Dark halos of M31 and the Milky Way

作者：Sofue Yoshiaki^*

来源：Publications of the Astronomical Society of Japan, 2015, 67(4): 75.

DOI：10.1093/pasj/psv042

• Galaxy: fundamental parameters
• Galaxy: structure
• galaxies: dark matter
• galaxies: individual (M 31)
• galaxies: rotation curve

Grand rotation curves (GRC) within similar to 400 kpc of M31 and the Milky Way were constructed by combining disk rotation velocities and radial velocities of satellite galaxies and globular clusters. The GRC for the Milky Way was revised using the most recent solar rotation velocity. The derived GRCs were deconvolved into a de Vaucouleurs bulge, exponential disk, and a dark halo with a Navarro-Frenk-White (NFW) density profile by least-chi(2) fitting. Comparison of the best-fitting parameters revealed similarities between the disks and bulges of the two galaxies, whereas the dark-halo mass of M31 was found to be twice that of the Galaxy. We show that the NFW model may be a realistic approximation of the observed dark halos in these two giant spirals.

• 出版日期2015-8