Year: 2026
Type: preprint
Abstract: Line intensity mapping (LIM) has emerged as a powerful tool for surveying the large-scale structure of the Universe across cosmic time by measuring spatial fluctuations in the cumulative emission of spectral lines from unresolved sources or the intergalactic medium. Besides the most abundant 21-cm hyperfine line of neutral hydrogen, there are bright far-infrared fine-structure lines like [CII] 158 $μ$m, [OIII] 88 $μ$m, [NII] 122/205 $μ$m, and [OI] 63 $μ$m, as well as mid-/high-$J$ CO rotational transitions, hydrogen Ly$α$ and H$α$ as potential LIM probes. A key opportunity lies in combining and cross-correlating 21-cm intensity maps from SKAO with other line intensity maps, targeted by a range of ongoing and forthcoming LIM experiments that probe overlapping cosmic volumes. Cross-correlation between 21-cm maps and other line tracers mitigates uncorrelated systematics and enhances sensitivity to the underlying matter distribution, while multi-line analyses help disentangle cosmological and astrophysical parameters. Beyond cross-power spectra, higher-order and morphological statistics -- such as cross-bispectra, marked correlations, and morphological measures -- capture non-Gaussian features and the environmental dependence of structure formation. This chapter explores the synergies that can be achieved by combining SKAO observations with other line-intensity mapping experiments, demonstrating how such joint analyses can unlock new insights into galaxy evolution and cosmology.
Source: arXiv (Cornell University)
Authors: Sarkar, Debanjan, Majumdar, Suman, Murmu, Chandra Shekhar, Noble, Leon, Dosibhatla, Manas Mohit, Pandya, Vishrut, Bernal, José Luis, Mahida, Yashrajsinh, Kamran, Mohd, Heneka, Caroline S., Tripathi, Anshuman, Pal, Samit Kumar, De Lucia, Gabriella, Fontanot, Fabio, Viel, Matteo, Spinelli, Marta, Kothari, Parth, Libanore, Sarah, Shaw, Abinash Kumar, Sahlen, Martin, Fonseca, José, Datta, Abhirup, Sakr, Ziad, Hu, Wenkai
Institutions: Trottier Space Institute at McGill, McGill University, Indian Institute of Technology Indore, The Open University, Instituto de Física de Cantabria, Trieste Astronomical Observatory, Heidelberg University, Scuola Internazionale Superiore di Studi Avanzati, Lagrange Laboratory, Observatoire de la Côte d’Azur, University of the Western Cape, Ben-Gurion University of the Negev, Uppsala University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, Department of Science and Technology, Ministry of Science and Technology, India, Volkswagen Foundation, Abdus Salam International Centre for Theoretical Physics, Bundesministerium für Bildung und Forschung, Ministry of Education, India, Scheme for Promotion of Academic and Research Collaboration, Natural Sciences and Engineering Research Council of Canada, Science and Engineering Research Board, Fonds de recherche du Québec – Nature et technologies, Agencia Estatal de Investigación
OpenAlex ID: W7166700352