A new measurement of the bulk flow of X-ray luminous clusters of galaxies

Understand

We present new measurements of the large-scale bulk flows of galaxy clusters based on 5-year WMAP data and a significantly expanded X-ray cluster catalogue.

• Our method probes the flow via measurements of the kinematic Sunyaev-Zeldovich (SZ) effect produced by the hot gas in moving clusters.
• It computes the dipole in the cosmic microwave background (CMB) data at cluster pixels, which preserves the SZ component while integrating down other contributions.
• Our improved catalog of over 1,000 clusters enables us to further investigate possible systematic effects and, thanks to a higher median cluster redshift, allows us to measure the bulk flow to larger scales.