Improving mid-infrared thermal background subtraction with Principal Component Analysis

Fuente: arXiv
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Autori principali: Rousseau, Hélène, Ertel, Steve, Defrère, Denis, Faramaz, Virginie, Wagner, Kevin
Natura: Preprint
Pubblicazione: 2024
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author Rousseau, Hélène
Ertel, Steve
Defrère, Denis
Faramaz, Virginie
Wagner, Kevin
author_facet Rousseau, Hélène
Ertel, Steve
Defrère, Denis
Faramaz, Virginie
Wagner, Kevin
contents Ground-based large-aperture telescopes, interferometers, and future Extremely Large Telescopes equipped with adaptive-optics systems provide angular resolution and high-contrast performance that are superior to space-based telescopes at thermal-infrared wavelengths. Their sensitivity, however, is critically limited by the high thermal background inherent to ground-based observations in this wavelength regime. We aim to improve the subtraction quality of the thermal-infrared background from ground-based observations, using Principal Component Analysis (PCA). We use data obtained with the Nulling-Optimized Mid-Infrared Camera on the Large Binocular Telescope Interferometer as a proxy for general high-sensitivity, AO-assisted ground-based data. We apply both a classical background subtraction -- using the mean of dedicated background observations -- and a new background subtraction based on a PCA of the background observations. We compare the performances of these two methods in both high-contrast imaging and aperture photometry. Compared to the classical background subtraction approach, PCA background subtraction delivers up to two times better contrasts down to the diffraction limit of the LBT's primary aperture (i.e., 350 mas in N band), that is, in the case of high-contrast imaging. Improvement factor between two and three are obtained over the mean background retrieval within the diffraction limit in the case of aperture photometry. PCA background subtraction significantly improves the sensitivity of ground-based thermal-infrared imaging observations. When applied to LBTI's nulling interferometry data, we expect the method to improve the sensitivity by a similar factor 2-3. This study paves the way to maximising the potential of future infrared ground-based instruments and facilities, such as the future 30m-class telescopes.
format Preprint
id arxiv_https___arxiv_org_abs_2405_18043
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Improving mid-infrared thermal background subtraction with Principal Component Analysis
Rousseau, Hélène
Ertel, Steve
Defrère, Denis
Faramaz, Virginie
Wagner, Kevin
Instrumentation and Methods for Astrophysics
Ground-based large-aperture telescopes, interferometers, and future Extremely Large Telescopes equipped with adaptive-optics systems provide angular resolution and high-contrast performance that are superior to space-based telescopes at thermal-infrared wavelengths. Their sensitivity, however, is critically limited by the high thermal background inherent to ground-based observations in this wavelength regime. We aim to improve the subtraction quality of the thermal-infrared background from ground-based observations, using Principal Component Analysis (PCA). We use data obtained with the Nulling-Optimized Mid-Infrared Camera on the Large Binocular Telescope Interferometer as a proxy for general high-sensitivity, AO-assisted ground-based data. We apply both a classical background subtraction -- using the mean of dedicated background observations -- and a new background subtraction based on a PCA of the background observations. We compare the performances of these two methods in both high-contrast imaging and aperture photometry. Compared to the classical background subtraction approach, PCA background subtraction delivers up to two times better contrasts down to the diffraction limit of the LBT's primary aperture (i.e., 350 mas in N band), that is, in the case of high-contrast imaging. Improvement factor between two and three are obtained over the mean background retrieval within the diffraction limit in the case of aperture photometry. PCA background subtraction significantly improves the sensitivity of ground-based thermal-infrared imaging observations. When applied to LBTI's nulling interferometry data, we expect the method to improve the sensitivity by a similar factor 2-3. This study paves the way to maximising the potential of future infrared ground-based instruments and facilities, such as the future 30m-class telescopes.
title Improving mid-infrared thermal background subtraction with Principal Component Analysis
topic Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2405.18043