic $N$-body simulations applied to late-time cosmology. The purpose of this paper is to present the combination of a numerical relativity scheme, discretization…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-29 David Daverio , Yves Dirian , Ermis Mitsou

I begin with a brief history of N-body simulation and visualization and then go on to describe various methods for creating images and animations of modern simulations in cosmology and galactic dynamics. These techniques are incorporated…

Astrophysics · Physics 2008-12-18 John Dubinski

We have developed non-sequential ray-tracing software which is aimed to be widely used, along with air- shower simulations, in the design of optical systems for cosmic-ray experiments. The code is based on the ROOT geometry library to…

Instrumentation and Methods for Astrophysics · Physics 2015-05-30 Akira Okumura , Masaaki Hayashida , Hideaki Katagiri , Takayuki Saito , Vladimir Vassiliev

The code we describe (FLY) is a newly written code (using the tree N-body method), for three-dimensional self-gravitating collisionless systems evolution. FLY is a fully parallel code based on the tree Barnes-Hut algorithm and periodical…

Astrophysics · Physics 2009-11-06 U. Becciani , V. Antonuccio-Delogu

A cosmological hydrodynamic code is described, which includes a routine to compute cosmic ray acceleration and transport in a simplified way. The routine was designed to follow explicitly diffusive acceleration at shocks, and second-order…

Astrophysics · Physics 2007-05-23 Dongsu Ryu , Francesco Miniati , Tom W. Jones , Hyesung Kang

We introduce a new particle-based hybrid code for planetary accretion. The code uses an $N$-body routine for interactions with planetary embryos while it can handle a large number of planetesimals using a super-particle approximation, in…

Earth and Planetary Astrophysics · Physics 2015-09-01 Ryuji Morishima

We present a new high-resolution N-body algorithm for cosmological simulations. The algorithm employs a traditional particle-mesh technique on a cubic grid and successive multilevel relaxations on the finer meshes, introduced recursively in…

Astrophysics · Physics 2009-10-30 Andrey V. Kravtsov , Anatoly A. Klypin , Alexei M. Khokhlov

Cosmological simulations of structures and galaxies formations have played a fundamental role in the study of the origin, formation and evolution of the Universe. These studies improved enormously with the use of supercomputers and parallel…

Astrophysics · Physics 2010-11-11 U. Becciani , V. Antonuccio , M. Comparato

We study cosmic shear statistics using the ray-tracing simulation combined with a set of large $N$-body simulations. In this contribution, we first describe our method. Then we show some selected results especially focusing on effects of…

Astrophysics · Physics 2009-10-31 Takashi Hamana , Stephane Colombi , Yannick Mellier
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