Testing alternative theories of dark matter with the CMB

Baojiu Li, John D. Barrow, David F. Mota, Hongsheng Zhao

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

We propose a method to study and constrain modified gravity theories for dark matter using CMB temperature anisotropies and polarization. We assume that the theories considered here have already passed the matter power-spectrum test of large-scale structure. With this requirement met, we show that a modified gravity theory can be specified by parametrizing the time evolution of its dark-matter density contrast, which is completely controlled by the dark-matter stress history. We calculate how the stress history with a given parametrization affects the CMB observables, and a qualitative discussion of the physical effects involved is supplemented with numerical examples. It is found that, in general, alternative gravity theories can be efficiently constrained by the CMB temperature and polarization spectra. There exist, however, special cases where modified gravity cannot be distinguished from the CDM model even by using both CMB and matter power spectrum observations, nor can they be efficiently restricted by other observables in perturbed cosmologies. Our results show how the stress properties of dark matter, which determine the evolutions of both density perturbations and the gravitational potential, can be effectively investigated using just the general conservation equations and without assuming any specific theoretical gravitational theory within a wide class.

Original languageEnglish
Pages (from-to)064021
Number of pages14
JournalPhysical review. D, Particles, fields, gravitation, and cosmology
Volume78
Issue number6
DOIs
Publication statusPublished - Sept 2008

Keywords

  • MICROWAVE BACKGROUND ANISOTROPIES
  • GAUGE-INVARIANT APPROACH
  • NEWTONIAN DYNAMICS
  • GRAVITY
  • GALAXIES
  • ENERGY
  • MODELS
  • POLARIZATION
  • CONSTRAINTS
  • COVARIANT

Fingerprint

Dive into the research topics of 'Testing alternative theories of dark matter with the CMB'. Together they form a unique fingerprint.

Cite this