Intrinsic Kicks at Birth Are Required to Explain the Observed Properties of Single and Binary Neutron Stars

The single assumption that neutron stars receive a kick velocity at their formation explains a large variety of observations, ranging from observed properties of individual binary radio pulsars and Be/X-ray binaries to the observed birth rates and dynamical properties of the populations of low-mass X-ray binaries and recycled radio pulsars. The rejection of this one assumption by Iben & Tutukov compels them to introduce a considerable number of ad hoc hypotheses, each explaining a only small part of the observational results. We conclude that the choice of the single powerful assumption that neutron stars receive a kick velocity at their formation is highly preferable.