The evolution of the γ- and X-ray luminosities of pulsar wind nebulae.
MATTANA F., FALANGA M., GOTZ D., TERRIER R., ESPOSITO P., PELLIZZONI A., DE LUCA A., MARANDON V., GOLDWURM A. and CARAVEO P.A.
Abstract (from CDS):
Pulsar wind nebulae (PWNe) are a prominent class of very high energy (E > 0.1 TeV) Galactic sources. Their γ-ray spectra are interpreted as due to inverse Compton scattering of ultrarelativistic electrons on the ambient photons, whereas the X-ray spectra are due to synchrotron emission. We investigate the relation between the γ- and X-ray emission and the pulsars' spin-down luminosity and characteristic age. We find that the distance-independent γ-ray to X-ray flux ratio of the nebulae is inversely proportional to the spin-down luminosity, (), while it appears proportional to the characteristic age, (∝τ2.2c), of the parent pulsar. We interpret these results as due to the evolution of the electron energy distribution and the nebular dynamics, supporting the idea of so-called relic PWNe. These empirical relations provide a new tool to classify unidentified diffuse γ-ray sources and to estimate the spin-down luminosity and characteristic age of rotation-powered pulsars with no detected pulsation from the X-ray and γ-ray properties of the associated PWNe. We apply these relations to predict the spin-down luminosity and characteristic age of four (so far unpulsing) candidate pulsars associated with wind nebulae.