Limits on the luminosity function of Ly-alpha emitters at z = 7.7
  The Ly-alpha luminosity function (LF) of high-redshift Ly-alpha emitters
(LAEs) is one of the few observables of the re-ionization epoch accessible to
date with 8-10 m class telescopes. The evolution with redshift allows one to
constrain the evolution of LAEs and their role in re-ionizing the Universe at
the end of the Dark Ages.
  We have performed a narrow-band imaging program at 1.06 microns at the CFHT,
targeting Ly-alpha emitters at redshift z ~ 7.7 in the CFHT-LS D1 field. From
these observations we have derived a photometric sample of 7 LAE candidates at
z ~ 7.7.
  We derive luminosity functions for the full sample of seven objects and for
sub-samples of four objects. If the brightest objects in our sample are real,
we infer a luminosity function which would be difficult to reconcile with
previous work at lower redshift. More definitive conclusions will require
spectroscopic confirmation.
