The Evolution of the Galaxy Stellar Mass Function in Sunyaev-Zeldovich Selected Galaxy Clusters from ACT DR5

An important observable of galaxy populations is their stellar mass function (SMF), which describes the number density of galaxies as a function of stellar mass. In the context of galaxy clusters, which are massive gravitationally-bound systems, the SMF becomes particularly important as it provides crucial information about the distribution of stellar masses within clusters and the mechanisms that lead to this observed distribution. Thus, accurate measurements of the cluster SMF can help us understand the impact of the cluster environment on galaxy formation and evolution. In this poster/presentation, I will discuss the role of the galaxy SMF in galaxy clusters and present our current work on this topic. In this work, we will be studying the galaxy population of a large sample of Sunyaev-Zel’dovich (SZ) selected galaxy clusters, drawn from the fifth data release of the Atacama Cosmology Telescope (ACT DR5), by measuring their composite cluster SMFs using optical data from the Dark Energy Camera Legacy Survey (DECaLS). Taking advantage of accurate photometry from DECaLS, photometric redshifts will be used to construct redshift-binned and cluster mass-binned composite SMFs. This type of SMF study has never been performed on this specific cluster sample. Implementing these methods on the ACT DR6 cluster sample (yet to be released) using deep photometry from the Vera C. Rubin Observatory is a logical way forward for this research.