Observational constraints on cosmological future singularities

Jose Beltrán Jiménez (1, 2) , Ruth Lazkoz (3) , Diego Sáez-Gómez (4) , Vincenzo Salzano (5)

1 CPT - Centre de Physique Théorique - UMR 7332
2 CPT - E3 Cosmologie
3 UPV / EHU - University of the Basque Country = Euskal Herriko Unibertsitatea
4 ICE-CSIC - Institut de Ciencies de l'Espai [Barcelona]
5 Institute of Physics [Szczecin]

In this work we consider a family of cosmological models featuring future singularities. This type of cosmological evolution is typical of dark energy models with an equation of state violating some of the standard energy conditions (e.g. the null energy condition). Such kind of behavior, widely studied in the literature, may arise in cosmologies with phantom fields, theories of modified gravity or models with interacting dark matter/dark energy. We briefly review the physical consequences of these cosmological evolutions regarding geodesic completeness and the divergence of tidal forces in order to emphasize under which circumstances the singularities in some cosmological quantities correspond to actual singular spacetimes. We then introduce several phenomenological parameterizations of the Hubble expansion rate to model different singularities existing in the literature and use SN Ia, BAO and H(z) data to constrain how far in the future the singularity needs to be (under some reasonable assumptions on the behaviour of the Hubble factor). We show that quite generally, the lower bound for the singularity time can not be smaller than about 1.2 times the age of the universe, what roughly speaking means ∼ 2.8 Gyrs from the present time.

Domaines: Physique [physics]; Relativité Générale et Cosmologie Quantique [gr-qc]

Jose Beltrán Jiménez, Ruth Lazkoz, Diego Sáez-Gómez, Vincenzo Salzano. Observational constraints on cosmological future singularities. European Physical Journal C: Particles and Fields, 2016, 76 (11), pp.631. ⟨10.1140/epjc/s10052-016-4470-5⟩. ⟨hal-01282516⟩