Speaker
Description
In this talk, I present a set of complementary analyses aimed at constraining late-time cosmology with DESI DR2. I first discuss a model-independent reconstruction of the expansion history, where we directly constrain the background evolution without assuming a specific dark energy parametrization, finding results consistent with the standard $w_0$--$w_a$ framework; this work also includes the development of an updated compressed CMB likelihood suitable for dark energy constraints, with ongoing extensions to neutrino mass and curvature models. I then revisit the Hubble tension from a late-time perspective, showing through a suite of toy models that modifications to the expansion history alone are insufficient, and that an evolution in Type Ia supernovae absolute magnitude is required to resolve the tension. We also present a physical modified gravity model which can achieve such a transition, albeit with some degree of tuning. Moving beyond geometric probes, I present recent progress toward DESI full-shape analyses, including constraints from DESI DR1 using folpsD, a theoretical framework for jointly modeling the power spectrum and bispectrum within an EFT-based approach. Finally, I briefly comment on ongoing contributions to modified gravity analyses within DESI, particularly in the development of pipelines for clustering and lensing observables.