Hi-5 is the L'-band (3.5-4.0 μm) high-contrast imager of Asgard, an instrument suite in preparation for the visitor focus of the VLTI. The system is optimized for high-contrast and high-sensitivity imaging within the diffraction limit of a single UT/AT telescope. It is designed as a double-Bracewell nulling instrument producing spectrally-dispersed (R=20, 400, or 2000) complementary nulling outputs and simultaneous photometric outputs for self-calibration purposes. In this paper, we present an update of the project with a particular focus on the overall architecture, opto-mechanical design of the warm and cold optics, injection system, and development of the photonic beam combiner. The key science projects are to survey (i) nearby young planetary systems near the snow line, where most giant planets are expected to be formed, and (ii) nearby main sequence stars near the habitable zone where exozodiacal dust that may hinder the detection of Earth-like planets. We present an update of the expected instrumental performance based on full end-to-end simulations using the new GRAVITY+ specifications of the VLTI and the latest planet formation models.
@article{arxiv.2208.08908,
title = {L-band nulling interferometry at the VLTI with Asgard/Hi-5: status and plans},
author = {Denis Defrère and Azzurra Bigioli and Colin Dandumont and Germain Garreau and Romain Laugier and Marc-Antoine Martinod and Olivier Absil and Jean-Philippe Berger and Emilie Bouzerand and Benjamin Courtney-Barrer and Alexandre Emsenhuber and Steve Ertel and Jonathan Gagne and Adrian M. Glauser and Simon Gross and Michael J. Ireland and Harry-Dean Kenchington and Jacques Kluska and Stefan Kraus and Lucas Labadie and Viktor Laborde and Alain Leger and Jarron Leisenring and Jérôme Loicq and Guillermo Martin and Johan Morren and Alexis Matter and Alexandra Mazzoli and Kwinten Missiaen and Muhammad Salman and Marc Ollivier and Gert Raskin and Helene Rousseau and Ahmed Sanny and Simon Verlinden and Bart Vandenbussche and Julien Woillez},
journal= {arXiv preprint arXiv:2208.08908},
year = {2022}
}