The cross-power spectrum between 21 cm emission and galaxies in hierarchical galaxy formation models

Park, J.; Kim, H.-S.; Wyithe, J.S.B.; Lacey, Cedric G.

Abstract

The correlation between 21 cm fluctuations and galaxies is sensitive to the astrophysical properties of the galaxies that drove reionization. Thus, detailed measurements of the cross-power spectrum and its evolution could provide a powerful measurement of both the properties of early galaxies and the process of reionization. In this paper, we study the evolution of the cross-power spectrum between 21 cm emission and galaxies using a model which combines the hierarchical galaxy formation model GALFORM implemented within the Millennium-II dark matter simulation, with a semi-numerical scheme to describe the resulting ionization structure. We find that inclusion of different feedback processes changes the cross-power spectrum shape and amplitude. In particular, the feature in the cross-power spectrum corresponding to the size of ionized regions is significantly affected by supernovae feedback. We calculate predicted observational uncertainties of the cross-correlation coefficient based on specifications of the Murchison Widefield Array (MWA) combined with galaxy surveys of varying area and depth. We find that the cross-power spectrum could be detected over several square degrees of galaxy survey with galaxy redshift errors σz ≲ 0.1.

Citation

Park, J., Kim, H., Wyithe, J., & Lacey, C. G. (2014). The cross-power spectrum between 21 cm emission and galaxies in hierarchical galaxy formation models. Monthly Notices of the Royal Astronomical Society, 438(3), 2474-2482. https://doi.org/10.1093/mnras/stt2366

• Journal Article Type: Article
• Publication Date: Mar 1, 2014
• Deposit Date: Jun 27, 2014
• Publicly Available Date: Jul 3, 2014
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 438
• Issue: 3
• Pages: 2474-2482
• DOI: https://doi.org/10.1093/mnras/stt2366
• Keywords: Galaxies: high-redshift, Cosmology: Theory, Dark ages, Reionization, First stars, Diffuse, Radiation.
• Public URL: https://durham-repository.worktribe.com/output/1449145
• Publisher URL: http:/dx.doi.org/10.1093/mnras/stt2366