The Atacama Cosmology Telescope (ACT) conducted an arcmin resolution survey of the southern sky at millimeter wavelengths from 2008- 2022. I present an update on the ACT search for galaxy clusters using the redshift independent Sunyaev-Zel’dovich (SZ) effect, using data from the full ACT survey, covering 15,000 square degrees. The final ACT Data Release 6 (DR6) cluster catalog is expected to contain ~ 10000 galaxy clusters with redshift and mass estimates. I describe the construction of the catalog (in particular the differences with respect to ACT DR5), products and tools associated with the data release, and discuss some science applications of the catalog.
Matt Hilton (2026) studied this question.