Detalles de publicación
PP 010070
Magnetic fields and the outer rotation curve of M31
(1) IAC, (2) Departamento de Física Teórica y del Cosmos, Universidad de Granada, (3) Instituto de Física Teórica y Computacional Carlos I, Granada.
Recent observations of the rotation curve of M31 show a rise of the outer part that can not
be understood in terms of standard dark matter models or perturbations of the galactic disc
by M31’s satellites. Here, we propose an explanation of this dynamical feature based on the
influence of the magnetic field within the thin disc. We have considered standard mass models
for the luminous mass distribution, a NFW model to describe the dark halo, and we have added
up the contribution to the rotation curve of a magnetic field in the disc, which is described by
an axisymmetric pattern. Our conclusion is that a significant improvement of the fit in the outer
part is obtained when magnetic effects are considered. The best-fit solution requires an amplitude
of ∼ 4 microG with a weak radial dependence between 10 and 38 kpc.
be understood in terms of standard dark matter models or perturbations of the galactic disc
by M31’s satellites. Here, we propose an explanation of this dynamical feature based on the
influence of the magnetic field within the thin disc. We have considered standard mass models
for the luminous mass distribution, a NFW model to describe the dark halo, and we have added
up the contribution to the rotation curve of a magnetic field in the disc, which is described by
an axisymmetric pattern. Our conclusion is that a significant improvement of the fit in the outer
part is obtained when magnetic effects are considered. The best-fit solution requires an amplitude
of ∼ 4 microG with a weak radial dependence between 10 and 38 kpc.