The Lyman-alpha signature of the first galaxies

Understand

We present the Cosmic Lyman-$\alpha$ Transfer code (COLT), a massively parallel Monte-Carlo radiative transfer code, to simulate Lyman-$\alpha$ (Ly$\alpha$) resonant scattering through neutral hydrogen as a probe of the first galaxies.

• We explore the interaction of centrally produced Ly$\alpha$ radiation with the host galactic environment.
• Ly$\alpha$ photons emitted from the luminous starburst region escape with characteristic features in the line profile depending on the density distribution, ionization structure, and bulk velocity fields.
• For example, anisotropic ionization exhibits a tall peak close to line centre with a skewed tail that drops off gradually.