Generalized virial theorem in f(R) gravity

Abstract

We generalize the virial theorem in f(R) modified gravity using the collisionless Boltzmann equation. We find supplementary geometric terms in the modified Einstein equation providing an effective contribution to the gravitational energy. The total virial mass is proportional to the effective mass associated with the new geometrical term, which may account for the well-known virial theorem mass discrepancy in clusters of galaxies. The model predicts that the geometric mass and its effects extend beyond the virial radius of the clusters. We also consider the behavior of the galaxy cluster velocity dispersion in f(R) models. Thus, the f(R) virial theorem can be an efficient tool in observationally testing the viability of this class of generalized gravity models.

12 pages; references added, minor changes, accepted for publication in JCAP

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Cited by in corpus (4)

• The future evolution and finite-time singularities in $F(R)$-gravity unifying the inflation and cosmic acceleration
• Dark matter as a geometric effect in f(R) gravity
• Thin accretion disks in f(R) modified gravity models
• Dark energy, inflation and dark matter from modified F(R) gravity