Speaker
Description
We present a rigorous extension of the multi-tracer power spectrum
formalism to a three-tracer framework, systematically deriving the covariance and Fisher information matrices for three distinct biased tracers. Applied to a joint analysis of the DESI Bright Galaxy Survey, the HI Galaxy
Survey, and SKA1-Band2 intensity mapping, the formalism incorporates
redshift-space distortions and expands the covariance structure from a
3 × 3 to a 6 × 6 matrix, capturing all auto- and cross-power spectra. Our
signal-to-noise ratio analysis over 0.1 ≤ z ≤ 0.5 confirms that the full
three-tracer data vector consistently outperforms auto-correlations alone
at all redshifts, with cross-correlations proving particularly valuable in
noise-limited regimes near z ∼ 0.45. These results demonstrate the sta-
tistical potential of the three-tracer approach and lay the groundwork for
forthcoming parameter estimation with next-generation surveys such as
DESI, Euclid, and SKAO.