Structure Formation in the Early Universe

Here at the IfA, Dr. Avery Meiksin along with post doc Eric Tittley and graduate student Simon Reynolds are exploring structure formation from galaxies to large scales in the early universe (100 > z > 1.5) using numerical simulations, with emphasis on the baryonic matter.

Goals

Why?

Structure Formation is Important

The physics of structure formation is complicated

Structure Formation is Complicated

Observing high-redshift structure

QSO absorption spectra allow us to measure the state of the intervening (mostly) ionised gas.

Lya spectra cartoon Lya spectra

Scattering of CMB photons by free electrons permits measurement of the optical depth of the ionised gas.

CMB scattering

Mapping of the redshifted 21 cm line of HI reveals the structure of reionisation.

CMB scattering

Work at University of Edinburgh's Institute for Astronomy

At the IfA, we have developed a unique code with which to study the epoch of reionsation. We have written a radiative transer (RT) code that determines not only the correct ionisation fractions, but also the temperatures.

Coupling the radiative transfer code to a particle-mesh (PM) code allows us to model reionisation in the early universe.

PMRT result

Movies

Movies of an ionisation front passing through a 25 h-1 Mpc (comoving) volume from z=8 to 3.

A Quasar in the centre of a 35 h-1 Mpc comoving volume. Gridding by undergraduate student Calum Brown.


Unless explicitly stated otherwise, all material is copyright Eric Tittley