Search

International audience; PFS (Prime Focus Spectrograph), a next generation facility instrument on the Subaru telescope, is now being tested on the telescope. The instrument is equipped with very wide (1.3 degrees in diameter) field of view on the Subaru's prime focus, high multiplexity by 2394 reconfigurable fibers, and wide waveband spectrograph that covers from 380nm to 1260nm simultaneously in one exposure. Currently engineering observations are ongoing with Prime Focus Instrument (PFI), Metrology Camera System (MCS), the first spectrpgraph module (SM1) with visible cameras and the first fiber cable providing optical link between PFI and SM1. Among the rest of the hardware, the second fiber cable has been already installed on the telescope and in the dome building since April 2022, and the two others were also delivered in June 2022. The integration and test of next SMs including near-infrared cameras are ongoing for timely deliveries. The progress in the software development is also worth noting. The instrument control software delivered with the subsystems is being well integrated with its system-level layer, the telescope system, observation planning software and associated databases. The data reduction pipelines are also rapidly progressing especially since sky spectra started being taken in early 2021 using Subaru Nigh Sky Spectrograph (SuNSS), and more recently using PFI during the engineering observations. In parallel to these instrumentation activities, the PFS science team in the collaboration is timely formulating a plan of large-sky survey observation to be proposed and conducted as a Subaru Strategic Program (SSP) from 2024. In this article, we report these recent progresses, ongoing developments and future perspectives of the PFS instrumentation.

PFS (Prime Focus Spectrograph), a next generation facility instrument on the Subaru telescope, is a very wide- field, massively multiplexed, and optical and near-infrared spectrograph. Exploiting the Subaru prime focus, 2394 reconfigurable fibers will be distributed in the 1.3 degree-diameter field of view. The spectrograph system has been designed with 3 arms of blue, red, and near-infrared cameras to simultaneously deliver spectra from 380nm to 1260nm in one exposure. The instrumentation has been conducted by the international collaboration managed by the project office hosted by Kavli IPMU. The team is actively integrating and testing the hardware and software of the subsystems some of which such as Metrology Camera System, the first Spectrograph Module, and the first on-telescope fiber cable have been delivered to the Subaru telescope observatory at the summit of Maunakea since 2018. The development is progressing in order to start on-sky engineering observation in 2021, and science operation in 2023. In parallel, the collaboration is trying to timely develop a plan of large-sky survey observation to be proposed and conducted in the framework of Subaru Strategic Program (SSP). This article gives an overview of the recent progress, current status and future perspectives of the instrumentation and scientific operation.

We present the launch of the Hyper Suprime-Cam Legacy Archive (HSCLA), a public archive of processed, science-ready data from Hyper Suprime-Cam (HSC). HSC is an optical wide-field imager installed at the prime focus of the Subaru Telescope and has been in operation since 2014. While ~1/3 of the total observing time of HSC has been used for the Subaru Strategic Program (SSP), the remainder of the time is used for PI programs. We have processed the data from these PI programs and make the processed, high quality data available to the community through HSCLA. The current version of HSCLA includes data taken in the first year of science operation, 2014. We provide both individual and coadd images as well as photometric catalogs. The photometric catalog from the coadd is loaded to the database, which offers a fast access to the large catalog. There are other online tools such as image browser and image cutout tool and they will be useful for science analyses. The coadd images reach 24-27th magnitudes at $5\sigma$ for point sources and cover approximately 580 square degrees in at least one filter with 150 million objects in total. We perform extensive quality assurance tests and verify the photometric and astrometric quality of the data to be good enough for most scientific explorations. However, the data are not without problems and users are referred to the list of known issues before exploiting the data for science. All the data and documentations can be found at the data release site, https://hscla.mtk.nao.ac.jp/., Comment: 12 pages, 9 figures, submitted to PASJ. Data available at https://hscla.mtk.nao.ac.jp/

PFS (Prime Focus Spectrograph), a next generation facility instrument on the 8.2-meter Subaru Telescope, is a very wide-field, massively multiplexed, optical and near-infrared spectrograph. Exploiting the Subaru prime focus, 2394 reconfigurable fibers will be distributed over the 1.3 deg field of view. The spectrograph has been designed with 3 arms of blue, red, and near-infrared cameras to simultaneously observe spectra from 380nm to 1260nm in one exposure at a resolution of ~ 1.6-2.7Å. An international collaboration is developing this instrument under the initiative of Kavli IPMU. The project recently started undertaking the commissioning process of a subsystem at the Subaru Telescope side, with the integration and test processes of the other subsystems ongoing in parallel. We are aiming to start engineering night-sky operations in 2019, and observations for scientific use in 2021. This article gives an overview of the instrument, current project status and future paths forward.

