The Subaru Deep Field: The Optical Imaging Data

The Subaru Deep Field (SDF) project is a program of Subaru Observatory to carry out a deep galaxy survey over a blank field as large as $34' \times 27'$ . The program consists of very deep multi-band optical imaging, near-infrared imaging for smaller portions of the field, and follow-up optical spectroscopy. The major scientific goals of the project are to construct large samples of Lyman-break galaxies at $z \simeq 4 \hbox{--} 5$ and Lyman alpha emitters at $z \simeq 5.7$ and 6.6, and to make detailed studies of these very high-redshift galaxy populations. In this paper, we describe the optical imaging observations and data reduction, presenting mosaicked images and object catalogs in seven bandpasses. The optical imaging was made through five broad-band filters, $B$ , $V$ , $R$ , $i'$ , $z'$ , and two narrow-band filters, NB816 ( $\lambda_{\mathrm{c}} = 8150 \,{Å}$ ) and NB921 ( $\lambda_{\mathrm{c}}=9196 \,{Å}$ ) with almost 10 hour integrations for each band. The limiting magnitudes measured at $3 \,\sigma$ on a $2^{\prime\prime}$ aperture are $B=28.45$ , $V=27.74$ , $R=27.80$ , $i'=27.43$ , $z'=26.62$ , $\mathrm{NB816} = 26.63$ , and $\mathrm{NB921}=26.54$ in the AB system. The object catalog constructed for each of the seven bands contains more than $10^5$ objects. The galaxy number counts corrected for detection incompleteness and star-count contributions are found to be consistent with previous results in the literature. Mosaicked images and catalogs of all the bands have been made open to the public on 2004 October 1 on the SDF project website. 1