L'-band AGPM vector vortex coronagraph's first light on LBTI/LMIRCam

TL;DR

This paper reports the first on-sky use of the L'-band AGPM vortex coronagraph on LBTI/LMIRCam, demonstrating improved sensitivity and resolution for exoplanet imaging, including clear detection of known planets around HR 8799.

Contribution

First demonstration of the L'-band AGPM vortex coronagraph on LBTI/LMIRCam, showing enhanced imaging capabilities at very small inner working angles.

Findings

Clear detection of four known planets around HR 8799

Unprecedented sensitivity limits at 0.09 arcseconds

Demonstrated potential for exoplanet imaging surveys

Abstract

We present the first observations obtained with the L'-band AGPM vortex coronagraph recently installed on LBTI/LMIRCam. The AGPM (Annular Groove Phase Mask) is a vector vortex coronagraph made from diamond subwavelength gratings. It is designed to improve the sensitivity and dynamic range of high-resolution imaging at very small inner working angles, down to 0.09 arcseconds in the case of LBTI/LMIRCam in the L' band. During the first hours on sky, we observed the young A5V star HR\,8799 with the goal to demonstrate the AGPM performance and assess its relevance for the ongoing LBTI planet survey (LEECH). Preliminary analyses of the data reveal the four known planets clearly at high SNR and provide unprecedented sensitivity limits in the inner planetary system (down to the diffraction limit of 0.09 arcseconds).