Asgard/NOTT: L-band nulling interferometry at the VLTI: I. Simulating the expected high-contrast performance

Romain Laugier*, Denis Defrère, Julien Woillez, Benjamin Courtney-Barrer, Felix A. Dannert, Alexis Matter, Colin Dandumont, Simon Gross, Olivier Absil, Azzurra Bigioli, Germain Garreau, Lucas Labadie, Jérôme Loicq, Marc-Antoine Martinod, Alexandra Mazzoli, Gert Raskin, Ahmed Sanny

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)
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Abstract

Context. NOTT (formerly Hi-5) is a new high-contrast L′ band (3.5-4.0 μm) beam combiner for the VLTI designed with an ambitious aim to be sensitive to young giant exoplanets down to 5 mas separation around nearby stars. The performance of nulling interferometers in these wavelengths is affected both by fundamental noise from the background and contributions of instrumental noise. This motivates the development of end-to-end simulations to optimize these instruments.

Aims. The aim of this study is to enable a performance evaluation of NOTT and inform the design of such instruments with current and future infrastructures in mind, taking into account the different sources of noise and their correlation.

Methods. SCIFYsim is an end-to-end simulator for single-mode-filtered beam combiners, with an emphasis on nulling interferometers. We use it to compute a covariance matrix of the errors. We then use statistical detection tests based on likelihood ratios to compute compound detection limits for the instrument.

Results. With the current assumptions as to the performance of the wavefront correction systems, the errors are dominated by correlated instrumental errors down to stars of magnitude 6-7 in the L band, beyond which thermal background from the telescopes and relay system becomes dominant.

Conclusions. SCIFYsim is suited to anticipating some of the challenges of design, tuning, operation, and signal processing for integrated-optics beam combiners. The detection limits found for this early version of NOTT simulation with the unit telescopes are compatible with detections at contrasts up to 105 in the L band at separations of 5-80 mas around bright stars.

Original languageEnglish
Article numberA110
Pages (from-to)1-14
Number of pages14
JournalAstronomy and Astrophysics
Volume671
DOIs
Publication statusPublished - 1 Mar 2023

Bibliographical note

Copyright © 2023 The Authors. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

Keywords

  • Methods: data analysis
  • Methods: statistical
  • Techniques: high angular resolution
  • Techniques: interferometric

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