Instrument simulator and data reduction pipeline for the ilocater spectrograph

Abstract

iLocater is a near-infrared (NIR) radial velocity (RV) spectrograph that is being developed for the Large Binocular Telescope in Arizona. Unlike seeing-limited designs, iLocater uses adaptive optics to inject starlight directly into a single-mode fiber. This feature offers high spectral resolution while simultaneously maintaining a compact optical design. Although this approach shows promise to generate extremely precise RV measurements, it differs from conventional Doppler spectrographs, and therefore carries additional risk. To aid with the design of the instrument, we have developed a comprehensive simulator and data reduction pipeline. In this paper, we describe the simulation code and quantify its performance in the context of understanding terms in a RV error budget. We find that the program has an intrinsic precision of σ<5 cm s−1, thereby justifying its use in a number of instrument trade studies. The code is written in MATLAB and available for download on GitHub.