CONCERTO at APEX: Installation and first phase of on-sky commissioning

TL;DR

CONCERTO is a large-field spectro-imager installed on the APEX telescope, designed to study cosmic reionisation, galaxy clusters, and molecular gas through advanced KID technology, with initial commissioning results presented.

Contribution

This paper details the design, installation, and initial on-sky commissioning of CONCERTO, a novel large-field spectro-imager for the APEX telescope.

Findings

Successful installation and commissioning of CONCERTO at APEX.

First on-sky tests demonstrate instrument functionality.

Initial scientific capabilities confirmed for key astrophysical programs.

Abstract

CONCERTO (CarbON CII line in post-rEionisation and ReionisaTiOn) is a large field-of-view (FoV) spectro-imager that has been installed on the Cassegrain Cabin of Atacama Pathfinder EXperiment (APEX) telescope in April 2021. CONCERTO hosts 2 focal planes and a total number of 4000 Kinetic Inductance Detectors (KID), with an instantaneous FoV of 18.6 arcminutes in the range of 130-310 GHz. The spectral resolution can be easily tuned down to 1 GHz depending on the scientific target. The scientific program of CONCERTO has many objectives, with two main programs focused on mapping the fluctuations of the [CII] line intensity in the reionisation and post-reionisation epoch (4.5<z<8.5), and on studying galaxy clusters via the thermal and kinetic Sunyaev-Zel'dovich (SZ) effect. CONCERTO will also measure the dust and molecular gas contents of local and intermediate-redshift galaxies, it will study the Galactic star-forming clouds and finally it will observe the CO intensity fluctuations arising from 0.3<z<2 galaxies. The design of the instrument, installation at APEX and current status of the commissioning phase and science verification will be presented. Also we describe the deployment and first on-sky tests performed between April and June 2021.