Astronomy Colloquium

The discovery of an unusual population of galaxies with extremely strong nebular line emission has come as a panacea to several problems in galaxy evolution. These objects, classified as Halpha emitters, were first detected in the z>5 Universe in deep Spitzer imaging, where they dominate the spectroscopically confirmed star-forming galaxy population. Since then, they have been re-discovered in the local Universe in the Sloan   
Digital Sky Survey where they constitute 0.04% of the spectroscopic sample, and at intermediate redshift using Hubble/WFC3 grism surveys. Their ubiquity in the distant Universe and the unusual properties of their stellar population make them strong candidates for being progenitors of massive galaxies at z~2 and for being the primary sources responsible for reionization. I will present our work in identifying these galaxies, insights
into the mechanism for fueling star-formation in these objects and their role in reionization. The merits of using multiwavelength observations in obtaining an improved understanding of high redshift galaxy populations will in particular be highlighted.