Capabilities of a fibered imager on an extremely large telescope

TL;DR

The paper presents the capabilities and recent on-sky results of the Fibered Imager foR a Single Telescope (FIRST), an ultra-high angular resolution spectro-imager that surpasses conventional adaptive optics imaging, with potential applications on larger telescopes.

Contribution

It introduces the FIRST instrument's design, recent on-sky performance, and future upgrades, highlighting its ability to achieve ultra-high angular resolution imaging beyond traditional limits.

Findings

Successful on-sky operation at Subaru Telescope with stabilized wavefront.

Ability to acquire long exposures on fainter sources.

Potential for application on larger telescopes for advanced astrophysical observations.

Abstract

FIRST, the Fibered Imager foR a Single Telescope instrument, is an ultra-high angular resolution spectro-imager, able to deliver calibrated images and measurements beyond the telescope diffraction limit, a regime that is out of reach for conventional AO imaging. FIRST achieves sensitivity and accuracy by coupling the full telescope to an array of single mode fibers. Interferometric fringes are spectrally dispersed and imaged on an EMCCD. An 18-Fiber FIRST setup is currently installed on the Subaru Coronographic Extreme Adaptive Optics instrument at Subaru telescope. It is being exploited for binary star system study. In the late 2020 it will be upgraded with delay lines and an active LiNb03 photonic beam-combining chip allowing phase modulation to nanometer accuracy at MHz. On-sky results at Subaru Telescope have demonstrated that, thanks to the ExAO system stabilizing the visible light wavefront, FIRST can acquire long exposure and operate on significantly fainter sources than previously possible. A similar approach on a larger telescope would therefore offer unique scientific opportunities for galactic (stellar physics, close companions) and extragalactic observations at ultra-high angular resolution. We also discuss potential design variations for nulling and high contrast imaging.