Direct detection of the kinetic Sunyaev-Zel'dovich effect in galaxy clusters

Understand

We report the direct detection of the kinetic Sunyaev-Zel'dovich (kSZ) effect in galaxy clusters with a 3.5 sigma significance level.

• The measurement was performed by stacking the Planck map at 217 GHz at the positions of galaxy clusters from the Wen-Han-Liu (WHL) catalog.
• To avoid the cancelation of positive and negative kSZ signals, we used the large-scale distribution of the Sloan Digital Sky Survey (SDSS) galaxies to estimate the peculiar velocities of the galaxy clusters along the line of sight and incorporated the sign in the velocity-weighted stacking of the kSZ signals.
• Using this technique, we were able to measure the kSZ signal around galaxy clusters beyond 3R500.