The unusual γ-ray burst GRB 101225A from a helium star/neutron star merger at redshift 0.33.
Thöne CC, de Ugarte Postigo A, Fryer CL, Page KL, Gorosabel J, Aloy MA, Perley DA, Kouveliotou C, Janka HT, Mimica P, et al. Nature. 2011 Nov 30; 480(7375):72-4. Epub 2011 Nov 30.