Searching for Z = 6.5 Galaxies with Multislit Windows

A method for searching for emission-line objects in " windows " between atmospheric emission lines using multislits is described. A search for Ly α emitters at z = 6.5 in the 9130Å window using this technique is being carried out with the multi-object spectrograph on CFHT. This technique could be extended to similar windows at longer wavelengths , aided by the (1 + z) factor in observed equivalent widths. In the J band there are windows corresponding to Ly α at z = 7.7, 8.7 and 9.3; in the H band, there are two at z = 11.9 and 13.4. Multislit window observations in these bands coupled with photometric redshift information offer perhaps the best method of the detecting extremely high redshift galaxies.