H i intensity mapping with MeerKAT: forecast for delay power spectrum measurement using interferometer mode

Neutral hydrogen (H i) intensity-mapping (IM) surveys are considered a promising tool for investigating the expansion history of the Universe. In this work, we explore the potential of MeerKAT H i IM observations in interferometer mode to estimate the power spectrum and constrain cosmological parameters within typical dark-energy models. We employ an approach called the 'delay spectrum', which allows us to separate the weak H i signal from foreground contamination in the frequency domain. Our findings indicate that the choice of survey fields significantly impacts the fractional errors on the power spectrum (& UDelta;P/P) within a limited observational time of 10 h. As the integration time increases from 10-10 000 h, & UDelta;P/P progressively decreases until cosmic variance begins to dominate. For a total observation time of 10 000 h, the lowest & UDelta;P/P at low k can be achieved by tracking 100 points for the MeerKAT L band (900-1200 MHz) and 10 points for the MeerKAT UHF band (580-1000 MHz). Next, we assess the performance of H i IM in constraining typical dark-energy models. We find that the MeerKAT H i IM survey in interferometer mode demonstrates limited capability in constraining the dark-energy equation of state, even when combined with Planck data. Our analysis serves as a valuable guide for future MeerKAT observations in H i IM surveys.

Automated summary

This study explores the potential of using MeerKAT H i intensity-mapping observations in interferometer mode to estimate the power spectrum and constrain cosmological parameters. The choice of survey fields has a significant impact on the fractional errors of the power spectrum within a limited observational time. Increasing the integration time gradually decreases the fractional errors until cosmic variance becomes dominant. The performance of H i intensity-mapping in constraining typical dark-energy models is found to be limited, even when combined with Planck data.