We present a comparison between the published optical, IR and CO
spectroscopic redshifts of 15 (sub-)mm galaxies and their photometric redshifts
as derived from long-wavelength (radio-mm-FIR) photometric data. The redshift
accuracy measured for 12 sub-mm galaxies with at least one robustly-determined
colour in the radio-mm-FIR regime is dz=0.30 (r.m.s.). Despite the wide range
of spectral energy distributions in the local galaxies that are used in an
un-biased manner as templates, this analysis demonstrates that photometric
redshifts can be efficiently derived for sub-mm galaxies with a precision of dz
< 0.5 using only the rest-frame FIR to radio wavelength data.Comment: submitted to MNRAS (1 object removed from analysis, shortening of
paper
