Pushing Back Studies of Galaxies Toward the Dark Ages: High-Redshift   Lyman alpha Emission-Line Galaxies in the Field
  Lyman alpha emission presents a means of identifying very high redshift galaxies, provided such objects can be reliably distinguished from foreground emission-line galaxies. Here we report on a program of imaging and spectroscopic studies being conducted with the Keck telescope, in concert with additional efforts from the ground and with HST, to study such high-redshift objects over the range from z=3 to 7. The first deep narrow-band imaging studies with Keck are used to show that strong Lyman alpha emitters, such as have been seen in high-redshift quasar fields at z>4.5, can be found in the field populations. Based on studies of the HDF and the Hawaii Survey Fields these are significant contributors to the star formation rates at these epochs. 
Esther M. Hu (Univ. of Hawaii, Institute for Astronomy)