CONCERTO: Instrument model of Fourier transform spectroscopy, white-noise components

TL;DR

This paper presents a detailed instrument model for the CONCERTO astrophysical spectrometer, focusing on white-noise components to improve data accuracy and systematic error correction in Fourier transform spectroscopy.

Contribution

It introduces a comprehensive model of CONCERTO's white-noise components, integrating physical and simulated data to enhance observational reliability.

Findings

Characterization of photon, generation-recombination, and amplifier white-noise levels.

Model validation through comparison with on-sky observations.

Enhanced error correction capabilities for astrophysical data analysis.

Abstract

Modern astrophysics relies on intricate instrument setups to meet the demands of sensitivity, sky coverage, and multi-channel observations. An example is the CONCERTO project, employing advanced technology like kinetic inductance detectors and a Martin-Puplett interferometer. This instrument, installed at the APEX telescope atop the Chajnantor plateau, began commissioning observations in April 2021. Following a successful commissioning phase that concluded in June 2021, CONCERTO was offered to the scientific community for observations, with a final observing run in December 2022. CONCERTO boasts an 18.5 arcmin field of view and a spectral resolution down to 1.45 GHz in the 130-310 GHz electromagnetic band. We developed a comprehensive instrument model of CONCERTO inspired by Fourier transform spectrometry principles to optimize performance and address systematic errors. This model integrates instrument noises, subsystem characteristics, and celestial signals, leveraging both physical data and simulations. Our methodology involves delineating simulation components, executing on-sky simulations, and comparing results with real observations. The resulting instrument model is pivotal, enabling a precise error correction and enhancing the reliability of astrophysical insights obtained from observational data. In this work, we focus on the description of three white-noise noise components included in the instrument model that characterize the white-noise level: the photon, the generation-recombination, and the amplifier noises.