Time variability of the dispersion of the Crab Nebula pulsar
Time variable dispersion of Crab Nebula pulsar, showing coincidence with occultation by solar corona
Rankin, J. M.↗
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Timing observations of the Crab Nebula pulsar at the Arecibo Observatory
Crab Nebula pulsar timing observations, correcting arrival times to solar system barycenter and dispersion effect
Richards, D. W.↗
Multiple pulsar ejection in supernova events
Multiple pulsar ejection in supernova core collapse and neutron star formation energy loss
Michel, F. C.↗
Maser theory of pulsar radiation
Pulsar radio emission via maser amplification, presenting model based on electrons behavior in intense magnetic field
Chiu, H.-Y.↗
Radiation beaming in pulsars
Pulsar radiation beaming due to strong magnetic field, computing Compton scattering and opacity
Canuto, V.↗
Crab Nebula pulsar radio pulse arrival times at Arecibo Observatory
Tables of Crab Nebula pulsar radio pulse arrival times at Arecibo observatory
Counselman, C. C., III↗
On the absorption of gamma rays by photons in pulsars, quasi-stellar objects, and other source objects
Quasar and pulsar gamma ray absorption by critical energy collisions with low energy photons
Guthrie, P. D.↗
Tests of general relativity using pulsars
The arrival times of the pulses from each pulsar are measured by a cesium clock. The observations are all made at a frequency of 2388 MHz (12.5 cm wavelength) on a 26 m dish antenna. The effect of interstellar charged particles is a random one that increases the noise level on the arrival time measurements. The variation in clock rate is shown consisting of two effects: the time dilation effect of special relativity and the red shift effect of general relativity.
Reichley, P. E.↗
Production of gamma rays in the crab nebula pulsar
The gamma-ray flux at energies above 50 MeV from NP0532 is evaluated for a pulsar model in which the optical and X-radiation is produced by synchrotron effect. Synchrotron radiation and inverse Compton scattering are considered as production mechanisms of the gamma-rays. The theoretical estimates are compared with the experimental values.
Treves, A.↗
Importance of pulsar observations for planetary physics
The possibility of observing the planetary systems of pulsars is examined. The expected perturbation in the time of arrival of pulses is computed and the detectability is discussed.
Treves, A.↗
Cooling of pulsars
Cooling rates are calculated for superfluid neutron stars of about one solar mass and 10 km radius, with magnetic fields from zero to about 10 to the 14th power Gauss, when possible internal friction effects are neglected. The results show that most old pulsars are so cold that thermal ionization of surface atoms would be negligible. At an age of a million years and with canonical magnetic fields of 10 to the 12th power Gauss, the estimated stellar surface temperature is several thousand to a hundred thousand degrees. However, if we neglect magnetic fields and superfluid states of nucleons, the same surfaces would be about a million degrees.
Tsuruta, S.↗
Algebraically special space-time in relativity, black holes, and pulsar models
The entire field of astronomy is in very rapid flux, and at the center of interest are problems relating to the very dense, rotating, neutron stars observed as pulsars. the hypothesized collapsed remains of stars known as black holes, and quasars. Degenerate metric form, or Kerr-Schild metric form, was used to study several problems related to intense gravitational fields.
Adler, R. J.↗
Quasars, pulsars, black holes and HEAO's
Astronomical surveys are discussed by large X-ray, gamma ray, and cosmic ray instruments carried onboard high-energy astronomy observatories. Quasars, pulsars, black holes, and the ultimate benefits of the new astronomy are briefly discussed.
Doolitte, R. F.↗
Optical radiation from the Crab pulsar
Possible mechanisms for producing the optical radiation from the Crab pulsar are proposed and discussed. There are severe difficulties in interpreting the radiation as being produced by an incoherent process, whether it be synchrotron radiation, inverse-Compton radiation or curvature radiation. It is proposed therefore that radiation in the optical part of the spectrum is coherent. In the polar cap model, a small bunch of electrons and positrons forms near each primary electron as a result of the pair-production cascade process. Ambient electric fields give rise to energy separation, as a result of which either the electrons or positrons will dominate the radiation from each bunch. The roll-off in the infrared is ascribed to synchrotron absorption by electrons and positrons located between the surface of the star and the force-balance radius. Various consequences of this model, which may be subjected to observational test, are discussed.
Sturrock, P. A.↗
Cosmic-ray generation by pulsars
Electromagnetic and particle energy fluxes are equipartitioned in a superrelativistic plasma wave. The consequences for cosmic-ray acceleration by pulsars are investigated.
Kennel, C. F.↗
Individual pulse polarization properties of three pulsars
Both average and individual pulse polarization measurements at 430 MHz are presented for three pulsars: PSR 0823 + 26, PSR 0834 + 06, and PSR 2303 + 30. In each case, the average Stokes parameter waveformes are found to depend on the individual pulse polarization properties in a complicated manner. The average waveforms are in general depolarized by pulse-to-pulse fluctuations in polarization state at a given longitude. Two of the three objects exhibit variations of both linear and circular polarization which are associated with quasi-periodic subpulse modulation phenomena in a manner similar to that reported for linear polarization in PSR 0809 + 74 by Taylor et al. (1971.).
Rankin, J. M.↗
Interstellar scattering of pulsar radiation. 1: Scintillation
An investigation of the intensity fluctuations of 28 pulsars near 0.4 GHz indicates that scintillation spectra have a Gaussian shape, scintillation indices are near unity, and the scintillation bandwidth depends linearly on dispersion measure. Observations near 2.5 GHz suggest a strong dependence of the frequency at which scintillation indices fall below unity on dispersion measure. Multistation measurements of scintillation provide values or limits for the scale size of the scattering diffraction pattern. The dependences of scattering parameters on dispersion measure is discussed in terms of the current models. It is suggested that any line of sight through the galaxy encounters increasingly rare, increasingly large deviations of thermal electron density on the scale of 10 to the 11th power cm.
Backer, D. C.↗
The 1973 solar occultation of the Crab Nebula pulsar
The mean electron density of the solar corona was determined by measuring the dispersion of radiofrequency pulses from pulsar NP 0532 during the June 1973 solar occultation. Trends continued which were noticed in 1971 as solar activity declined. Model fitting results suggest that the corona continued to become even more concentrated toward the equator in 1973 than in 1971. The number density of electrons in most regions decreased. The best model of the distribution of corona electrons is suggested to be one with zero density at the poles. K-corona isophotes and contours of equal path-integrated density are presented for several models. Electron density versus date and position in the corona are tabulated. It is seen that there is no simple relationship between the onset of major solar activity and density or scattering enhancements.
Weisberg, J. M.↗