5 research outputs found

    First Data Release of the Hyper Suprime-Cam Subaru Strategic Program

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    The Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) is a three-layered imaging survey aimed at addressing some of the most outstanding questions in astronomy today, including the nature of dark matter and dark energy. The survey has been awarded 300 nights of observing time at the Subaru Telescope and it started in March 2014. This paper presents the first public data release of HSC-SSP. This release includes data taken in the first 1.7 years of observations (61.5 nights) and each of the Wide, Deep, and UltraDeep layers covers about 108, 26, and 4 square degrees down to depths of i~26.4, ~26.5, and ~27.0 mag, respectively (5sigma for point sources). All the layers are observed in five broad bands (grizy), and the Deep and UltraDeep layers are observed in narrow bands as well. We achieve an impressive image quality of 0.6 arcsec in the i-band in the Wide layer. We show that we achieve 1-2 per cent PSF photometry (rms) both internally and externally (against Pan-STARRS1), and ~10 mas and 40 mas internal and external astrometric accuracy, respectively. Both the calibrated images and catalogs are made available to the community through dedicated user interfaces and database servers. In addition to the pipeline products, we also provide value-added products such as photometric redshifts and a collection of public spectroscopic redshifts. Detailed descriptions of all the data can be found online. The data release website is https://hsc-release.mtk.nao.ac.jp/.Comment: 34 pages, 20 figures, 7 tables, moderate revision, accepted for publication in PAS

    The Hyper Suprime-Cam SSP survey: Overview and survey design

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    Hyper Suprime-Cam (HSC) is a wide-field imaging camera on the prime focus of the 8.2-m Subaru telescope on the summit of Mauna Kea in Hawaii. A team of scientists from Japan, Taiwan, and Princeton University is using HSC to carry out a 300-night multi-band imaging survey of the high-latitude sky. The survey includes three layers: the Wide layer will cover 1400 deg2 in five broad bands (grizy), with a 5 σ point-source depth of r ≈ 26. The Deep layer covers a total of 26 deg2 in four fields, going roughly a magnitude fainter, while the UltraDeep layer goes almost a magnitude fainter still in two pointings of HSC (a total of 3.5 deg2). Here we describe the instrument, the science goals of the survey, and the survey strategy and data processing. This paper serves as an introduction to a special issue of the Publications of the Astronomical Society of Japan, which includes a large number of technical and scientific papers describing results from the early phases of this survey

    Daunorubicin can eliminate iPS-derived cancer stem cells via ICAD/CAD-independent DNA fragmentation

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    Aim: To identify a drug that can effectively eliminate these cancer stem cells (CSCs) and determine its mode of action.Methods: CSCs were obtained from mouse induced pluripotent stem cells (miPSCs) using cancer cell-conditioned media. Drug screening was performed on these cells or after transplantation into mice. Apoptosis was analyzed by flow cytometry and western blotting.Results: Drug screening studies showed that daunorubicin, a topoisomerase II inhibitor, is specifically cytotoxic to miPS-CSCs. Daunorubicin-induced apoptosis was found to be associated with p53 accumulation, activation of the caspase cascade, and oligonucleosomal DNA fragmentation. Treatment with the caspase inhibitor abolished daunorubicin-induced DNA fragmentation and was therefore considered to act downstream of caspase activation. This was also suppressed by treatment with a Ca2+-specific chelator, which suggested that CAD endonuclease does not contribute. Moreover, no obvious ICAD reduction/degradation was detected.Conclusion: Daunorubicin effectively eliminated CSCs, which are dependent on the p53/caspase signaling cascade. The current findings provided the basis for further studies on CSC-targeted drugs for the development of cancer treatment strategies

    Second Data Release of the Hyper Suprime-Cam Subaru Strategic Program

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    International audienceThis 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|2^2| in all five broad-band filters (⁠|grizygrizy|⁠) to the nominal survey exposure (10 min in |grgr| and 20 min in |izyizy|⁠). Partially observed areas are also included in the release; about 1100 deg|2^2| is observed in at least one filter and one exposure. The median seeing in the i-band is |0.6{0_{.}^{\prime \prime }6}|⁠, demonstrating the superb image quality of the survey. The Deep (26 deg|2^2|⁠) and UltraDeep (4 deg|2^2|⁠) data are jointly processed and the UltraDeep-COSMOS field reaches an unprecedented depth of |i28i\sim 28| at |5σ5 \, \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|2^2|⁠). All products are available at the data release site, https://hsc-release.mtk.nao.ac.jp/

    The Hyper Suprime-Cam SSP survey: Overview and survey design

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    Hyper Suprime-Cam (HSC) is a wide-field imaging camera on the prime focus of the 8.2-m Subaru telescope on the summit of Mauna Kea in Hawaii. A team of scientists from Japan, Taiwan, and Princeton University is using HSC to carry out a 300-night multi-band imaging survey of the high-latitude sky. The survey includes three layers: the Wide layer will cover 1400 deg2 in five broad bands (grizy), with a 5 σ point-source depth of r ≈ 26. The Deep layer covers a total of 26 deg2 in four fields, going roughly a magnitude fainter, while the UltraDeep layer goes almost a magnitude fainter still in two pointings of HSC (a total of 3.5 deg2). Here we describe the instrument, the science goals of the survey, and the survey strategy and data processing. This paper serves as an introduction to a special issue of the Publications of the Astronomical Society of Japan, which includes a large number of technical and scientific papers describing results from the early phases of this survey
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