About NINJA

NINJA (Near-Infrared and Optical Spectrograph for Joint Astronomy) is a new wide-band spectrograph being developed for the Subaru Telescope. Installed at the infrared Nasmyth focus and operated in conjunction with the Laser Tomography Adaptive Optics (LTAO) system, NINJA is designed to perform spectroscopy of near diffraction-limited images. The instrument aims to achieve high sensitivity at moderate spectral resolution (R ≈ 3000-4000).

A key feature of NINJA is its capability for simultaneous optical and near-infrared spectroscopy. By covering the optical (0.4-0.9 μm) and near-infrared (0.85-2.5 μm) wavelength ranges simultaneously, NINJA will greatly improve observing efficiency while providing broad wavelength coverage in a single observation. This capability is particularly valuable for studies of rapidly evolving and transient astrophysical phenomena.

In addition, a newly implemented beam-switching system at the infrared Nasmyth focus enables NINJA observations without instrument exchange. This allows rapid response to transient events and makes NINJA well suited for time-domain and multi-messenger astronomy.

Development Status

The ultimate goal of the NINJA project is simultaneous optical and near-infrared spectroscopy using two spectrographs covering the wavelength ranges of 0.4-2.5 μm. Development of the near-infrared spectrograph began in FY2021, with first observation planned for 2026. Development of the optical spectrograph started in FY2026, extending NINJA toward a fully integrated optical-to-near-infrared spectroscopic facility.

Collaboration

NINJA is being developed through a collaborative research program with the Advanced Technology Center (ATC) of the National Astronomical Observatory of Japan (NAOJ). Visits from students and researchers are always welcome. Please feel free to contact us if you are interested in learning more about the project.

Acknowledgments

This project is supported by the following JSPS KAKENHI grants:

• Grant-in-Aid for Scientific Research (S) “Study of r-process nucleosynthesis of gravitational wave sources by means of high sensitivity wide-band near infrared spectroscopy” (JP21H04997)
• Grant-in-Aid for Scientific Research (S) “A study of nucleosynthesis of r-process heavy elements through optical and near-infrared simultaneous spectroscopy of gravitational wave sources” (JP26K21726)

The development and laboratory testing of NINJA have been carried out as a collaborative research project with the NAOJ Advanced Technology Center, utilizing its facilities and technical resources. We also gratefully acknowledge the extensive support provided by the staff of the Subaru Telescope during the installation of NINJA and the ongoing preparation for science observations.