The PFS (Prime Focus Spectrograph) instrumentation is nearly complete finally. The only missing hardware is the last two spectrograph modules, but the installations are ongoing well as of this abstract being written and are expected to complete very soon. On-sky engineering tests and observations have been carried out continually since September 2021 and, after the resolutions of some major issues on hardware and software, the team successfully observed many targeted stars over the entire field of view (Engineering First Light) in September 2022. The performances and operation of the instrument are being optimized e.g. in the accuracy and speed of fiber positioning process. Long integrations of relatively faint objects are being taken to validate expected increase of signal-to-noise ratio. Given the science operation will start soon after the commissioning process is complete, various procedures of proposing, planning, & executing observations, processing data & assessing their qualities, and delivering data to observers are being developed and tested. In this contribution, a top-level summary of these achievements and ongoing progresses and future perspectives will be provided.
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.
The Prime Focus
Spectrograph (PFS) survey will target the same patch of sky from several dozens
to 100 times. The problem of allocating PFS' 2394 fibers to objects over many
visits of a field is a highly non-trivial optimization problem. Our network
flow approach models the fiber allocation as a generalized network
min-cost/max-flow problem.
This methodology is inspired by SDSS, but extends this to address the
variety of requirements of the the PFS survey. Ultimately, we
solve the network flow through linear programming. This generally provides
a very good solution in reasonable amounts of time and can give a clear
quantitative measure of just “how good it is”. It allows us to define an arbitrary number of target classes with different
weights, to enforce constraints on the target distribution,
and to put caps to the number of observed objects per class.
We will present the methodology and the implementation of our approach.
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.
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