Line-Intensity Mapping

TL;DR

Line-Intensity Mapping (LIM) is a promising technique for three-dimensional mapping of the high-redshift universe, offering insights into cosmic evolution, galaxy formation, and fundamental cosmology, with ongoing developments in modeling, experiments, and data analysis.

Contribution

This review summarizes the LIM framework, its scientific goals, experimental challenges, and future prospects, highlighting recent results and potential for groundbreaking discoveries.

Findings

First detections of LIM signals have been achieved.

LIM can probe the Epoch of Reionization and Cosmic Dawn.

Cross-correlation with other surveys enhances scientific insights.

Abstract

Line-Intensity Mapping (LIM) has emerged as a powerful technique for studying large-scale structure and the high-redshift universe, enabling three-dimensional maps of line emission across vast cosmological volumes. In this review, we summarize the LIM framework, its key scientific goals, and its future prospects. We describe the landscape of emission line tracers, theoretical modeling approaches, anticipated signals, and data-analysis methodologies. We also discuss experimental challenges, particularly those posed by astrophysical foregrounds, and review possible mitigation strategies. Further, we highlight a range of cross-correlation science cases, linking LIM with other cosmological surveys. Finally, we summarize current and upcoming experiments and early results, including recent first detections, while outlining the outlook for future discoveries. Specifically, LIM may offer new insights into galaxy formation and evolution and cosmology, while revealing the Epoch of Reionization, Cosmic Dawn, and possibly the Cosmic Dark Ages. LIM enables cosmological measurements that complement other probes and provide unique access to the high-redshift universe, potentially shedding light on dark matter, dark energy, and cosmic inflation.