Abstract

Contributed Talk - Splinter LIM

Friday, 11 September 2026, 17:15   (MW-2050)

Line intensity mapping with the ALMA interferometer

Christos Karoumpis
Univeristy of Bonn

In preparation for the CCAT/FYST EoR-Spectrometer Deep Spectroscopic Survey (EoR-Spec DSS), we reanalyze archival Atacama Large Millimeter/submillimeter Array (ALMA) observations to place new constraints on CO($J_{ m up}=3$–6) line emission from galaxies at redshifts $z=1$–5. Using a line intensity mapping (LIM) approach, which measures the cumulative emission from unresolved galaxy populations, we focus on the COSMOS field to probe the small-scale, shot-noise-dominated regime of CO emission. By applying LIM analysis techniques to archival interferometric data cubes, we derive new constraints on the CO luminosity function over a broad range of cosmic time. These measurements improve our understanding of the molecular gas content of galaxies at intermediate redshifts while refining predictions for CO foreground contamination in the EoR-Spec DSS, which aims to detect high-redshift ($zsim3$–8) [CII] line-intensity fluctuations. We describe our analysis methodology, discuss the challenges of recovering LIM signals from interferometric datasets, and demonstrate how archival ALMA observations can serve as valuable pathfinders for future CCAT/FYST surveys.