Academia Sinica Logo

Abstract:

Recent $2-4\sigma$ deviations from the Cosmological Constant $\Lambda$ suggest that dark energy may be dynamical, based on baryon acoustic oscillations and full-shape galaxy clustering analyses. This calls for even tighter dark energy constraints to narrow down its true nature. In this talk, I will show that the full-shape power spectrum of the intrinsic shape alignments of galaxies can tighten dark energy constraints obtained from the full-shape galaxy clustering. We perform Fisher forecasts on various extensions of dynamical dark energy models, including scenarios with curvature, massive neutrinos, and modified gravity. Our results show that the full-shape intrinsic alignment information improves the dark energy Figure-of-Merit by $42-57\%$, promoting the intrinsic alignment of galaxy shapes as a valuable cosmological probe complementary to galaxy clustering.