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SWIMS Subaru Telescope Observations Completed

April 26, 2023
Last updated: May 22, 2023

The near-infrared instrument SWIMS completed its observations at the Subaru Telescope on the night of December 7, 2022 (Hawaii time).

SWIMS Subaru Telescope Observations Completed Figure

Figure 1: SWIMS installed on the Cassegrain focus of the Subaru Telescope. (Credit: TAO project)

SWIMS (Simultaneous-color Wide-field Infrared Multi-object Spectrograph) has been in development since 2009 for the 6.5-m telescope at the University of Tokyo Atacama Observatory (TAO) on the summit of Cerro Chajnantor (elevation: 5,640 m) in northern Chile. Prior to departing for Chile, it conducted test observations at the Subaru Telescope since 2018 to evaluate performance, identify items for improvement, and establish operational procedures.

For two years starting from 2021, SWIMS was operated as an open-use instrument on the Subaru Telescope aiming for early scientific results, in addition to further performance verification. Many proposals were submitted targeting various objects, from stars in our galaxy to galaxies in the early Universe, reflecting researcher’s high level of interest in SWIMS.

During observations, the SWIMS team sometimes had to deal with unexpected problems. For example, when there was an electrical short between SWIMS and the telescope at an unexpected location, causing noise in the images, they had to interrupt the observation and insulate SWIMS from the telescope. In a stroke of really bad luck, the Mauna Loa volcano erupted for the first time in 38 years (Figure 2). The glow of the flowing lava lit up the night sky, and volcanic dust flew all the way up to the summit area of Maunakea, making observations difficult.

SWIMS Subaru Telescope Observations Completed Figure2

Figure 2: Flowing lava from Mauna Loa, as seen from the Subaru Telescope enclosure in November 2022. (Credit: TAO project)

Although there were some minor problems, the SWIMS team was able to complete observations without significant problems and obtained high-quality observational data for both performance verification and scientific research. Currently many researchers are actively analyzing the data and some scientific results have already been published in papers. Further results are expected in the future.

Now that it has completed observations on the Subaru Telescope, SWIMS will be transported to Japan, where modifications will be made for installation on the TAO 6.5-m telescope. Then, SWIMS will be transported to Chile and installed on the 6.5-m telescope.

SWIMS Subaru Telescope Observations Completed Figure3

Figure 3: A group photo taken after completing SWIMS’s final night on the Subaru Telescope. Observers from four locations participated, including the remote observation room at NAOJ Mitaka Campus (top left), the observation room at the Subaru Telescope (bottom right), and the homes of observers (top right and bottom left). (Credit: TAO project)

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