Linear growth of structure in massive bigravity
2014 (English)In: Journal of Cosmology and Astroparticle Physics, ISSN 1475-7516, Vol. 2014, no 10, 066- p.Article in journal (Refereed) Published
The ghost-free theory of massive gravity with two dynamical metrics has been shown to produce viable cosmological expansion, where the late-time acceleration of the Universe is due to the finite range of the gravitational interaction rather than a nonzero cosmological constant. Here the cosmological perturbations are studied in this theory. The full perturbation equations are presented in a general gauge and analyzed, focusing on subhorizon scales in the quasistatic limit during the matter-dominated era. An evolution equation for the matter inhomogeneities and the parameters quantifying the deviations from general relativistic structure formation are expressed in terms of five functions whose forms are determined directly by the coupling parameters in the theory. The evolution equation has a similar structure to Horndeski-type scalar-tensor theories, exhibiting a modified growth rate and scale-dependence at intermediate wavenumbers. Predictions of the theory are confronted with observational data on both background expansion and large-scale structure, although care must be taken to ensure a model is stable. It is found that while the stable models tit the data well, they feature deviations from the standard cosmology that could be detected or ruled out by near-future experiments.
Place, publisher, year, edition, pages
2014. Vol. 2014, no 10, 066- p.
modified gravity, cosmological parameters from LSS, cosmological perturbation theory, dark energy theory
Astronomy, Astrophysics and Cosmology
IdentifiersURN: urn:nbn:se:kth:diva-158453DOI: 10.1088/1475-7516/2014/10/066ISI: 000345990800067ScopusID: 2-s2.0-84908513346OAI: oai:DiVA.org:kth-158453DiVA: diva2:777062
FunderEU, European Research Council, StG2010-257080
QC 201501082015-01-082015-01-082015-01-08Bibliographically approved