Deep Optical Imaging of the COSMOS Field with Hyper Suprime-Cam Using Data from the Subaru Strategic Program and the University of Hawaii

Masayuki Tanaka, Guenther Hasinger, John D. Silverman, Steven Bickerton, Hisanori Furusawa, Yuichi Harikane, Esther Hu, Hiroyuki Ikeda, Yanxia Li, Henry J. McCracken, Paul A. Price, Michael A. Strauss, Michitaro Koike, Yutaka Komiyama, Sogo Mineo, Satoshi Miyazaki, Atsushi J. Nishizawa, Tadafumi Takata, Yousuke Utsumi, Yoshihiko Yamada, Naoki Yasuda

Published 2017-06-02Version 1

We present the deepest optical images of the COSMOS field based on a joint dataset taken with Hyper Suprime-Cam (HSC) by the HSC Subaru Strategic Program (SSP) team and the University of Hawaii (UH). The COSMOS field is one of the key extragalactic fields with a wealth of deep, multi-wavelength data. However, the current optical data are not sufficiently deep to match with, e.g., the UltraVista data in the near-infrared. The SSP team and UH have joined forces to produce very deep optical images of the COSMOS field by combining data from both teams. The coadd images reach depths of g=27.8, r=27.7, i=27.6, z=26.8, and y=26.2 mag at 5 sigma for point sources based on flux uncertainties quoted by the pipeline and they cover essentially the entire COSMOS 2 square degree field. The seeing is between 0.6 and 0.9 arcsec on the coadds. We perform several quality checks and confirm that the data are of science quality; ~2% photometry and 30 mas astrometry. This accuracy is identical to the Public Data Release 1 from HSC-SSP. We make the joint dataset including fully calibrated catalogs of detected objects available to the community at https://hsc-release.mtk.nao.ac.jp/.