Inferring Cosmology and Astrophysics from the High-redshift 21cm Signal with SKA-Low
Anshuman Acharya, Satadru Bag, Sabrina Berger, Michele Bianco, Daniela Breitman, Lilian Crascall-Kennedy, Saswata Dasgupta, Abhirup Datta, Marian Douspis, Ivelin Georgiev, Sambit K. Giri, Adélie Gorce, Caroline Heneka, Julien Hiegel, Ian Hothi, Akanksha Kapahtia, Nicholas Kern, Yashrajsinh Mahida, Barun Maity, Suman Majumdar, Romain Mériot, Rajesh Mondal, Steven G. Murray, Leon Noble, Samit Kumar Pal, Aurel Schneider, Benoit Semelin, Abinash Kumar Shaw, Hayato Shimabukuro, Emilie Thélie, Anshuman Tripathi, Cathryn M. Trott
astro-ph.CO, astro-ph.GA
Submitted: 2026-06-26
Comments: Published in Advancing Astrophysics with the SKA II (AASKAII), 2026 (arXiv:2606.20366). Report-no:AASKAII/Acharya01
Code: https://github.com/sambit-giri/StoReS
License: http://creativecommons.org/licenses/by-nc-sa/4.0/
The gist: The Square Kilometre Array's low frequency telescope (SKA-Low) will enable inference of astrophysical and cosmological parameters from the redshifted 21 cm signal, probing the Cosmic Dawn and Epoch
Terminology
Abstract
The Square Kilometre Array's low frequency telescope (SKA-Low) will enable inference of astrophysical and cosmological parameters from the redshifted 21 cm signal, probing the Cosmic Dawn and Epoch of Reionisation. While the power spectrum is the primary target for initial detection, the inherently non-Gaussian nature of the 21 cm signal, driven by the patchy evolution of ionised regions and spin temperature fluctuations, encodes rich information accessible through higher-order statistics and morphological measurements. Extracting these constraints requires diverse inference tools, encompassing both sophisticated modelling frameworks (analytical, semi-numerical, numerical, and emulators) used to predict the 21 cm signal, and advanced inference techniques (Bayesian, simulation-based, field-level) to connect statistics to the underlying physics. This chapter reviews these tools and explores the constraining power of different statistical probes accessible with SKA-Low, including the power spectrum, statistics beyond order two, moments of the signal distribution, and morphological measures. Combining these complementary statistics is crucial for breaking parameter degeneracies and unveiling the properties of the early Universe. We specifically assess the potential of the initial SKA-Low configuration (AA*) to measure galaxy and IGM properties, demonstrating its capability for early science results. This chapter forms part of a comprehensive set detailing the Epoch of Reionisation and Cosmic Dawn science case for the SKA-Low telescope.
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