Intensity mapping cross-correlations II: HI halo models including shot noise
Abstract
H 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.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- March 2019
- DOI:
- 10.1093/mnras/sty3142
- arXiv:
- arXiv:1803.02477
- Bibcode:
- 2019MNRAS.484.1007W
- Keywords:
-
- cosmology: theory;
- cosmology: large-scale structure of Universe;
- radio lines: galaxies;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 15 pages, 8 figures, 3 tables. Comments welcome