Radiation efficiencies of the pulsars (current update).

Mar 28, 2014, 2:15 PM


Sergey Zharikov


Eighteen pulsars with optical counterparts or with significantly deep upper limits on the optical luminosity are known currently. Using available multi-wavelength data for these pulsars we reanalyze the efficiencies of the conversion of the pulsar spin-down power into the observed non-thermal luminosity L in different spectral domains. This sample of pulsars confirms the non-monotonic evolution of the pulsar radiation efficiency in the optical and X-ray domains (Zharikov et al. 2006). There is a clear evidence of a change in the behavior of the optical and X-ray efficiencies around ~ 10^4 years. Optical and X-ray efficiencies initially decrease before starting to flatten or increase at larger ages. The timescale ~10^4 years is comparable to the transition between neutrino and photon cooling stage (Yakovlev et al. 2004, and references therein) in neutron stars. The change of the cooling stage probably affects the distribution of relativistic particles in the pulsar magnetosphere, which is reflected in the dependence of the optical/X-ray efficiency on the pulsar age. The slopes of the time evolution of optical and X-ray efficiencies after 10^4 years are practically similar and compatible with that of radio efficiency.

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