We measure cosmic weak lensing shear power spectra with the Subaru Hyper Suprime-Cam (HSC) survey first-year shear catalog covering 137deg$^2$ of the sky. Thanks to the high effective galaxy number density of $\sim$17 arcmin$^{-2}$ even after conservative cuts such as magnitude cut of $i, Comment: 43 pages, 21 figures, accepted for publication in PASJ

Hyper Suprime-Cam (HSC) is a wide-field imaging camera on the prime focus of the 8.2m Subaru telescope on the summit of Maunakea 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 deg$^2$ in five broad bands ($grizy$), with a $5\,\sigma$ point-source depth of $r \approx 26$. The Deep layer covers a total of 26~deg$^2$ 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 deg$^2$). 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., Comment: 14 pages, 7 figures, 5 tables. Corrected for a typo in the coordinates of HSC-Wide spring equatorial field in Table 5

Photometric redshifts are a key component of many science objectives in the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). In this paper, we describe and compare the codes used to compute photometric redshifts for HSC-SSP, how we calibrate them, and the typical accuracy we achieve with the HSC five-band photometry (grizy). We introduce a new point estimator based on an improved loss function and demonstrate that it works better than other commonly used estimators. We find that our photo-z's are most accurate at 0.2, Comment: 30 pages, 15 figures, 5 tables, moderate revision, accepted for publication in PASJ

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/., 34 pages, 20 figures, 7 tables, moderate revision, accepted for publication in PASJ

In this paper, we describe the optical imaging data processing pipeline developed for the Subaru Telescope's Hyper Suprime-Cam (HSC) instrument. The HSC Pipeline builds on the prototype pipeline being developed by the Large Synoptic Survey Telescope's Data Management system, adding customizations for HSC, large-scale processing capabilities, and novel algorithms that have since been reincorporated into the LSST codebase. While designed primarily to reduce HSC Subaru Strategic Program (SSP) data, it is also the recommended pipeline for reducing general-observer HSC data. The HSC pipeline includes high level processing steps that generate coadded images and science-ready catalogs as well as low-level detrending and image characterizations., Comment: 39 pages, 21 figures, 2 tables. Submitted to Publications of the Astronomical Society of Japan

Hyper Suprime-Cam (HSC) is the optical and near-infrared wide-field camera equipped on the Subaru Telescope. Its huge field of view (1.5 degree diameter) with 104 CCDs and the large mirror (8.2m) of the telescope will make us to study the Universe more efficiently. The analysis pipeline for HSC data produces processed images, and object catalogs of each CCD and stacked images. For survey in next 5 years, the number of rows in the object catalog table will reach to at least 5 x 10 9 . We show the outline of the database systems of HSC data to store those huge data.

This paper reports on the R&D status of a large-aperture Hybrid Avalanche Photo-Detector (HAPD). We have developed a 13-inch aperture HAPD and its readout system. The HAPD is a photo-detector expected to replace the photomultiplier tube (PMT) in next-generation imaging water Cherenkov detectors such as Hyper Kamiokande. We will present the recent progress made in readout system development. The readout system involves a fast sampling device. The sampling depth (number of cells) has been extended to 256 from 64 in order to measure longer waveform length. The variation in AC gain is now fixed and the input analog bandwidth improved.

We describe a weak lensing view of the downsizing of star forming galaxies based on cross correlating a weak lensing ($\kappa$) map with a predicted map constructed from a redshift survey. Moderately deep and high resolution images with Subaru/Hyper Suprime-Cam covering the 4 deg^2 DLS F2 field provide a $\kappa$ map with 1 arcmin resolution. A dense complete redshift survey of the F2 field including 12,705 galaxies with $R\leq20.6$ is the basis for construction of the predicted map. The zero-lag cross-correlation between the \kappa and predicted maps is significant at the $30\sigma$ level. The width of the cross-correlation peak is comparable with the angular scale of rich cluster at $z\sim0.3$, the median depth of the redshift survey. Slices of the predicted map in $\delta{z} = 0.05$ redshift bins enable exploration of the impact of structure as a function of redshift. The zero-lag normalised cross-correlation has significant local maxima at redshifts coinciding with known massive X-ray clusters. Even in slices where there are no known massive clusters, there is significant signal in the cross-correlation originating from lower mass groups that trace the large-scale of the universe. Spectroscopic $D_n4000$ measurements enable division of the sample into star-forming and quiescent populations. The significance of the cross-correlation with structure containing star-forming galaxies increases with redshift from $5\sigma$ at $z = 0.3$ to $7 \sigma$ at $z = 0.5$. The weak lensing results are consistent with the downsizing view of galaxy evolution established on the basis of many other independent studies., Comment: Accepted for publication in ApJ

