Tipo de Comunicación: Oral Sesión Científica: Galaxias y

ID 38
Tipo de Comunicación: Oral
Sesión Científica: Galaxias y cosmologia
Titulo: Parameter splitting in dark energy: is dark energy the same in the background
and in the cosmic structures?
Nombre (Autor que presenta): José Luis
Apellidos (Autor que presenta): Bernal Mera
Apellidos y nombre de los autores: Bernal, José Luis; Verde, Licia; Cuesta, Antonio
With the advent of precision cosmology, the constraints on new physics beyond the
standard cosmological model are stronger than ever. However, some slight tensions
have appeared between the cosmological parameters inferred by probes of the
expansion of the Universe (mainly CMB and BAO) and the observations of the growth
of cosmic structures. Moreover, the true origin of the cosmic acceleration is still
unknown and alternative dynamical models or modifications of General Relativity have
been proposed. I present an empirical consistency test of General Relativity/dark
energy by disentangling expansion history and growth of structure constraints. In
General Relativity within minimally coupled dark energy models, the expansion history
fully determines the growth history, which is not necessarily true in modified gravity. In
the context of standard $w$CDM, I replace each late-universe parameter that
describes the behavior of dark energy with two meta-parameters: one describing
geometrical information in cosmological probes and the other controlling the growth of
structures. If the null hypothesis is fulfilled (i.e. the two meta-parameters coincide) the
underlying model is correct. If it is not, then it could be a hint of a failure in the model,
the necessity of extensions to it or systematics in the data. Thus, combining different
cosmological data sets, this consistency test also works as a probe for systematics and
inconsistencies in the data. I present a global analysis using state-of-the-art
cosmological data sets. We find that probes which depend on the growth of structures
prefer a weaker growth than that inferred by background probes. I discuss the different
possible scenarios which may lead to this result. The fact that the result is mostly
driven by a sub-set of galaxy cluster abundance data points to the need of a better
understanding of this probe before interpreting the result found as a failure of