The Galactic population and properties of young, highly-energetic pulsars

The population of young, non-recycled pulsars with spin-down energies |$\dot{E} \gt 10^{35}$| erg s^−1 is sampled predominantly at γ-ray and radio wavelengths. A total of 137 such pulsars are known, with partial overlap between the sources detectable in radio and γ-rays. We use a very small set of assumptions in an attempt to test whether the observed pulsar sample can be explained by a single underlying population of neutron stars. For radio emission we assume a canonical conal beam with a fixed emission height of 300 km across all spin periods and a luminosity law which depends on |$\dot{E}^{0.25}$|⁠. For γ-ray emission we assume the outer-gap model and a luminosity law which depends on |$\dot{E}^{0.5}$|⁠. We synthesize a population of fast-spinning pulsars with a birth rate of one per 100 yr. We find that this simple model can reproduce most characteristics of the observed population with two caveats. The first is a deficit of γ-ray pulsars at the highest |$\dot{E}$| which we surmise to be an observational selection effect due to the difficulties of finding γ-ray pulsars in the presence of glitches without prior knowledge from radio frequencies. The second is a deficit of radio pulsars with interpulse emission, which may be related to radio emission physics. We discuss the implications of these findings