N. R. Napolitano, S. Capozziello, A. J. Romanowsky, M. Capaccioli, C. Tortora
We present the first analysis of extended stellar kinematics of elliptical
galaxies where a Yukawa--like correction to the Newtonian gravitational
potential derived from f(R)-gravity is considered as an alternative to dark
matter. In this framework, we model long-slit data and planetary nebulae data
out to 7 Re of three galaxies with either decreasing or flat dispersion
profiles. We use the corrected Newtonian potential in a dispersion-kurtosis
Jeans analysis to account for the mass-anisotropy degeneracy. We find that
these modified potentials are able to fit nicely all three elliptical galaxies
and the anisotropy distribution is consistent with that estimated if a dark
halo is considered. The parameter which measures the "strength" of the
Yukawa-like correction is, on average, smaller than the one found previously in
spiral galaxies and correlates both with the scale length of the Yukawa-like
term and the orbital anisotropy.
View original:
http://arxiv.org/abs/1201.3363
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