Unveiling the Cosmos: Subaru Telescope’s Groundbreaking Tool for Understanding Universe’s Origins and Evolution

The Subaru Telescope, situated on Maunakea, has announced the incorporation of a new capability–a
remarkable compound eye that enables the telescope to concurrently observe approximately 2,400 celestial entities.

This groundbreaking tool, the Prime Focus Spectrograph, can capture cosmic rainbows (spectra), facilitating an in-depth examination of the universe.

It consists of around 2,400 prisms dispersed across the vast field of view provided at the Subaru Telescope’s primary focus, enabling simultaneous spectroscopic observations of thousands of celestial bodies.

This unparalleled capacity will assist researchers in accurately comprehending the formation and evolution of galaxies and the cosmos, establishing the Prime Focus Spectrograph as one of the flagship instruments of the Subaru Telescope 2.0 era.

The Subaru Telescope’s exceptionally broad field of view, roughly 1.3 degrees in diameter at the prime focus, combined with its world-renowned large light-collecting capability, allows the spectrograph to position 2,400 fibers to gather light from celestial objects and simultaneously obtain spectra across the entire visible spectrum and part of the near-infrared region.

Similar to the compound eyes of insects, each facet (fiber) concentrates in a distinct direction to cover a broad area while perceiving the hues of light from that direction. This ambitious instrument will significantly boost the Subaru Telescope’s spectroscopic observation efficiency.

Following nearly 15 years of work supported by industrial partners worldwide, the development of the Prime Focus Spectrograph has been spearheaded by an international consortium of over 20 research institutions from Japan, the U.S., France, Brazil, Taiwan, Germany, and China, inclusive of scientists, engineers, and technicians based in Hawaiʻi.

Notably, the University of Tokyo Kavli Institute for the Physics and Mathematics of the Universe has taken the lead in proposing and developing the instrument, as well as planning wide-sky survey observations aimed at testing various theoretical frameworks regarding the formation of the cosmos.

The Subaru Telescope at the National Astronomical Observatory of Japan has also played a key role, participating in the instrument’s development and overseeing project coordination while managing the acceptance and operation of the device. Numerous PFS components and modules manufactured and assembled in diverse countries were converged on Maunakea and integrated into the Subaru Telescope.

Since 2021, the international team has carried out engineering tests and observations with the Subaru Telescope and will commence scientific operations shortly.

“Throughout the production, assembly, and testing phases, I have been tirelessly working to unite individuals and teams scattered across different institutions. It is profoundly gratifying to witness it all coming together as a cohesive instrument system,” stated Naoyuki Tamura, professor and project manager of Prime Focus Spectrograph at Subaru Telescope. “However, this is merely a stepping stone towards our ultimate objectives, such as maintaining operations long-term, generating groundbreaking scientific results, and fully sharing thrilling updates from Maunakea with the local community.”

The revelations that will be uncovered with this state-of-the-art instrument are a source of pride for all the people of Hawai’i; to participate in the heart of such a significant international collaboration and human endeavor,” he emphasized.

The PFS team anticipates conducting a large-sky survey program over the coming five years,
utilizing a total of 360 nights of telescope time. This survey will capture spectra from millions of remote galaxies, as well as hundreds of thousands of stars within the Milky Way and our nearby Andromeda Galaxy.