# Microphysics in computational relativistic astrophysics - 2011

Microphysics in computational relativistic astrophysics

## Other Topics Discussion 2

Friday Jun 24, 2011

## A formalism for weak solutions of GR elasticity

Friday Jun 24, 2011
Speaker(s):

I review different approaches to the kinematics and dynamics of (hyper)elasticity in GR, and describe one that is now being implemented in joint work with Ian Hawke.

Scientific Areas:

## Numrelasticity

Friday Jun 24, 2011
Speaker(s):

Nonlinear numerical relativistic elasticity may be necessary for simulations including neutron star crusts. Basic simulations of large deformations in relativistic elastic matter will be detailed, and issues necessary for more realistic simulations covered. This work is in collaboration with Carsten Gundlach.

Scientific Areas:

## Relativistic Magnetohydrodynamic Bondi--Hoyle Accretion

Friday Jun 24, 2011
Speaker(s):

I present a relativistic study of axisymmetric magnetohydrodynamic Bondi--Hoyle accretion onto a moving Kerr black hole. The equations of general relativistic magnetohydrodynamics are solved using high resolution shock capturing methods, involving the use of linearised Riemann solvers. In this study I use the ideal MHD limit, which assumes no viscosity and infinite conductivity. The fluid flow is completely specified by the adiabatic constant $Gamma$, the asymptotic speed of sound $c_s^infty$, and the plasma beta parameter $beta_P$.

Scientific Areas:

## Modeling QPOs in magnetar giant flares

Friday Jun 24, 2011
Speaker(s):

Alfven oscillations of strongly magnetized neutron stars coupled to shear modes in the solid crust could possibly explain the quasi-periodic oscillations (QPOs) observed in the giant flares of soft gamma repeaters. We present results of two-dimensional simulations of Alfven torsional oscillations in magnetars, modeled as relativistic stars with a dipolar magnetic field. We use a general relativistic magnetohydrodynamics code in the anelastic approximation, which allows for an effective suppression of fluid modes and an accurate description of the Alfven waves.

Scientific Areas:

## Combining MHD and microphysics

Friday Jun 24, 2011
Speaker(s):

I will discuss the techniques that can be used to include arbitrary equations of state in MHD simulations, particularly the ways in which one may perform conservative to primitive variable conversion numerically for such simulations.

Scientific Areas:

## Using GPUs to accelerate molecular dynamics simulations

Thursday Jun 23, 2011
Speaker(s):

GPUs can offer a less costly solution to large-scale calculations of astrophysical systems. I will outline the basics of the CUDA libraries and also compare with various metrics our in-development GPU code for molecular dynamics versus our hybrid OpenMP/MPI version.

Scientific Areas:

## Discontinuous Galerkin methods for general relativistic hydrodynamics

Thursday Jun 23, 2011

I will present the formalism needed for the application of discontinuous Galerkin methods to general relativistic hydrodynamics and the results obtained in the spherically symmetric case.

Scientific Areas:

## Choosing equations of state for neutron star inspiral

Thursday Jun 23, 2011
Speaker(s):

## Microphysics to macrophysics: Astrophysics and gravitational wave science opportunities in the advanced detector era and beyond

Thursday Jun 23, 2011

## RECENT PUBLIC LECTURE

### Emily Levesque: The Weirdest Stars in the Universe

Speaker: Emily Levesque