Supernova Fallback onto Magnetars and Propeller-Powered Supernovae

Understand

We explore fallback accretion onto newly born magnetars during the supernova of massive stars.

• Strong magnetic fields (~10^{15} G) and short spin periods (~1-10 ms) have an important influence on how the magnetar interacts with the infalling material.
• At long spin periods, weak magnetic fields, and high accretion rates, sufficient material is accreted to form a black hole, as is commonly found for massive progenitor stars.
• When B<5*10^{14} G, accretion causes the magnetar to spin sufficiently rapidly to deform triaxially and produce gravitational waves, but only for ~50-200 s until it collapses to a black hole.