The First-Light Instrument Suite at TMT: capabilities and status update

Abstract

The Thirty Meter Telescope (TMT) will host three science instruments at first light: IRIS (InfraRed Imaging Spectrograph), WFOS (Wide Field Optical Spectrograph), and MODHIS (Multi-Objective Diffraction-limited High-resolution Infrared Spectrograph). IRIS is a workhorse imager and spectrograph coupled to the Narrow-Field InfraRed Adaptive Optics System (NFIRAOS) to exploit the gains possible when working at the diffraction limit on an extremely large telescope. It has an imager field of view of 34 by 34 square arcseconds, and the integral field spectrograph supports a variety of spaxel scales and fields of view at resolutions between 4000 and 10,000. MODHIS, also working behind NFIRAOS, will focus on exoplanet science and will deliver precision radial velocity measurements at a spectral resolution of 100,000 for a single object. WFOS is the workhorse optical multi-object imaging spectrograph. It has an 8.3 by 3 square arcminute field of view and is capable of targeting 96 objects at once with resolutions between 1500 and 5000. In this paper, we present overviews of the technical capabilities of each of these instruments and show how those capabilities translate into meeting key TMT science requirements. We also provide updates on the design progress of these three instruments, each of which passed a major design review in 2025: IRIS completed the first of two system-level Final Design Reviews, WFOS held its first Preliminary Design Review, and MODHIS completed its final Conceptual Design Review.