Starquakes in millisecond pulsars and gravitational waves emission

Understand

So far, only transient Gravitational waves (GWs) produced by catastrophic events of extra-galactic origin have been detected.

• However, it is generally believed that there should be also continuous sources of GWs within our galaxy, such as accreting neutron stars (NSs).
• In fact, in accreting NSs, centrifugal forces can be so strong to break the neutron star crust (causing a starquake), thus producing a quadrupole moment responsible for the continuous emission of GWs.
• At equilibrium, the angular momentum gained by accretion and lost via GWs emission should balance each other, stopping the stellar spin-up.