Signatures of minor mergers in Milky Way-like disc kinematics: Ringing revisited

Understand

By means of N-body simulations we study the response of a galactic disc to a minor merger event.

• We find that non-self-gravitating, spiral-like features are induced in the thick disc.
• As we have shown in a previous work, this "ringing" also leaves an imprint in velocity space (the u-v plane) in small spatial regions, such as the solar neighbourhood.
• As the disc relaxes after the event, clumps in the u-v plane get closer with time, allowing us to estimate the time of impact.