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Abstract:

Fiber Multi Object Spectrograph “FMOS” on Subaru Telescope is capable of configuring 400 fibers on the 30- arcmin diameter field of view at the prime focus for near-infrared (0.9–1.8 μm) spectroscopy, and this instrument has been open as a common-use instrument since May 2010. In this article, an overview of the instrument is given first, and then the typical operational sequence in science observation and a few notable features of the instrument are explained. In (see manuscript) 5, the instrument performance in terms of fiber positioning, auto guiding, and sensitivity to emission lines are highlighted. Recently (since March 2012) a Subaru Strategic Program (SSP) has started with FMOS to conduct a wide-field galaxy survey for a cosmological experiment. Upgrading fiber configuration by using a “metrology camera” has also been under discussion, which will enable to measure the positions of the 400 fibers quickly and shorten the fiber configuration time significantly. We will also report the status of these recent activities.

Abstract:

The Visible Integral-field Replicable Unit Spectrograph (VIRUS) consists of a baseline build of 150 identical spectrographs (arrayed as 75 units, each with a pair of spectrographs) fed by 33,600 fibers, each 1.5 arcsec diameter, deployed over the 22 arcminute field of the upgraded 10 m Hobby-Eberly Telescope (HET). The goal is to deploy 82 units. VIRUS has a fixed bandpass of 350-550 nm and resolving power R~700. VIRUS is the first example of industrial-scale replication applied to optical astronomy and is capable of spectral surveys of large areas of sky. This approach, in which a relatively simple, inexpensive, unit spectrograph is copied in large numbers, offers significant savings of engineering effort, cost, and schedule when compared to traditional instruments. The main motivator for VIRUS is to map the evolution of dark energy for the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) using 0.8M Lyman-α emitting galaxies as tracers. The full VIRUS array is due to be deployed by early 2014 and will provide a powerful new facility instrument for the HET, well suited to the survey niche of the telescope. VIRUS and HET will open up wide-field surveys of the emission-line universe for the first time. We present the production design and current status of VIRUS.