Radiation Burst by Axion Star Collision with Star in the Andromeda Galaxy

Understand

Axion is a promising candidate of dark matter in the universe.

• A fraction of dark matter axion may forms axion star with radius $\sim 10^2$km.
• We show that the axion star emits radiation burst by the collision with K and M types main sequence star in the Andromeda Galaxy.
• The emission arises in the atmosphere of the star, in which electrons coherently oscillate due to oscillating electric field of the axion star.