A new class of Neutron stars has been found in the Andromeda galaxy (M31), This is the first time a Spinning Neutron star has ever been detected by astronomers in M31. The article states-
“pulsars” can be found in stellar couples, with the neutron star cannibalizing its neighbor. This can lead to the neutron star spinning faster and to pulses of high-energy X-rays from hot gas being funneled down magnetic fields onto the neutron star.
“It could be what we call a ‘peculiar low-mass X-ray binary pulsar’ — in which the companion star is less massive than our Sun — or alternatively an intermediate-mass binary system with a companion of about two solar masses,” said Paolo Esposito of INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan, Italy.
While the precise nature of the system remains unclear, the data imply that it is unusual and exotic. http://www.astronomy.com/news/2016/04/andromedas-first-spinning-neutron-star-has-been-found
Question- Could the companion of this Spinning Neutron Star not be a star at all but a Black Hole? This might explain the unusual spin and that all neutron stars do not consume other binary companions stars but rather a Black Hole is in the process of consuming the neutron stars.
The Black Hole can devour all of the outer energy of any active star leaving only the dense core of heavy metals that will eventually cool off entirely creating the rouge brown dwarf. Supernovae never derived from dying neutron stars but rather from Binary star Collisions.