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Full-Text Articles in Astrophysics and Astronomy
Finite Difference Schemes For Second Order Systems Describing Black Holes, Mohammad Motamed, Maria Babiuc-Hamilton, B. Szilágyi, H-O. Kreiss, J. Winicour
Finite Difference Schemes For Second Order Systems Describing Black Holes, Mohammad Motamed, Maria Babiuc-Hamilton, B. Szilágyi, H-O. Kreiss, J. Winicour
Maria Babiuc-Hamilton
In the harmonic description of general relativity, the principal part of Einstein’s equations reduces to 10 curved space wave equations for the components of the space-time metric. We present theorems regarding the stability of several evolution-boundary algorithms for such equations when treated in second order differential form. The theorems apply to a model black hole space-time consisting of a spacelike inner boundary excising the singularity, a timelike outer boundary and a horizon in between. These algorithms are implemented as stable, convergent numerical codes and their performance is compared in a 2-dimensional excision problem.
Dark Matter As An Integral Part Of An Alternative Gravity Model, Hontas Farmer
Dark Matter As An Integral Part Of An Alternative Gravity Model, Hontas Farmer
Hontas F Farmer
The purpose of this paper is to reconcile observations of dark matter effects on the galactic and cosmological scales with the null results of astroparticle physics observations such as CDMS and ANTARES. This paper will also provide a candidate unified and simpler mathematical formulation for the Lambda CDM model. Unification is achieved by a combination of the f(R) approach, with the standard LCDM approach and inflationary models. It is postulated that dark matter-energy fields depend on the Ricci curvature R. Standard methods of classical and quantum field theory on curved space time are applied. When this model is treated as …