Radio Signals from Axion Star-Neutron Star Binaries

Understand

Axion stars could form binaries with neutron stars.

• Given the extremely strong external magnetic field exhibited by individual neutron stars, there can be a substantial conversion of axions to photons in these binaries.
• The photon emission is doubly modulated due to the neutron star spinning and the axion star orbiting, yielding a unique discovery signal.
• Similar features are also generated in binaries between a neutron star and an axion-clouded black hole.