Abstract

Optical interferometry enables observations on spatial scales as small as a few milliarcseconds, allowing for unique science such as directly observing the inner few astronomical units around nearby pre-main sequence stars and imaging stellar disks. It is not without its limitations however, one of which is the limiting magnitude an interferometer and its beam combiner (science instrument) can reach. The Magdalena Ridge Observatory Interferometer (MROI) is a next generation array designed to address this shortcoming and perform observations on targets five to seven magnitudes fainter than is currently possible at other arrays. In line with this goal the array’s initial science beam combiner, FOURIER , is strictly optimised for sensitivity leading to a novel design.

In this talk I will outline the main science requirements and discuss how the design of FOURIER contributes to meeting these requirements. I will also present the first laboratory characterisation of the instrument including validation of the PSF profile, demonstration of high contrast fringes, and the spectral resolution of the instrument. I will conclude by discussing the path to deployment of FOURIER at the MROI ahead of the first science observations at the array.