KSZ Velocity Reconstruction with ACT and DESI-LS using a Tomographic QML Power Spectrum Estimator
The study reconstructs kinetic Sunyaev-Zel'dovich (kSZ) velocity fields using ACT DR6 and DESI-LS DR9 data. A novel quadratic maximum likelihood (QML) power spectrum estimator was developed to find the cross-power between the kSZ velocity reconstruction and galaxy density. This analysis detected a kSZ signal with an amplitude of $A=0.42 ext{ relative to a halo model prediction}$, indicating strong feedback in massive halos, and improved SNR by about 20% compared to pseudo-$C_{\ell}$ methods.