67,252 research outputs found
Computational astrophysics
Astronomy is an area of applied physics in which unusually beautiful objects challenge the imagination to explain observed phenomena in terms of known laws of physics. It is a field that has stimulated the development of physical laws and of mathematical and computational methods. Current computational applications are discussed in terms of stellar and galactic evolution, galactic dynamics, and particle motions
Computational Relativistic Astrophysics With Adaptive Mesh Refinement: Testbeds
We have carried out numerical simulations of strongly gravitating systems
based on the Einstein equations coupled to the relativistic hydrodynamic
equations using adaptive mesh refinement (AMR) techniques. We show AMR
simulations of NS binary inspiral and coalescence carried out on a workstation
having an accuracy equivalent to that of a regular unigrid simulation,
which is, to the best of our knowledge, larger than all previous simulations of
similar NS systems on supercomputers. We believe the capability opens new
possibilities in general relativistic simulations.Comment: 7 pages, 16 figure
Numerical Relativity As A Tool For Computational Astrophysics
The astrophysics of compact objects, which requires Einstein's theory of
general relativity for understanding phenomena such as black holes and neutron
stars, is attracting increasing attention. In general relativity, gravity is
governed by an extremely complex set of coupled, nonlinear, hyperbolic-elliptic
partial differential equations. The largest parallel supercomputers are finally
approaching the speed and memory required to solve the complete set of
Einstein's equations for the first time since they were written over 80 years
ago, allowing one to attempt full 3D simulations of such exciting events as
colliding black holes and neutron stars. In this paper we review the
computational effort in this direction, and discuss a new 3D multi-purpose
parallel code called ``Cactus'' for general relativistic astrophysics.
Directions for further work are indicated where appropriate.Comment: Review for JCA
Direct N-body Simulations
Special high-accuracy direct force summation N-body algorithms and their
relevance for the simulation of the dynamical evolution of star clusters and
other gravitating N-body systems in astrophysics are presented, explained and
compared with other methods. Other methods means here approximate physical
models based on the Fokker-Planck equation as well as other, approximate
algorithms to compute the gravitational potential in N-body systems. Questions
regarding the parallel implementation of direct ``brute force'' N-body codes
are discussed. The astrophysical application of the models to the theory of
relaxing rotating and non-rotating collisional star clusters is presented,
briefly mentioning the questions of the validity of the Fokker-Planck
approximation, the existence of gravothermal oscillations and of rotation and
primordial binaries.Comment: 32 pages, 13 figures, in press in Riffert, H., Werner K. (eds),
Computational Astrophysics, The Journal of Computational and Applied
Mathematics (JCAM), Elsevier Press, Amsterdam, 199
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