Magnetic fields and the outer rotation curve of M31

Abstract

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.

Accepted for publication in ApJL

References in corpus (10)

• High-Resolution Rotation Curves and Galaxy Mass Models from THINGS
• Magnetism in the spiral galaxy NGC 6946: magnetic arms, depolarization rings, dynamo modes and helical fields
• HI kinematics and dynamics of Messier 31
• GHASP : an H alpha kinematic survey of spiral and irregular galaxies. V. Dark matter distribution in 36 nearby spiral galaxies
• A wide-field HI mosaic of Messier 31. II.The disk warp, rotation and the dark matter halo
• The mass distribution in early-type disk galaxies: declining rotation curves and correlations with optical properties
• A Wide-field High Resolution HI Mosaic of Messier 31: I. Opaque Atomic Gas and Star Formation Rate Density
• Dark and Baryonic Matter in Bright Spiral Galaxies: II. Radial Distributions for 34 Galaxies
• Magnetic field structures of galaxies derived from analysis of Faraday rotation measures, and perspectives for the SKA
• Darwin Tames an Andromeda Dwarf: Unraveling the Orbit of NGC 205 Using a Genetic Algorithm

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