Dark matter dominated dwarf disc galaxy Segue 1 - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado




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Abstract: Several observations reveal that dwarf galaxy Segue 1 has a dark matter DMhalo at least ~ 200 times more massive than its visible baryon mass of only ~103 solar masses. The baryon mass is dominated by stars with perhaps aninterstellar gas mass of < 13 solar masses. Regarding Segue 1 as a dwarf discgalaxy by its morphological appearance of long stretch, we invoke the dynamicmodel of Xiang-Gruess, Lou and Duschl XLD to estimate its physical parametersfor possible equilibria with and without an isopedically magnetized gas disc.We estimate the range of DM mass and compare it with available observationalinferences. Due to the relatively high stellar velocity dispersion compared tothe stellar surface mass density, we find that a massive DM halo would benecessary to sustain disc equilibria. The required DM halo mass agrees grosslywith observational inferences so far. For an isopedic magnetic field in a gasdisc, the ratio f between the DM and baryon potentials depends strongly on themagnetic field strength. Therefore, a massive DM halo is needed to counteracteither the strong stellar velocity dispersion and rotation of the stellar discor the magnetic Lorentz force in the gas disc. By the radial force balances,the DM halo mass increases for faster disc rotation.



Autor: Meng Xiang-Gruess, Yu-Qing Lou, Wolfgang J. Duschl

Fuente: https://arxiv.org/







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