Hyper Suprime-Cam (HSC) is an 870 Mega pixel prime focus camera for the 8.2 m Subaru telescope. The wide field corrector delivers sharp image of 0.25 arc-sec FWHM in r-band over the entire 1.5 degree (in diameter) field of view. The collimation of the camera with respect to the optical axis of the primary mirror is realized by hexapod actuators whose mechanical accuracy is few microns. As a result, we expect to have seeing limited image most of the time. Expected median seeing is 0.67 arc-sec FWHM in i-band. The sensor is a p-ch fully depleted CCD of 200 micron thickness (2048 x 4096 15 μm square pixel) and we employ 116 of them to pave the 50 cm focal plane. Minimum interval between exposures is roughly 30 seconds including reading out arrays, transferring data to the control computer and saving them to the hard drive. HSC uniquely features the combination of large primary mirror, wide field of view, sharp image and high sensitivity especially in red. This enables accurate shape measurement of faint galaxies which is critical for planned weak lensing survey to probe the nature of dark energy. The system is being assembled now and will see the first light in August 2012.

Hyper Suprime-Cam (HSC) employs 116 pieces of 2k×4k fully-depleted CCD with a total of 464 signal outputs to cover the 1.5 degrees diameter field of view. The readout electronics was designed to achieve ~5 e of the readout noise and 150000 e of the fullwell capacity with 20 seconds readout time. Although the image size exceeds 2G Bytes, the readout electronics supports the 10 seconds readout time for the entire CCDs continuously. All of the readout electronics and the CCDs have already been installed in the camera dewar. The camera has been built with equipment such as coolers and an ion pump. We report the readout performance of all channels of the electronics extracted from the recent test data.

We have developed the back-end readout electronics (BEE) for Hyper Suprime-Cam (HSC). HSC is the next generation wide-field camera to be mounted on the 8.2-meter diameter Subaru Telescope in Hawaii. It employs 116 pieces of 2k × 4k Charge Coupled Devices (CCDs) to cover a 1.5 degrees diameter field of view. The electronics system for HSC can be divided into two parts: the front-end electronics (FEE) in which analog signals from CCDs are processed and the BEE which is a digital component of the readout electronics. The BEE sends a readout clock to the CCD and FEE, receives the image data from the FEE and sends them to the data acquisition computers. The electronics are required to read the CCDs at the rate of 243k pixel/sec/CCDoutput while suppressing the readout noise smaller than about 4 electrons, so that the 2.3G byte of an image data can be read within about 10 seconds. We designed the BEE as 3U Euro-card system with seven slots (140 mm × 180 mm × 130 mm) to achieve all the requirements for HSC. The maximum readout speed was 265k pixel/sec/CCDoutput and the readout noise was smaller than 3 electrons, including the clock jitter noise of 0.1 electrons. We concluded that our back-end readout electronics have sufficient performance for HSC.

Hyper Suprime-Cam (HSC) is the next generation wide-field imager for the prime focus of Subaru Telescope, which is scheduled to receive its first light in 2011. Combined with a newly built wide-field corrector, HSC covers 1.5 degree diameter field of view with 116 fully-depleted CCDs. In this presentation, we summarize the details of the camera design: the wide-field corrector, the prime focus unit, the CCD dewar and the peripheral devices. The wide-field corrector consists of 5 lenses with lateral shift type doublet ADC element. The novel design guarantees the excellent image quality (D80

We report an analysis framework developed for the Hyper Suprime-Cam. The framework is featured by distributed parallel execution and a Python interface. With the Python interface, it collaborates with the LSST application framework. Thus we have developed a test pipeline with both the frameworks, and tested its parallelization performance.

