Comparison of multiwavelength observations of 9 broad-band pulsars with
  the spectrum of the emission from an extended current with a superluminally
  rotating distribution pattern
  The observed spectra of 9 pulsars for which multiwavelength data are
available from radio to $X$- or $\gamma$-ray bands (Crab, Vela, Geminga,
B0656+14, B1055-52, B1509-58, B1706-44, B1929+10, and B1951+32) are compared
with the spectrum of the radiation generated by an extended polarization
current whose distribution pattern rotates faster than light {\it in vacuo}. It
is shown that by inferring the values of two free parameters from observational
data (values that are consistent with those of plasma frequency and electron
cyclotron frequency in a conventional pulsar magnetosphere), and by adjusting
the spectral indices of the power laws describing the source spectrum in
various frequency bands, one can account {\em quantitatively} for the entire
spectrum of each pulsar in terms of a single emission process. This emission
process (a generalization of the synchrotron-\'Cerenkov process to a
volume-distributed source in vacuum) gives rise to an oscillatory radiation
spectrum. Thus, the bell-shaped peaks of pulsar spectra in the ultraviolet or
$X$-ray bands (the features that are normally interpreted as manifestations of
thermal radiation) appear in the present model as higher-frequency maxima of
the same oscillations that constitute the emission bands observed in the radio
spectrum of the Crab pulsar. Likewise, the sudden steepening of the gradient of
the spectrum by -1, which occurs around $10^{18}-10^{21}$ Hz, appears as a
universal feature of the pulsar emission: a feature that reflects the transit
of the position of the observer across the frequency-dependent Rayleigh
distance. Inferred values of the free parameters of the present model suggest,
moreover, that the lower the rotation frequency of a pulsar, the more weighted
towards higher frequencies will be its observed spectral intensity.
