2006ApJS..162...20B

We compute accurate redshift distributions to I_AB=24 and R_AB=24.5 using photometric redshifts estimated from six-band UBVRIZ photometry in the Canada-France Deep Fields Photometric Redshift Survey (CFDF-PRS). Our photometric redshift algorithm is calibrated using hundreds of CFRS spectroscopic redshifts in the same fields. The dispersion in redshift is σ/(1+z)≲0.04 to the CFRS depth of I_AB=22.5, rising to σ/(1+z)≲0.06 at our nominal magnitude and redshift limits of I_AB=24 and z≤1.3, respectively. We describe a new method to compute N(z) that incorporates the full redshift likelihood functions in a Bayesian iterative analysis, and we demonstrate in extensive Monte Carlo simulations that it is superior to distributions calculated using simple maximum likelihood redshifts. The field-to-field differences in the redshift distributions, while not unexpected theoretically, are substantial even on 30' scales. We provide I_ABand R_AB redshift distributions, median redshifts, and parameterized fits of our results in various magnitude ranges, accounting for both random and systematic errors in the analysis.