Institute for Advanced Study Astrophysics Seminar
What We Think We Know About Lyman Alpha Emitting Galaxies
The following statements are often made about high-redshift Lyman Alpha Emitting (LAE) galaxies:
1. They are young, low-dust galaxies undergoing initial bursts of star formation.
2. Due to resonant scattering, Lyman alpha photons experience much higher dust extinction than UV continuum radiation.
3. LAEs lie on the same correlation between star formation rate and stellar mass as other star-forming galaxies at the same redshift.
4. A galaxy whose observed Lyman alpha emission has rest-frame equivalent width >240 Angstroms possesses a top-heavy IMF, likely from Population III stars.
5. LAEs at z<6 are faithful tracers of the large-scale structure and can therefore be used to probe cosmology.
6. The topology of reionization can be probed via the effect of ionized bubbles on LAE clustering.
7. The high Lyman alpha escape fractions of LAEs imply sufficiently high Lyman continuum escape fractions for similar galaxies at z>7 to reionize the universe.
I will assess the validity of each of these statements, arguing that none have yet been proven and that each requires some caveats. I will then describe how we can test each (amended) statement using ongoing surveys and simulations.