SIMBAD references

In light of the recently discovered neutron star populations, we discuss the various estimates for the birthrates of these populations. We revisit the question as to whether the Galactic supernova rate can account for all of the known groups of isolated neutron stars. After reviewing the rates and population estimates, we find that if the estimates are in fact accurate, the current birthrate and population estimates are not consistent with the Galactic supernova rate. We discuss possible solutions to this problem including whether or not some of the birthrates are hugely overestimated. We also consider a possible evolutionary scenario between some of the known neutron star classes which could solve this potential birthrate problem.