Testing our Models for the Stuff Between Galaxies

Advisors: Phoebe Upton Sanderbeck and Professor Matt McQuinn

Description: Most of the matter in the Universe lies between galaxies in the intergalactic medium. The gas there is so diffuse that the it emits very little radiation. The primary way to detect it is to look at very bright supermassive black holes (quasars) and look for the absorption of intervening intergalactic gas in their spectrum. This project is to investigate the properties of intergalactic gas when the Universe was two billion years old and whether it agrees with our best models. Our best models start with a quite-educated guess for the conditions of the post-Big Bang Universe and evolve them forward in a simulation under the equations of gravity and hydrodynamics. We will be looking at a diagnostic of intergalactic gas that has not been carefully compared against cosmological simulations, namely the number of regions that have density ten times or so the cosmic mean density, to test our models for the intergalactic medium.

Project Skills: python (numpy and matplotlib libraries); elementary probability theory (Poissonian statistics and chi^2 statistic—both are much simpler than they sound and no previous knowledge of them is necessary).