Oral Presentation

From Hyper Suprime-Cam to Prime Focus Spectrograph

Author(s): Masayuki Tanaka (NAOJ)

Presenter: Masayuki Tanaka (NAOJ)

The Japanese community is transitioning from imaging observations with Hyper Suprime-Cam (HSC) to spectroscopic follow-up observations with Prime Focus Spectrograph (PFS). We present our recent work in the context of this transition. First, we briefly review the HSC Subaru Strategic Program and its collaborating surveys, and introduce our on-going efforts to identify z>~2 clusters with abundant population of quiescent galaxies. We then turn our attention to PFS and introduce the instrument, science operations, and initial results. PFS started its science operations in March 2025, and thanks to its high multiplexity over a wide area, we have collected spectra of more than 100,000 objects in the first few observing runs. The observatory has prepared/accepted filler programs to use spare fibers to improve the overall observing efficiency. One such filler programs is the observatory filler, which is a public program with no proprietary period. We present our first results based on the observatory filler data to showcase the power of PFS.