Hi intensity mapping with the MIGHTEE Survey: first results of the Hi power spectrum

Journal article

We present the first results of the H i intensity mapping power spectrum analysis with the MeerKAT International GigaHertz Tiered Extragalactic Exploration (MIGHTEE) survey. We use data covering 4 square degrees in the COSMOS field using a frequency range of 962.5–1008.42 MHz, equivalent to H i emission in . The data consist of 15 pointings with a total of 94.2 h on-source. We verify the suitability of the MIGHTEE data for H i intensity mapping by testing for residual systematics across frequency, baselines, and pointings. We also vary the window used for H i signal measurements and find no significant improvement using stringent Fourier mode cuts. We compute the H i power spectrum at scales in autocorrelation as well as cross-correlation between observational scans using power spectrum domain averaging for pointings. We report consistent upper limits of 29.8 mK Mpc from the 2 cross-correlation measurements and 25.82 mK Mpc from autocorrelation at 2 Mpc.The low signal-to-noise ratio in this data potentially limits our ability to identify residual systematics, which will be addressed in the future by incorporating more data in the analysis.

Authors: Mazumder, A; Wolz, L; Chen, Z; Paul, S; Santos, MG

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Oxford University Press
• Journal: Monthly Notices of the Royal Astronomical Society
• Volume: 541
• Issue: 1
• Pages: 476-493
• Publication date: 2025-06-13
• Acceptance date: 2025-06-11
• DOI: 10.1093/mnras/staf975
• EISSN: 1365-2966
• ISSN: 0035-8711
• Language: English
• Keywords: techniques: interferometric; radio lines: galaxies; large-scale structure of Universe; cosmology: observations