Statistical recovery of the BAO scale from multipoles of the beam-convolved 21 cm correlation function

ABSTRACT Despite being designed as an interferometer, the MeerKAT radio array (a Square Kilometre Array pathfinder) can also be used in autocorrelation (‘single-dish’) mode, where each dish scans sky independently. Operating this mode allows extremely high survey speeds to achieved, albeit at significantly lower angular resolution. We investigate recovery of baryon acoustic oscillation (BAO) scale from multipoles redshift-space correlation function measured by a low resolution 21 cm intensity mapping kind. Our approach is construct analytic model and their covariance matrix that includes foreground contamination beam effects, which we then use generate ensemble mock data vectors attempt recover BAO scale. In line with previous studies, find transverse ?? hampered strong smoothing effect instrumental increasing redshift, while radial ?? much more robust. The multipole formalism naturally incorporates information when it available however, so there no need perform radial-only analysis. particular, quadrupole preserves distinctive ‘bump’ feature even for large scales. robustness accuracy, severity removal cuts, accuracy model, finding all cases recovered accurate, unbiased manner.