Joint reconstructions of growth and expansion histories with minimal assumptions

13 Jun 2023, 15:00
20m
Conference room (2nd floor) (IBS Science and Culture Center)

Conference room (2nd floor)

IBS Science and Culture Center

Speaker

Rodrigo Calderon (Korea Astronomy and Space Science Institute (KASI))

Description

Using data from upcoming (Stage-IV) cosmological surveys, we jointly reconstruct the Universe’s growth and expansion histories using forward modeling and Gaussian Processes. Our approach only relies on a few reasonable assumptions, namely:

  • A (flat) Friedmann-Lemaître-Robertson-Walker metric,
  • An Einstein De Sitter (matter-dominated) Universe at high redshift. 


We forecast the upcoming surveys’ potential to accurately reconstruct the Dark Energy (DE) evolution and thus detect any possible deviation from a cosmological constant. We generate mock data for various alternative DE models and illustrate how our method captures the correct DE behavior in all cases — being capable of distinguishing them from $\Lambda$ at more than 95% C.L.
Finally, we extend our methodology to include possible deviations from General Relativity (GR) at low-$z$, by simultaneously reconstructing the phenomenological function $G_{\rm eff}(z)$ governing the growth of (dust-like) matter density perturbations.

Secondary category for the parallel session (optional) Cosmology

Primary author

Rodrigo Calderon (Korea Astronomy and Space Science Institute (KASI))

Co-authors

Prof. Alexei Starobinsky (L. D. Landau Institute for Theoretical Physics) Prof. Arman Shafieloo (Korea Astronomy and Space Science Institute (KASI)) Prof. Benjamin L'Huillier (Sejong University) Prof. David Polarski (Laboratoire Charles Coulomb, Montpellier Univ.)

Presentation materials