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 ′ × 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. Major scientific goals of the project are to construct large samples of Lyman-break galaxies at z ≃ 4 − 5 and Lyman alpha emitters at z ≃ 5 . 7 and 6 . 6, and to make detailed studies 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 ( λ c = 8150˚A) and NB921 ( λ c = 9196˚A) with almost 10 hours long integrations for each band. The limiting magnitudes measured at 3 σ on a 2 ′′ aperture are B = 28 . 45, V = 27 . 74, R = 27 . 80, i ′ = 27 . 43, z ′ = 26 . 62, NB816 = 26 . 63, and 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 contribution are found to be consistent with previous results in the literature. The mosaicked images and catalogs of all the bands have been made open to the public on Oct. 1, 2004 on the SDF project website at http://soaps.naoj.org/sdf/.