On the maximum mass of differentially rotating neutron stars

We construct relativistic equilibrium models of differentially rotating neu tron stars and show that they can support significantly more mass than thei r nonrotating or uniformly rotating counterparts. We dynamically evolve suc h "hypermassive" models in full general relativity and show that there do e xist configurations that are dynamically stable against radial collapse and bar formation. Our results suggest that the remnant of binary neutron star coalescence may be temporarily stabilized by differential rotation, leadin g to delayed collapse and a delayed gravitational wave burst.