IberiCos 2025

Session

Session 9 - Observational Cosmology

16 Apr 2025, 10:15

Auditorium C.1

Conveners

Session 9 - Observational Cosmology

• Session convener: José Fonseca

46. Cosmological implications of the TDiff invariant models

Javier de Cruz Pérez (Universidad de Córdoba)

16/04/2025, 10:15

Talk

The symmetry group of general relativity is the group of diffeomorphisms (Diff), which means that the form of the physical equations remains invariant under general coordinate transformations. We discuss the cosmological implications of breaking the Diff invariance down to transverse diffeomorphisms (TDiff) invariance in the matter sector. We show that even simple cases, like a minimally...

63. JWST observations and state of cosmic anomalies

Dr Ruchika Ruchika (University of Salamanca)

16/04/2025, 10:30

Talk

Observations from the James Webb Space Telescope (JWST) have unveiled an unexpectedly high abundance of massive galaxies at early times, further challenging ΛCDM predictions. I will discuss our pioneering solutions for these tensions and their implications for the future of cosmology.

15. Illustrating the consequences of a misuse of sigma_8 in cosmology

Adrià Gómez-Valent

16/04/2025, 10:45

Talk

The parameter $\sigma_8$, which represents the root-mean-square (rms) mass fluctuations on a scale of $R_8=8h^{-1}$ Mpc (where $h$ is the reduced Hubble parameter), is commonly used to quantify the amplitude of matter fluctuations at linear cosmological scales. Derived quantities, such as $S_8=\sigma_8(\Omega_m^{0}/0.3)^{0.5}$, are also frequently employed. However, the dependence of $R_8$ on...