Constraints on Dynamical Dark Energy from Multiple Probes in the Dark Energy Survey

We present constraints on the $w_0w_a$ parametrization of the equation of state of dark energy obtained from the combination of multiple Dark Energy Survey (DES) datasets: type Ia supernovae (SN), baryon acoustic oscillations (BAO) and, for the first time, weak gravitational lensing and galaxy clustering (3$\times$2pt) measurements from the full six years of survey (DES Y6). The combination yields the tightest constraints on $w_0w_a$ ever obtained from a single survey, and is consistent with a cosmological constant at $2.2\sigma$ statistical significance. Adding BAO measurements from the Dark Energy Spectroscopic Instrument (DESI) improves the figure of merit by more than a factor of two, enabling low-redshift constraints that are independent of the cosmic microwave background (CMB). That combination yields results that are similarly consistent with the cosmological constant hypothesis at the $2.3\sigma$ level. Finally, when combined with primordial CMB information, the constraints further improve by another factor of two, hinting at dynamical dark energy at $3.1\sigma$ significance --- a result that is mainly driven by the SN, BAO and CMB datasets. We also show that the level of consistency between CMB and 3$\times$2pt measurements of the $S_8$ parameter is unchanged in $w_0w_a$ when analyzed in combination with BAO and SN data.