We present our deep Y -band imaging data of a two square degree field within the F22 region of the VIMOS VLT Deep Survey .
The observations were conducted using the WIRCam instrument mounted at the Canada–France–Hawaii Telescope ( CFHT ) .
The total on-sky time was 9 hours , distributed uniformly over 18 tiles .
The scientific goals of the project are to select faint quasar candidates at redshift z > 2.2 , and constrain the photometric redshifts for quasars and galaxies .
In this paper , we present the observation and the image reduction , as well as the photometric redshifts that we derived by combining our Y -band data with the CFHTLenS u ^ { * } g ^ { \prime } r ^ { \prime } i ^ { \prime } z ^ { \prime } optical data and UKIDSS DXS JHK near-infrared data .
With J -band image as reference total \sim 80,000 galaxies are detected in the final mosaic down to Y -band 5 \sigma point source limiting depth of 22.86 mag .
Compared with the \sim 3500 spectroscopic redshifts , our photometric redshifts for galaxies with z < 1.5 and i ^ { \prime } \lesssim 24.0 mag have a small systematic offset of | \Delta { z } | \lesssim 0.2 , 1 \sigma scatter 0.03 < \sigma _ { \Delta z } < 0.06 , and less than 4.0 % of catastrophic failures .
We also compare to the CFHTLenS photometric redshifts , and find that ours are more reliable at z \gtrsim 0.6 because of the inclusion of the near-infrared bands .
In particular , including the Y -band data can improve the accuracy at z \sim 1.0 - 2.0 because the location of the 4000Å-break is better constrained .
The Y -band images , the multi-band photometry catalog and the photometric redshifts are released at \url http : //astro.pku.edu.cn/astro/data/DYI.html .