MIRC-X: a highly-sensitive six telescope interferometric imager at the CHARA Array

Narsireddy Anugu; Jean-Baptiste Le Bouquin; John D. Monnier; Stefan Kraus; Benjamin R. Setterholm; Aaron Labdon; Claire L Davies; Cyprien Lanthermann; Tyler Gardner; Jacob Ennis; Keith J. C. Johnson; Theo ten Brummelaar; Gail Schaefer; Judit Sturmann

arXiv · 2007.12320

MIRC-X: a highly-sensitive six telescope interferometric imager at the CHARA Array

Narsireddy Anugu·Jean-Baptiste Le Bouquin·John D. Monnier·Stefan Kraus·Benjamin R. Setterholm·Aaron Labdon·Claire L Davies·Cyprien Lanthermann·Tyler Gardner·Jacob Ennis·Keith J. C. Johnson·Theo ten Brummelaar·Gail Schaefer·Judit Sturmann

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Abstract

MIRC-X (Michigan InfraRed Combiner-eXeter) is a new highly-sensitive six-telescope interferometric imager installed at the CHARA Array that provides an angular resolution equivalent of up to a 330 m diameter baseline telescope in J and H band wavelengths ($\tfrac{\lambda}{2B}\sim0.6$ milli-arcseconds). We upgraded the original MIRC (Michigan InfraRed Combiner) instrument to improve sensitivity and wavelength coverage in two phases. First, a revolutionary sub-electron noise and fast-frame rate C-RED ONE camera based on a SAPHIRA detector was installed. Second, a new-generation beam combiner was designed and commissioned to (i) maximize sensitivity, (ii) extend the wavelength coverage to J-band, and (iii) enable polarization observations. A low-latency and fast-frame rate control software enables high-efficiency observations and fringe tracking for the forthcoming instruments at CHARA Array. Since mid-2017, MIRC-X has been offered to the community and has demonstrated best-case H-band sensitivity down to 8.2 correlated magnitude. MIRC-X uses single-mode fibers to coherently combine light of six telescopes simultaneously with an image-plane combination scheme and delivers a visibility precision better than 1%, and closure phase precision better than $1^\circ$. MIRC-X aims at (i) imaging protoplanetary disks, (ii) detecting exoplanets with precise astrometry, and (iii) imaging stellar surfaces and star-spots at an unprecedented angular resolution in the near-infrared. In this paper, we present the instrument design, installation, operation, and on-sky results, and demonstrate the imaging and astrometric capability of MIRC-X on the binary system $\iota$ Peg. The purpose of this paper is to provide a solid reference for studies based on MIRC-X data and to inspire future instruments in optical interferometry.

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Narsireddy Anugu, Jean-Baptiste Le Bouquin, John D. Monnier, Stefan Kraus, Benjamin R. Setterholm, Aaron Labdon, Claire L Davies, Cyprien Lanthermann, Tyler Gardner, Jacob Ennis, Keith J. C. Johnson, Theo ten Brummelaar, Gail Schaefer, Judit Sturmann. 2020-07-24. MIRC-X: a highly-sensitive six telescope interferometric imager at the CHARA Array. https://arxiv.org/abs/2007.12320

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