The new Near-Infrared Adaptive-Optics assisted high-resolution NIRPS spectrograph on the ESO 3.6m

The Near-InfraRed Planet Searcher (NIRPS) is a new ultra-stable near-infrared spectrograph installed on ESO 3.6-m Telescope in La Silla, Chile. Aiming to achieve a precision of 1 m/s, NIRPS is operating together with HARPS. NIRPS has been designed to explore the exciting prospects offered by the M dwarfs, focusing on three main science cases: 1) High-precision RV survey of M dwarf aiming at detecting Earth-like planets in the habitable zone; 2) Mass (and density) measurements of planetary candidates orbiting M dwarfs from transit surveys, and 3) Atmospheric characterization of exoplanets via transmission spectroscopy. To achieve its science goals, NIRPS is operating in the Y-, J- and H-bands with continuous coverage from 0.97 to 1.8 μm. It will ensure high radial velocity precision and high spectral fidelity corresponding to 1 m/s in less than 30 min for an M3 star with H = 8.4. NIRPS is part of a new generation of adaptive optics (AO) fiber-fed spectrographs. NIRPS uses a 0.4-arcsecond multi-mode fiber, half that required for a seeing-limited instrument, allowing a spectrograph design that is half as big as that of HARPS, while meeting the requirements for high throughput and high spectral resolution. A 0.9-arcsecond fiber is used for fainter targets and degraded seeing conditions. The entire optical design is oriented to maximize high spectral resolution, long-term spectral stability and overall throughput. The instrument covers the 0.97 to 1.81 μm domain on 69 spectral
 orders with a spectral resolution of 80,000 recorded on a Hawaii 4RG 4096 × 4096 infrared detector. In return for the manpower effort and financial contributions of the consortium to design, build, maintain and operate NIRPS for five years, ESO will grant the consortium a period of Guaranteed Time Observation (GTO) corresponding to 40% of the 3.6-m Telescope time, leaving ample time for community-driven science topics. Its first light was performed in May 2022. We present here the performance of the spectrograph and first tests on sky.