Widening our view of the hot Universe

Throughout the past decade, the superior capabilities of the Atacama Large Millimeter/Submillimeter Array (ALMA) have allowed astronomers to gain an unprecedented perspective on the Sunyaev-Zeldovich (SZ) effect -- a peculiar spectral signature imprinted in the ubiquitous cosmic microwave background by the warm/hot gas across the Universe. ALMA observations of the SZ effect over scales of a few arcseconds have started rivaling the more traditional X-ray measurements in terms of both resolution and sensitivity, conclusively establishing the central role of the SZ effect in the study of the thermal evolution of cosmic structures. However, the exploration of the SZ Universe with ALMA is still limited to only to a handful of pioneering studies targeting individual and/or somewhat extreme cases. In fact, the faint and diffuse nature of the SZ signal largely hampers its characterization due to major limitations inherent to radio-interferometric measurements -- namely, large-scale filtering, missing fluxes on smaller scales, and significant noise correlation in the image. Systematically extending our observational reach of the SZ effect will thus require a major advance that minimizes the impact of sparse sampling of the visibility plane while enhancing overall continuum sensitivity. In my talk, I will present detailed forecasts to discuss how the wideband sensitivity upgrade will be specifically suited for addressing such issues in the context of ALMA SZ observations.