Magnetic fields: impact on the rotation curve of the Galaxy

Autor: Alfredo Santillán, F. J. Sánchez-Salcedo
Rok vydání: 2013
Předmět:
Zdroj: Monthly Notices of the Royal Astronomical Society. 433:2172-2181
ISSN: 1365-2966
0035-8711
DOI: 10.1093/mnras/stt880
Popis: We quantify the effects of magnetic fields, cosmic rays and gas pressure on the rotational velocity of HI gas in the Milky Way, at galactic distances between Rsun and 2Rsun. The magnetic field is modelled by two components; a mainly azimuthal magnetic component and a small-scale tangled field. We construct a range of plausible axisymmetric models consistent with the strength of the total magnetic field as inferred from radio synchrotron data. In a realistic Galactic disk, the pressure by turbulent motions, cosmic rays and the tangled turbulent field provide radial support to the disk. Large-scale (ordered) magnetic fields may or may not provide support to the disk, depending on the local radial gradient of the azimuthal field. We show that for observationally constrained models, magnetic forces cannot appreciably alter the tangential velocity of HI gas within a galactic distance of 2Rsun.
11 pages, 8 figures, accepted for publication in MNRAS
Databáze: OpenAIRE