Wolz, L.Murray, S. G.Blake, C.Wyithe, J. S.2026-01-022026-01-020035-8711ORCID:/0000-0001-7956-9758/work/195266028https://hdl.handle.net/1885/733802666H I intensity mapping data traces the large-scale structure matter distribution using the integrated emission of neutral hydrogen gas (H I). Cross-correlation of the intensity maps with optical galaxy surveys can mitigate foreground and systematic effects, but has been shown to significantly depend on galaxy evolution parameters of the H I and the optical sample. Previously, we have shown that the shot noise of the cross-correlation scales with the H I content of the optical samples, such that the shot noise estimation infers the average H I masses of these samples. In this paper, we present an adaptive framework for the cross-correlation of H I intensity maps with galaxy samples using our implementation of the halo model formalism which utilizes the halo occupation distribution of galaxies to predict their power spectra. We compare two H I population models, tracing the spatial halo and the galaxy distribution, respectively, and present their auto- and cross-power spectra with an associated galaxy sample. We find that the choice of the H I model and the distribution of the H I within the galaxy sample have little impact for the shape of the auto- and cross-correlations, but significantly affects the measured shot noise amplitude of the estimators, a finding we confirm with simulations. We demonstrate parameter estimation of the H I halo occupation models and advocate this framework for the interpretation of future experimental data, with the prospect of determining the H I masses of optical galaxy samples via the cross-correlation shot noise.LW is supported by an ARC Discovery Early Career Researcher Award (DE170100356). This research was conducted by the Australian Research Council Centre of Excellence for All-sky Astrophysics (CAASTRO), through project number CE110001020. This work was performed on the gSTAR national facility at Swinburne University of Technology. gSTAR is funded by Swinburne and the Australian Government’s Education Investment Fund.14enPublisher Copyright: © 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.Cosmology: large-scale structure of UniverseCosmology: theoryRadio lines: galaxies2018-11-2210.1093/mnras/sty314285065151298