This research journal focuses on the expected X-ray emissions from pulsars, saying that most may expect it to exhibit the “characteristic blackbody spectrum in the X-ray range”, considering how neutron stars are believed to be formed with the surface temperature of at least 107 Kelvin. Through calculations, a “limit” for the temperature of pulsars faster than the Crab pulsar NP 0532 was determined. This implies that because faster pulsars are younger and have a higher surface temperature, its radio emission will be suppressed by the Compton interaction to a greater degree. It was also stated that higher surface temperature comes with a higher density of photons, which may also suppress other radiations that might be emitted near the surface of the neutron star. This source will be very helpful towards my research question, as it focuses directly on the possible relationship between pulsar surface temperature and its (observable) periodicity / radio emission. It’s also reliable, as the journal, Nature, has an impact factor of 69.504.

This journal firstly outlines the possible differences between the mechanism of radio emissions, and X-ray, optical, infrared emissions; whether or not the same continuous spectrum (observed from the Crab pulsar) would also be observed for the pulsar radiation. The journal also listed 14 properties of radio pulses that a typical pulsar must have. Multiple proposals for the mechanisms of pulsar pulses include: High Intensity, referring to how the observed peak pulse intensity could have been enhanced by a “relativistic beaming effect”, Coherent Electron Motion and Synchrotron Radiation, Wave Amplification, and Spectrum Fluctuations. This relates to the intensity of waves, the journal also made connections with circular polarisation of the pulsars, therefore, this can be a very helpful source of information. In addition, the journal has an impact factor 69.504, meaning that it’s credible for use.

This journal was done in extension to the previous journal by Reichley and Downs (1969) as further preceding research and interpretation of the observation results in regards to the pulsar PSR 0833–45. The periodicity of the pulsar decreased by two parts per million (ppm) between February 20 and March 13, 1969. The analysed (and graphed) decay rate of the periodicity exhibited a linear pattern, which eliminates the orbital motion of the pulsar and anything involving gravitational red-shift effects from the range of possible explanations of this phenomenon. Therefore, this phenomenon can be called a “real” change in pulsation period, corresponding to an actual change in rotational period as well. The conclusion has attributed this phenomenon to a decay of angular velocity which characterises that specific pulsar.

This journal focuses on the variation in emission intensity seen in the pulsar CP 1919. The results have concluded that the reason behind these variations can be attributed to only a few factors for a long-time scale. The first possibility is that these variations may have been naturally occurring, or intrinsic, to the pulsar. Another possibility is that there is a scintillation between the pulse source on the pulsar, and the observer (Earth)... Further supported by the theory that the medium separating the pulsar and the Earth has irregular electron density sizes, which cause the emitted radio waves to diffract as it propagates through the medium. This source may prove to be very beneficial to my research, as it refers to many other valuable sources concerning the same topic, and it also has good reasoning behind theories.