Speaker: Laura Pentericci (Rome, visiting Cambridge)
The epoch of re-ionization is a fascinating time in the history of the
Universe and many uncertainties still plague our understanding of when
and how it occurred.

Lyman alpha emitting galaxies at high redshift offer a powerful probe to
study both reionization and the process of galaxy formation. In
particular Lyman alpha emission is an efficient tool for identifying young
galaxies and for measuring how much neutral hydrogen is present in their
environment, thus providing a reionization test that is independent of
the Gunn-Peterson trough observations in quasar spectra.

The last two years have seen a number of discoveries that offered the
first glimpse of the Universe at z =7, using both space and ground-based
telescopes.
I will review the most recent observational results on high redshift
galaxies and the current constrains that we can place on the reionization
epoch using the first statistical samples of spectroscopically confirmed
z=7 Lyman break galaxies, the evolution of the luminosity functions and
of the clustering strength
of Lyalpha emitters.