34
1 Introduction to the Pulsars
why the pulse periods may be recovered to the normal level before the glitches is
unable to be explained convincingly. Another view is that the glitches result from a
kind of complex orbital motions. The glitches are not irregular, but the regularities
are very complicated and can not be understood by the human beings yet.
No matter what kind of the interpretations, it is necessary to verify them by the
long-term observational data. The typical glitches occur at average interval of several
years. The stable periodicity of pulsar can not be kept during several months after
the glitch. And thereby, it is a long-term task to monitor and investigate the glitches.
For the application of the XPNAV, the pulsars should continuously be monitored and
predicted, and once the glitches happen, the corresponding pulsars will be isolated
from the pulsar navigation database. After recovering to the normal periods, the
pulsars are again put into the database.
1.5.3 Radiant Energy Spectrum
The radiant energy spectrum of pulsars is a non-thermal radiation with a power-law
spectrum, and can be expressed as
E = E 0 ν
α
,
(1.8)
where E is the radiant energy, ν is the radiant frequency, and α is the power exponent,
with a typical value of −1.5.
The power-law spectrums of radiant energies are typical characteristics of the
synchrotron and curvature radiations from high-energy electrons. Moreover, the
radiant features of high polarizations are also observed. Many pulsars have very
high linear polarizations whose intensities are far greater than circular polarizations. Certainly, the power-law spectrums are also necessary results of the radiations
from highly rapid rotation neutron stars with extremely strong magnetic fields. The
charged particles (mainly containing electrons) can be accelerated by rapidly rotating
strong magnetic fields and they obtain higher energies; when the electrons make
spiral motion around the magnetic field lines or accelerated motion along them, the
synchrotron and curvature radiations with the power-law spectrum will be produced.
It is generally considered that the magnetic field strengths at two magnetic poles
are strong, and thus the radiations mainly concentrate on the magnetic axis and
form two beams with contrary direction. Furthermore, it is also considered that the
magnetic axis and the rotation axis do not coincide, and thereby the radiant beams
emitted along the magnetic axis will form the lighthouse effects. Obviously, Issue on
the power-law spectrum distribution of the radiant energy can be well explained by
utilizing the magnetic dipole model of pulsars. However, it is difficult that the radiations with the power-law spectrum are reasonably explained by using the pulsating
model of pulsars. So, the pulsating model is also eliminated from the theoretic models
of pulsars.
1 Introduction to the Pulsars
why the pulse periods may be recovered to the normal level before the glitches is
unable to be explained convincingly. Another view is that the glitches result from a
kind of complex orbital motions. The glitches are not irregular, but the regularities
are very complicated and can not be understood by the human beings yet.
No matter what kind of the interpretations, it is necessary to verify them by the
long-term observational data. The typical glitches occur at average interval of several
years. The stable periodicity of pulsar can not be kept during several months after
the glitch. And thereby, it is a long-term task to monitor and investigate the glitches.
For the application of the XPNAV, the pulsars should continuously be monitored and
predicted, and once the glitches happen, the corresponding pulsars will be isolated
from the pulsar navigation database. After recovering to the normal periods, the
pulsars are again put into the database.
1.5.3 Radiant Energy Spectrum
The radiant energy spectrum of pulsars is a non-thermal radiation with a power-law
spectrum, and can be expressed as
E = E 0 ν
α
,
(1.8)
where E is the radiant energy, ν is the radiant frequency, and α is the power exponent,
with a typical value of −1.5.
The power-law spectrums of radiant energies are typical characteristics of the
synchrotron and curvature radiations from high-energy electrons. Moreover, the
radiant features of high polarizations are also observed. Many pulsars have very
high linear polarizations whose intensities are far greater than circular polarizations. Certainly, the power-law spectrums are also necessary results of the radiations
from highly rapid rotation neutron stars with extremely strong magnetic fields. The
charged particles (mainly containing electrons) can be accelerated by rapidly rotating
strong magnetic fields and they obtain higher energies; when the electrons make
spiral motion around the magnetic field lines or accelerated motion along them, the
synchrotron and curvature radiations with the power-law spectrum will be produced.
It is generally considered that the magnetic field strengths at two magnetic poles
are strong, and thus the radiations mainly concentrate on the magnetic axis and
form two beams with contrary direction. Furthermore, it is also considered that the
magnetic axis and the rotation axis do not coincide, and thereby the radiant beams
emitted along the magnetic axis will form the lighthouse effects. Obviously, Issue on
the power-law spectrum distribution of the radiant energy can be well explained by
utilizing the magnetic dipole model of pulsars. However, it is difficult that the radiations with the power-law spectrum are reasonably explained by using the pulsating
model of pulsars. So, the pulsating model is also eliminated from the theoretic models
of pulsars.