The star that blew up was massive, probably about 20 times the mass of the Sun. When a star like that reaches the end of its life it blows a series of powerful winds of gas that surround it. Some tens of thousands of years later the core of the star collapses, setting up an immense explosion that blasts away its outer layers: Supernova.
The collapsing core of a massive star can become either a black hole or an incredibly dense neutron star. In this case, it should've formed the latter.
Video of Animation of a spinning pulsar
pulsars. They're usually pretty obvious (like a baby screaming on an airplane; the source isn't too tough to spot). But in this case, despite intense searches for over three decades, no neutron star has been found.