Wolfram Computation Meets Knowledge

Wolfram Summer School


Brian Kent

Summer School

Class of 2011


Brian Kent is a scientist at the National Radio Astronomy Observatory (NRAO). He earned his PhD from Cornell University. His research uses radio telescopes like the NRAO’s Very Large Array and Green Bank Telescopes to study galaxies in the nearby universe. He has studied the properties of the Virgo Cluster, mapping the gaseous content of low surface brightness galaxies. Brian also has a wide variety of technical interests, including astronomical databases, imaging techniques, and NKS simple programs. He is interested in using 2D cellular automata to examine the properties of galaxies, including their spiral structure and dynamical gas evolution. Visit his website to learn more about his astronomy and computing research.

Project: Morphology and Dynamics of Galaxies with Cellular Automata

Galaxies are among the largest observed physical systems, surpassed only by clusters, groups, and the large-scale structure of the universe. The currently accepted ∧-Cold Dark Matter model of galaxy formation gives a hierarchical formation scenario and mass distribution of dark matter halos. Once lower mass objects (~10^7 solar masses) have coalesced into larger disk galaxies but before the formation of larger Cd galaxies at the centers of virialized clusters, one theory proposes that star formation shapes and drives the morphological structure of galaxies.

An equal-area cell rotating polar grid using 2D cellular automata can be used as an effective galaxy construction and evolution tool (Gerola & Seiden, 1978, ApJ). This phenomenological model maintains spiral structure matching the morphology of spiral galaxies using input such as star formation, site size and rate, and galaxy rotation. Grids with cell numbers of order ~30,000 can be run rather rapidly, allowing for fast exploration of the parameter space. We propose to explore a number of analytical and empirical galaxy rotation curves to create a template library of cellular automata galaxies.

A quantitative measure of galaxy morphology needs to be ascertained to compare observations (perhaps at multiple wavelengths) to the CA galaxies. Polar basis functions consisting of Chebyshev rational functions TLn(r) and Fourier series (Jimenez-Teja and Benitez, 2011) can be applied to both the archival survey imaging as well as the simulations.The basis coefficients for observations and models can be used as a figure of merit or metric for comparison, matching CA template galaxies to sets of cataloged images.

Future work may include examining the entire Hubble sequence of galaxies, including dwarfs, irregulars, ellipticals, and lenticulars. The model can be modified to use multiple lists for tracking the neutral and molecular gas reservoirs. Visualizing the gas will allow a morphological comparison with high-resolution neutral hydrogen maps made with radio interferometry.

You may view the results of this project as a PDF.

Favorite Four-Color Totalistic Cellular Automaton

Rule 121393