Institut für Theoretische Physik, Phil19 (note unusal time)
TBA
Tuesday, 25 February 2025
14:15
Kosmologie und Elementarteilchenphysik
Nastassia Grimm
Model-independent tests of gravity from galaxy surveys and synergies with pulsar timing arrays
Institut für Theoretische Physik, Phil19
The vast number of modified gravity theories necessitates a systematic and comprehensive approach when analysing the data from next-generation surveys. The Weyl potential evolution, tracking the combined gravitational potential, Psi + Phi, provides a new and model-independent test of gravity. Recently, we have performed a first direct measurement of this observable from Dark Energy Survey data (C. Bonvin, I. Tutusaus & N. Grimm, Nature Commun. 15 (2024) 9295). For that, we have combined galaxy-galaxy lensing and galaxy clustering, and found a mild tension of 2.8 sigma with the Lambda CDM prediction at redshift z=0.47. Thus, more precise measurements are needed to provide conclusive results on the absence or presence of gravity modifications. In my presentation, I will discuss the state of the art, and the prospects of gaining new insights on the governing theory of gravity by measuring the Weyl potential evolution from upcoming data. In the final part of my talk, I will delve into another research field: pulsar timing arrays, and what we can learn from them in combination with cosmological large-scale structure.