Speaker
Tessa Baker
Description
Recent combinations of BAO, supernovae and CMB data prefer cosmologies with an evolving dark energy equation of state, w(z), which crosses the phantom divide (w=-1). But parameterisations of w(z) are not, in themselves, complete physical models of dark energy.
In this talk we’ll ask: what kind of underlying modified gravity or dark energy models give rise to phantom-crossing behaviour? We’ll see that crossing the phantom divide can have strong consequences for other observables, particularly for ISW-galaxy cross-correlations and voids.
I’ll present a system to triage the large gravity model space down to a set of viable, predictive theories which can be verified or falsified with Stage IV galaxy surveys.