We develop a prototype of data analysis system for the wide-field camera Hyper Suprime-Cam (HSC) at Subaru Telescope. The current prototype is optimized for data of the current Subaru prime-focus camera Suprime-Cam, which is a precursor instrument of HSC, to study the on-site data evaluation for wide-field imaging. The system conducts realtime data evaluation for every data frame obtaining statistical information including seeing, sky-background level, astrometric solution, and photometric zeropoint when available. Variations in time of the derived values are shown on a web-based status monitor. The on-demand analysis such as mosaicing analysis is performed using the data evaluation results. This system consists of analysis pipelines responsible for data processing, and the analysis organizing software for controlling analysis tasks and data flow and the database. The XML-based database maintains all the analysis results and analysis histories. Improvement of the analysis speed by parallel data processing is achieved with the aid of the organizing software. This system has started operation in general observations since March 2010, and will be extended to process the 104 CCD's of HSC. The system may be used for observing support and also possible to apply to another imaging-mode instruments in the future.

Hyper Suprime-Cam (HSC) employs 116 of 2k×4k CCDs with 464 signal outputs in total. The image size exceeds 2 GBytes, and the data can be readout every 10 seconds which results in the data rate of 210 Mbytes / sec. The data is digitized to 16-bit. The readout noise of the electronics at the readout time of 20 seconds is ~0.9 ADU, and the one with CCD is ~1.5 ADU which corresponds to ~4.5 e. The linearity error fits within ± 0.5 % up to 150,000 e. The CCD readout electronics for HSC was newly developed based on the electronics for Suprime-Cam. The frontend electronics (FEE) is placed in the vacuum dewar, and the backend electronics (BEE) is mounted on the outside of the dewar on the prime focus unit. The FEE boards were designed to minimize the outgas and to maximize the heat transfer efficiency to keep the vacuum of the dewar. The BEE boards were designed to be simple and small as long as to achieve the readout time within 10 seconds. The production of the system has been finished, and the full set of the boards are being tested with several CCDs installed in the HSC dewar. We will show the system design, performance, and the current status of the development.

The Hyper Suprime-Cam (HSC), the next generation wide-field camera proposed for the Subaru Telescope operated by the National Astronomical Observatory of Japan, employs ∼ 110 2k × 4k Charge Coupled Devices (CCDs) to cover a 1.5-degree diameter field of view. It is a requirement that the readout electronics are able to send ∼ 2 Gbytes of image data in 10 seconds while maintaining low noise. In addition, the readout system should be small and light in order to be mounted inside the camera. We have developed a prototype readout module for the Back End Electronics (BEE) of the readout system. The BEE provides a digital interface between the analog front end of the readout system and the data acquisition system (DAQ system). Two Gigabit Ethernet links are employed for data transfer between the BEE and the DAQ system. The size of our BEE module is 149 mm × 79 mm × 12 mm. We measured the data transfer rate from the readout module to the DAQ system and also estimated the noise. The data rate achieved full Gigabit Ethernet bandwidth and the noise was sufficiently low. Thus, we concluded our prototype readout module satisfied the required specification.

Hyper Suprime-Cam(HSC)isa1GigapixelCCD camerafora wide-fieldgalaxy surveyatthe Subaru8-mTelescope. It will be mounted on the prime focus of the SubaruTelescope and is scheduled to receive its first light in 2012. The primary science is to conduct a weak lensing survey over ∼ 2,000 square degrees. The HSC has a 1.5-degree-diameter fieldofview, 7timeslarger than thatofits predecessor Suprime-Cam.It consistsofalarge corrector lens systemand afocalplane equippedwith116piecesof2kx4kfully depletedCCDs. Combinedwiththesuperbimagequalityand large aperture of the Subaru telescope, the surveyusing HSC can cover a cosmological volume and reach the limiting magnitude of at least one magnitudefainter than the other surveys conducted using 4-m class telescopes. The readout electronics of the HSC consist of two parts: one is the analog front-end electronics (FEE) and the other is the digital back-end electronics (BEE). The FEE is placed in a vacuum dewar together with the CCDs, and processes the analog CCD signal into 16-bit digital data. The BEE is small and light enough to be integrated into the camera unit, and employs three linksofGigabit Ethernetto readouta 2.3-GByte singleexposure within10 secondsatfast readout operation. The readout noise from the electronics is smaller than that from CCDs.