Second data release of the Hyper Suprime-Cam Subaru Strategic Program

Abstract

This paper presents the second data release of the Hyper Suprime-Cam Subaru Strategic Program, a wide-field optical imaging survey using the 8.2 m Subaru Telescope. The release includes data from 174 nights of observation through 2018 January. The Wide layer data cover about 300 deg$^2$ in all five broad-band filters ($grizy$) to the nominal survey exposure (10 min in $gr$ and 20 min in $izy$). Partially observed areas are also included in the release; about 1100 deg$^2$ is observed in at least one filter and one exposure. The median seeing in the i-band is ${0_{.}^{\prime \prime }6}$, demonstrating the superb image quality of the survey. The Deep (26 deg$^2$) and UltraDeep (4 deg$^2$) data are jointly processed and the UltraDeep-COSMOS field reaches an unprecedented depth of $i\sim 28$ at $5 \, \sigma$ for point sources. In addition to the broad-band data, narrow-band data are also available in the Deep and UltraDeep fields. This release includes a major update to the processing pipeline, including improved sky subtraction, PSF modeling, object detection, and artifact rejection. The overall data quality has been improved, but this release is not without problems; there is a persistent deblender problem as well as new issues with masks around bright stars. The user is encouraged to review the issue list before utilizing the data for scientific explorations. All the image products as well as catalog products are available for download. The catalogs are also loaded into a database, which provides an easy interface for users to retrieve data for objects of interest. In addition to these main data products, detailed galaxy shape measurements withheld from Public Data Release 1 (PDR1) are now available to the community. The shape catalog is drawn from the S16A internal release, which has a larger area than PDR1 (160 deg$^2$). All products are available at the data release site, https://hsc-release.mtk.nao.ac.jp/.

An ALMA survey of the brightest sub-millimetre sources in the SCUBA-2–COSMOS field

“…In addition, the second data release (Aihara et al 2019) of Hyper-SuprimeCam (HSC) Subaru Strategic Program (SSP) provides , , , , and imaging (∼ 0.6 seeing) of the COSMOS field at a 3-equivalent depth of 28.1, 27.9, 27.9, 27.4, and 26.4 mag, respectively. This imaging reaches ∼ 1 mag deeper than the optical imaging used in the COSMOS2015 catalogue and we include it in our analysis.…”

The nature of CR7 revealed with MUSE: a young starburst powering extended Ly α emission at z = 6.6

“…We also use the most recent release (DR4) of ground-based NIR data in the Y , J, H and Ks bands from UltraVISTA (McCracken et al 2012) and NIR data in the YHSC band from the Hyper Suprime-Cam Subaru Strategic Program DR2 (Aihara et al 2019). Compared to earlier ground-based data on CR7, the most significant improvement is in the Ks band data, where individual components of CR7 are now detected.…”

Observational Nonstationarity of AGN Variability: The Only Way to Go Is Down!

“…The HSC survey is a wide-field optical imaging program being conducted with the 8.2 m Subaru telescope. The second public data release (made available in May 2019; Aihara et al 2019) covers around 300 deg 2 overlapping with the SDSS footprint. The HSC data in five optical bands (grizy) are sensitive down to ≈ 26th magnitude.…”