The Large Fiber Array Spectroscopic Telescope

Chad Bender
University of Arizona
Steward Observatory
Wednesday, May 8, 2024
3:45 pm
ISEB 1200

Abstract: The Large Fiber Array Spectroscopic Telescope (LFAST) is currently being designed and prototyped at the University of Arizona. The LFAST project's primary objective is to provide large and scalable collecting area, equivalent to or greater than other Extremely Large Telescopes (ELTs) at a dramatically reduced cost per square-meter of aperture. LFAST will be well suited to science cases that require large aperture and high-spectral-resolution on demand. This includes characterizing the atmospheric chemistry of transiting exoplanets, including searching for bio-signatures in Earth-like planets with the goal of assessing habitability, as well as science cases at greater distances such as followup of transients discovered by Rubin including supernovae, neutron star and black-hole mergers, and gamma ray bursts, . The scalable nature of LFAST means that collecting area much larger than the existing ELTs could be constructed and deployed at observatories distributed longitudinally around the globe, increasing the collecting area while reducing the observability window that limits single-dish facilities making time critical observations.

LFAST is an array telescope, and will combine the light from hundreds or thousands of individual “unit telescopes” into a single spectrometer. Each unit consists of a prime focus telescope with a 0.76-m diameter spherical primary mirror and a refractive prime focus corrector, feeding a fused silica fiber. Twenty units will be mounted on a common alt-az mount, providing 9 m^2 of collecting area, equivalent to a traditional 3.5m telescope. An full array of 132 such systems will provide area of 1200 m^2, slightly larger than the E-ELT. I will describe how LFAST tackles various exoplanet science cases, the current status of our first 20-unit prototype, and our plans for future development of the spectrometer instrumentation.

Paul Robertson