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Related papers: Modeling the Lyman-$\alpha$ forest with Eulerian a…

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It has been realised only recently that TeV emission from blazars can significantly heat the intergalactic medium (IGM) by pair-producing high-energy electrons and positrons, which in turn excite vigorous plasma instabilities, leading to a…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Ewald Puchwein , Christoph Pfrommer , Volker Springel , Avery E. Broderick , Philip Chang

We describe a new CSPH-TVD method for numerical integration of hydrodynamical equations. The method is based on combined Lagrange-Euler approaches, and it has been devoted to simulations of hydrodynamical flows in various astrophysical…

Computational Physics · Physics 2020-01-08 Sergey Khrapov , Alexander Khoperskov , Sergey Khoperskov

The fluctuating Gunn-Peterson approximation (FGPA) is a commonly-used method to generate mock Lyman-$\alpha$ (Ly$\alpha$) forest absorption skewers at Cosmic Noon ($z\gtrsim 2$) from the matter-density field of $N$-body simulations without…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-26 Robin Kooistra , Khee-Gan Lee , Benjamin Horowitz

We compare two techniques for following the cooling of gas and its condensation into galaxies within high resolution simulations of cosmologically representative regions. Both techniques treat the dark matter using N-body methods. One…

Astrophysics · Physics 2009-09-25 Naoki Yoshida , Felix Stoehr , Volker Springel , Simon D. M. White

We present a new approach to simulating mixtures of gas and dust in smoothed particle hydrodynamics (SPH). We show how the two-fluid equations can be rewritten to describe a single-fluid 'mixture' moving with the barycentric velocity, with…

Instrumentation and Methods for Astrophysics · Physics 2015-05-06 Daniel J. Price , Guillaume Laibe

We have developed a one-dimensional code to solve ultra-relativistic hydrodynamic problems, using the Glimm method for an accurate treatment of shocks and contact discontinuities. The implementation of the Glimm method is based on an exact…

Astrophysics · Physics 2009-10-28 L. Wen , A. Panaitescu , P. Laguna

In fluid dynamical simulations in astrophysics, large deformations are common and surface tracking is sometimes necessary. Smoothed Particle Hydrodynamics (SPH) method has been used in many of such simulations. Recently, however, it has…

Instrumentation and Methods for Astrophysics · Physics 2017-03-29 Satoko Yamamoto , Junichiro Makino

In this era of precision cosmology, a detailed physical understanding on the evolution of cosmic baryons is required. Cosmic magnetic fields, though still poorly understood, may represent an important component in the global cosmic energy…

Astrophysics · Physics 2015-06-24 Shengtai Li , Hui Li , Renyue Cen

We describe a new implementation of the one-fluid method in the SPH code Phantom to simulate the dynamics of dust grains in gas protoplanetary discs. We revise and extend previously developed algorithms by computing the evolution of a new…

Earth and Planetary Astrophysics · Physics 2018-03-28 Giulia Ballabio , Giovanni Dipierro , Benedetta Veronesi , Giuseppe Lodato , Mark Hutchison , Guillaume Laibe , Daniel J. Price

We study the evolution with redshift of the number density of Ly$\alpha$ clouds in a CDM model using numerical simulations including photo-ionization and cooling of the baryonic component. The photo-ionizing flux is consistently taken as…

Astrophysics · Physics 2019-08-17 Jan P. Mücket , Patrick Petitjean , Ronald E. Kates , Rüdiger Riediger

We analyse the performance of twelve different implementations of Smoothed Particle Hydrodynamics (SPH) using seven tests designed to isolate key hydrodynamic elements of cosmological simulations which are known to cause the SPH algorithm…

Astrophysics · Physics 2009-10-30 R. J. Thacker , E. R. Tittley , F. R. Pearce , H. M. P. Couchman , P. A. Thomas

We present a method for integrating the cosmological hydrodynamical equations including a collisionless dark matter component. For modelling the baryonic matter component, we use the Piecewise Parabolic Method (PPM) which is a high-accuracy…

Astrophysics · Physics 2007-05-23 A. Sornborger , B. Fryxell , K. Olson , P. MacNeice

We discuss the ability of the smoothed particle hydrodynamics (SPH) method combined with a grid-based solver for the Poisson equation to model mass accretion onto protostars in gravitationally unstable protostellar discs. We scrutinize…

Earth and Planetary Astrophysics · Physics 2018-09-06 Olga P. Stoyanovskaya , Nikolay V. Snytnikov , Valeriy N. Snytnikov

Our work is motivated by the analysis of ash plume dynamics, arising in the study of volcanic eruptions. Such phenomena are characterized by large Reynolds number (exceeding $10^7$) and a large number of polydispersed particles~[1]. Thus,…

We study and compare fitting methods for the Lyman-$\alpha$ (Ly$\alpha$) forest 3D correlation function. We use the nested sampler PolyChord and the community code picca to perform a Bayesian analysis which we compare with previous…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-29 Andrei Cuceu , Andreu Font-Ribera , Benjamin Joachimi

We present a new fourth-order, finite-volume hydrodynamics code named Apsara. The code employs a high-order, finite-volume method for mapped coordinates with extensions for nonlinear hyperbolic conservation laws. Apsara can handle arbitrary…

Computational Physics · Physics 2017-01-20 Annop Wongwathanarat , Hannes Grimm-Strele , Ewald Müller

Modeling and direct numerical simulation of particle-laden flows have a tremendous variety of applications in science and engineering across a vast spectrum of scales from pollution dispersion in the atmosphere, to fluidization in the…

We present predictions for the one-point probability distribution and cumulants of the transmitted QSO flux in the high redshift Lyman-$\alpha$ Forest. We make use of the correlation between the Lyman-$\alpha$ optical depth and the…

Astrophysics · Physics 2009-10-31 Enrique Gaztanaga , Rupert A. C. Croft

Although the Smoothed Particle Hydrodynamics (SPH) method has been demonstrated as a promising numerical solver for multiphase flow problems due to its Lagrangian nature, its application to complex channel flow may encounter additional…

Fluid Dynamics · Physics 2025-06-18 Zi-Yang Zhan , Zhen Chen

A highly favoured mechanism of planetesimal formation is collisional growth. Single dust grains, which follow gas flows in the protoplanetary disc, hit each other, stick due to van der Waals forces and form fluffy aggregates up to…

Earth and Planetary Astrophysics · Physics 2015-05-14 Ralf J. Geretshauser , Roland Speith , Carsten Güttler , Maya Krause , Jürgen Blum