High contrast imaging at the LBT: the LEECH exoplanet imaging survey

TL;DR

The LEECH survey at the LBT uses advanced adaptive optics and observes in the L' band to improve exoplanet detection around nearby stars, complementing other surveys and aiding JWST preparations.

Contribution

This paper presents the LEECH survey's strategy, technological advantages, and its role in exoplanet imaging at L' band, filling a niche in high-contrast imaging.

Findings

LEECH achieves competitive contrast performance.

Observations in 3-5μm aid in characterizing known exoplanets.

Survey enhances exoplanet detection around young nearby stars.

Abstract

In Spring 2013, the LEECH (LBTI Exozodi Exoplanet Common Hunt) survey began its $\sim$130-night campaign from the Large Binocular Telescope (LBT) atop Mt Graham, Arizona. This survey benefits from the many technological achievements of the LBT, including two 8.4-meter mirrors on a single fixed mount, dual adaptive secondary mirrors for high Strehl performance, and a cold beam combiner to dramatically reduce the telescope's overall background emissivity. LEECH neatly complements other high-contrast planet imaging efforts by observing stars at L' (3.8 $\mu$m), as opposed to the shorter wavelength near-infrared bands (1-2.4 $\mu$m) of other surveys. This portion of the spectrum offers deep mass sensitivity, especially around nearby adolescent ($\sim$0.1-1 Gyr) stars. LEECH's contrast is competitive with other extreme adaptive optics systems, while providing an alternative survey strategy. Additionally, LEECH is characterizing known exoplanetary systems with observations from 3-5$\mu$m in preparation for JWST.