We present predictions for the line-of-sight velocity dispersion profiles of dwarf spheroidal galaxies and compare them to observations in the case of the Fornax dwarf .
The predictions are made in the framework of standard dynamical theory of spherical systems with different velocity distributions .
The stars are assumed to be distributed according to Sérsic laws with parameters fitted to observations .
We compare predictions obtained assuming the presence of dark matter haloes ( with density profiles adopted from N -body simulations ) versus those resulting from Modified Newtonian Dynamics ( MOND ) .
If the anisotropy of velocity distribution is treated as a free parameter observational data for Fornax are reproduced equally well by models with dark matter and with MOND .
If stellar mass-to-light ratio of 1 M _ { \sun } / L _ { \sun } is assumed , the required mass of the dark halo is 1.5 \times 10 ^ { 9 } M _ { \sun } , two orders of magnitude bigger than the mass in stars .
The derived MOND acceleration scale is a _ { 0 } = 2.1 \times 10 ^ { -8 } cm/s ^ { 2 } .
In both cases a certain amount of tangential anisotropy in the velocity distribution is needed to reproduce the shape of the velocity dispersion profile in Fornax .