Probing Tidal Spin-Up in Aligned Spin Binary Black Holes

Binary black hole (BBH) systems are thought to form through either isolated binary evolution or dynamical interactions in dense stellar environments such as globular clusters. These distinct formation channels predict different distributions of BBH spin orientations and magnitudes. Previous studies have found more support for systems with spins aligned with the orbital angular momentum compared to those that are anti-aligned. In this work, using events from the GWTC-4.0 catalog, we investigate whether BBHs with aligned spins show evidence of tidal spin-up prior to merger. Our analysis provides tentative evidence for a subpopulation of tidally spun-up BBH systems.