# Astro-Sonification

## Contents

## Intro

written by Jason Sadural (jsadural@ccrma.stanford.edu) comments and suggestions always welcomed

Our purpose is to explore the realm of computational physics and physical tendancies through acoustical perception. In our inate desire to explore who we are and where we come from, physicists have explored the cosmos as far as light and the age of the universe will allow for answers. From data gathered at the furthest spectrum of the universe such as the Cosmic Microwave Background to relatively closer phenomena, a standard model is devised in order for us to understand what we observe and why. Through observational Astro-physics, data from telescopes and satalites are systematically collected to confirm and converge to coefficients in our physical models as well as tendancies certian systems. Computational Astrophysicists then recreate and simulate these systems in order to test the stability and consistency of these models. Within this process, we attempt to create meaningfull sonification techniques of these simulations in 3-dimensional spatialized sound in order to better understand the physical tendancies not easily seen with current Visualization techniques.

## Computational Astrophysics

### What is Computational Astrophysics?

Computational astrophysics is the simulation of astrophysical phenomena on a computer by numerical integration of the relevant governing equations. Such simulations produce detailed solutions to highly complex problems in stellar evolution, galactic dynamics, numerical cosmology, and many other fields.

### Which simulations?

The simulation data we are going to use is from Laboratory for Laboratory for Computational Astrophysics at UCSD directed by Michael Norman. The first goal is to develop sonification techniques through data mapping of simulation experiments done by his graduate student Dave Collins (http://lca2.ucsd.edu/~dcollins/Research/). Later we hope to be able to adapt this technique to all other simulations.

Links to simulations we hope to Sonify:

- http://lca2.ucsd.edu/~dcollins/MagDensityJPGs.tar (Dave Collins current data)
- http://cosmos.ucsd.edu/~mnorman/movies/siggraph01-amr.mpeg (Mike Norman's Simulation)
- http://cosmos.ucsd.edu/~mnorman/movies/normanDFest864.mpeg (Mike Norman's Simulation)

Software currently used to create simulation data:

- ZEUS-2D: A one- or two-dimensional explicit Eulerian grid code for astrophysical radiation magnetohydrodynamics.

- ZEUS-3D: A one-, two- or three-dimensional explicit Eulerian grid code for astrophysical magnetohydrodynamics.

- ZEUS-MP: A parallel, three-dimensional explicit Eulerian grid code for astrophysical magnetohydrodynamics.

- TITAN: A one-dimensional implicit adaptive mesh code for radiation hydrodynamics.

- [KRONOS]: A three-dimensional grid-based hydrodynamics cosmology code combining the piecewise parabolic method (PPM) with the particle-mesh (PM) algorithm for collisionless particles.

- Enzo: an adaptive mesh refinement (AMR), grid-based hybrid code (hydro + N-Body) which is designed to do simulations of cosmological structure formation.

- [MGMPI]: A parallel, multigrid linear system solver for second order PDEs.

- 4D2: An interactive tool for visualizing and animating 3D data (array, particle) on Silicon Graphics workstations.

- [LCA Vision]: The portable rewrite of 4D2 including support for adaptive mesh refinement data.

Another notable project that has many simulations we hope to sonify is the Athena Project. This project has many notable simulations that are fundamental to understanding physics in our universe.

## Computer Music

### Sonificatiion Technique

The software we will be using for sonification playback is Pure Data created by Miller Puckette currently Associate Director of the Center for Research in Computing and the Arts (CRCA). PD will be the interface that we will use to reparameterize the simulation data into various sonic and spatialization tools.

### Data Transposition

Dave Collins will write C-code to a 3-dimensional array data set.

We will use d