Lyman-alpha emission: from local starbursts to cosmological populations

by Mr Matthew Hayes (Stockholm Observatory)

Friday 25 May 2007, 10:15 → 11:15 Europe/Stockholm

FA31

The Hydrogen Lyman-alpha (Lya) emission line is currently the most powerful observational tracer through which to probe the galaxy population at high redshift (z). The feature is frequently so bright that the very highest redshifts can be probed with relatively modest time investment on modern large diameter reflectors. Tests for high-z clustering parameters, cosmic star-formation history, and the final stages of re-ionisation are all, in principle, within a few nights observation. However, Lya is a resonant line and given the high abundance of neutral hydrogen in galaxies (and the intergalactic medium at very high z), its line formation is subject to a complex radiative transport. Due to the high competition in the cosmological community, many interpretations drawn from high-z datasets do not include considerations for Lya astrophysics. I will review some Lya theoretical studies and previous space-based low-z observations, and present the latest results of our HST imaging survey of local starbursts. I will (hopefully) discuss the implicatiosn of these results for the cosmological community.