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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 955 records · Page 53
All sourcesNASA NTRSDOE OSTI
NASA NTRS1969

X-ray pulsar in the Crab Nebula.

X ray pulsations in Crab Nebula at frequency closely matching radio and optical pulsations, noting energy distribution

Chubb, T. A.↗
NASA NTRS1969

Pulsar emission mechanism.

Radiation emission mechanism for NP 0532 associated with Crab Nebula, discussing shock- neutral sheet interaction

Michel, F. C.↗
NASA NTRS1971

Gamma-ray absorption for a beam model of the Crab nebula pulsar NP0532

A model is discussed for determining gamma ray absorption from NP0532 by estimating the effect of beaming as indicated by the pulsations. The main absorption process is considered to be that of pair production in the intense photon field which occurs during the pulse. The results indicate that for this model, absorption does not occur below 10 GeV.

Stecker, F. W.↗
NASA NTRS1971

Observation of Pulsed Gamma Rays with Energies Greater than 250 keV from the Crab Nebula Pulsar NP 0532

Data from a balloon flight experiment using an Na I scintillation spectrometer were analyzed for gamma ray pulsation. The payload was carried to a nominal atmospheric depth of 3.5 g/cm2. A superposed epoch analysis was performed on a 12,000 second portion of the data spanning a total time interval of 16,700 seconds at float altitude. A positive pulsed contribution was observed at the expected apparent frequency of NP 0532 having the typical double pulse structure. The results indicate a time-averaged pulse photon flux of 0.00144 + or - 0.00057 photons/sq cm/sec in the energy interval from 250 keV to 2.3 MeV. This represents a time-averaged pulsed power of 0.000649 + or - 0.000257 keV/sq cm/sec/keV. The ratio of interpulse to main pulse was found to be 2.4 + or - 1.9. The analysis indicates a positive photon flux from 250 keV to 725 keV of 0.00120 + or - 0.00052 photons/sq cm/sec.

Orwig, L. E.↗
NASA NTRS1972

X-ray observations of pulsars.

The X-ray pulsations from NP 0532, discovered by Fritz et al. (1969), have been studied. The detectors in the investigations had wide fields of view, and the entire Crab Nebula NP 0532 radiation was detected. The power density spectrum of X-radiation observed is presented together with the shapes of X-ray and optical pulses. Searches for X-ray pulsations from other X-ray sources have also been carried out. The summarized results are shown in a table.

Bradt, H. V.↗
NASA NTRS1971

Measurement of the circular polarization of pulsar NP 0532.

The polarizer is briefly described. The polarization of the whole pulse is not significantly different from zero (-0.15 plus or minus 0.70 per cent). Polarization measurements of the leading edge and trailing edge of the main pulse are also given.

Angel, J. R. P.↗
NASA NTRS1973

Pulsar magnetospheres, braking index, polar caps, and period-pulse-width distribution.

An investigation is conducted concerning the trapping of gas and its effect on the structure of the magnetic field. The aligned and orthogonal cases are discussed in detail. In each case, there are small collection zones which are both microscopically and macroscopically stable. By determining where macroscopic stability changes to instability, the separatrix between closed and open field lines is investigated together with the sizes and shapes of the polar caps. This information makes it possible to reexamine the period-pulse-width distribution and to compare it with observational data.

Roberts, D. H.↗
NASA NTRS1974

Analytic pulsar models

An analytical procedure is given for solving the Einstein equations of a rotating fluid body. It is demonstrated that an analytic model of uniform denisty, representing a slowly rotating neutron star, can describe both differentially and uniformly rotating stars.

Adams, R. C.↗