http://arxiv.org/abs/1806.02832
The second data release from ESA’s Gaia mission has revealed many ridge-like structures in the velocity distribution of the Milky Way. We show that these can arise naturally from winding transient spiral structure that is commonly seen in N-body simulations of disk galaxies. We construct analytic models of the winding spiral structure, and compare the resulting distribution of orbits with the observed two-dimensional velocity distribution in the extended solar neighbourhood and with the distribution of rotational velocities over 8 kpc along the Sun-Galactic-centre-Galactic anti-centre line. We show that the ridges in these observations are well reproduced by the winding spiral model. Additionally, we demonstrate that the transient winding spiral potential can create a Hercules-like feature in the kinematics of the Solar neighbourhood, either alone, or in combination with a long-slow bar potential.
J. Hunt, J. Hong, J. Bovy, et. al.
Mon, 11 Jun 18
19/50
Comments: 10 pages, 6 figures, submitted to MNRAS