paper

Exploring HI Galaxy Redshift Survey Strategies for the FAST Core Array Interferometry

arXiv:2508.16234 · doi:10.1088/1674-4527/adce90

Abstract

We explore the feasibility of HI galaxy redshift surveys with the Five-hundred-meter Aperture Spherical Telescope (FAST) and its proposed Core Array interferometry. Using semi-analytical simulations, we compare the performance of the FAST single-dish and Core Array modes in drift scan (DS) and on-the-fly (OTF) observations across different redshifts. Our results show that the FAST single-dish mode enables significant HI detections at low redshifts () but is limited at higher redshifts due to shot noise. The Core Array interferometry, with higher sensitivity and angular resolution, provides robust HI galaxy detections up to , maintaining a sufficient number density for power spectrum measurements and BAO constraints. At low redshifts ( -- ), both configurations perform well, though cosmic variance dominates uncertainties. At higher redshifts (), the Core Array outperforms the single-dish mode, while increasing the survey area has little impact on single-dish observations due to shot noise limitations. The DS mode efficiently covers large sky areas but is constrained by Earth's rotation, whereas the OTF mode allows more flexible deep-field surveys at the cost of operational overhead. Our findings highlight the importance of optimizing survey strategies to maximize FAST's potential for HI cosmology. The Core Array is particularly well-suited for high-redshift HI galaxy surveys, enabling precise constraints on large-scale structure and dark energy.

19 pages, 8 figures

References in corpus (72)