For refcode 2013MNRAS.436.1439M: Retrieve 39 NED objects in this reference. Please click here for ADS abstract
NED Abstract
Copyright by Royal Astronomical Society.
2013MNRAS.436.1439M
The MOG weak field approximation and observational test of galaxy rotation
curves
Moffat, J. W.; Rahvar, S.
Abstract. As an alternative to dark matter models, Modified Gravity (MOG)
theory is a covariant modification of Einstein gravity. The theory
introduces two additional scalar fields and one vector field. The aim is
to explain the dynamics of astronomical systems based only on their
baryonic matter. The effect of the vector field in the theory resembles a
Lorentz force where each particle has a charge proportional to its
inertial mass. The weak field approximation of MOG is derived by
perturbing the metric and the fields around Minkowski spacetime. We
obtain an effective gravitational potential which yields the Newtonian
attractive force plus a repulsive Yukawa force. This potential, in
addition to the Newtonian gravitational constant, G_N_, has two additional
constant parameters {alpha} and mu. We use The H I Nearby Galaxy Survey
catalogue of galaxies and fix the two parameters {alpha} and mu of the
theory to be {alpha} = 8.89 +/ 0.34 and mu = 0.042 +/ 0.004 kpc^1^. We
then apply the effective potential with the fixed universal parameters to
the Ursa Major catalogue of galaxies and obtain good fits to galaxy
rotation curve data with an average value of <overline>chi</overline>^2^ =
1.07. In the fitting process, only the stellar masstolight ratio (M/L)
of the galaxies is a free parameter. As predictions of MOG, our derived
M/L is shown to be correlated with the colour of galaxies. We also fit the
TullyFisher relation for galaxies. As an alternative to dark matter,
introducing an effective weak field potential for MOG opens a new window
to the astrophysical applications of the theory.
Key words: gravitation, galaxies: kinematics and dynamics, galaxies:
spiral, cosmology: theory, dark matter
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