IRMS is a near-diffraction-limited multislit near-infrared spectrometer and imager. It will operate behind NFIRAOS, over the 0.8 - 2.5 um wavelength range. Closely modeled after the Keck instrument MOSFIRE, IRMS will employ a cryogenic slit assembly with 46 individually-configurable slits. The slits can be positioned within a 2 arcmin field. The detector scale is 60 mas/pixel and the spectral resolution is about R = 5000 for a 160 mas slit width (lower with wider slits). The imager covers a 2.27 arcmin diameter FOV with 60 mas sampling. IRMS will be an early-light instrument on the TMT.

IRMS Specification

Wavelength Coverage 0.8 - 2.5 μm
Observing Modes Imaging and Multi-slit Spectroscopy
Spectral Resolution R=5000
Spacial Scales 0.06″
Field Size 2.1′ × 2.1′
Image Quality NFIRAOS Wide-Field Mode (Φ120″)
Filters z, J, H, K
Detector 2048 × 2048 H2RG and ASIC; 18 μm pixels
Multiplex Cryogenic Configurable Slit Unit
Minimum Slit Width: 0.16″
Up to 46 Slits