Engineering topics

Stecker, F. W.

Publications and source records attributed to Stecker, F. W..

At least 181 records · Page 10

NASA NTRS1972

Ultrahigh energy photons, electrons, and neutrinos, the microwave background, and the universal cosmic-ray hypothesis

The production of ultrahigh energy photons, electrons and neutrinos as the decay products of pions produced in photomeson interactions between cosmic ray nucleons and the blackbody microwave background is discussed in terms of the resultant energy spectra of these particles. Simple asymptotic formulas are given for calculating the ultrahigh energy photon spectrum predicted for the universal cosmic ray hypothesis and the resulting spectra are compared with those obtained previously by numerical means using a different propagation equation for the photons. Approximate analytic solutions for the photon spectra are given in terms of simple power-law energy functions and slowly varying logarithmic functions.

Stecker, F. W.↗

NASA NTRS1972

Galaxy formation from annihilation-generated supersonic turbulence in the baryon-symmetric big-bang cosmology and the gamma ray background spectrum

Following the big-bang baryon symmetric cosmology of Omnes, the redshift was calculated to be on the order of 500-600. It is show that, at these redshifts, annihilation pressure at the boundaries between regions of matter and antimatter drives large scale supersonic turbulence which can trigger galaxy formation. This picture is consistent with the gamma-ray background observations discussed previously. Gravitational binding of galaxies then occurs at a redshift of about 70, at which time vortical turbulent velocities of about 3 x 10 to the 7th power cm/s lead to angular momenta for galaxies comparable with measured values.

Stecker, F. W.↗

NASA NTRS1972

Metagalactic gamma rays from relativistic-electron bremsstrahlung interactions.

Evaluation of gamma-ray spectra calculated for relativistic-electron bremsstrahlung interactions at cosmological distances under the assumption of a single power-law source spectrum for the electrons. It is concluded that such spectra cannot match the form of the observed cosmic gamma-ray spectrum above 1 MeV, as has previously been suggested.

Stecker, F. W.↗

NASA NTRS1972

Gamma-ray absorption for a beam model of NP0532.

The model involves an assessment of the effect of beaming as indicated by the pulsations themselves rather than by assuming gamma-ray absorption by interaction with an isotropic photon field. The chief absorption process to be taken into account is that of pair production in the intense photon field. Most important is the pair production in the intense photon field which occurs during the pulse.

Stecker, F. W.↗

NASA NTRS1972

Theoretical implications of gamma-ray astronomy

The measurement of cosmic gamma rays above 100 MeV by OSO-3 satellite and those from 1 to 6 MeV measured by the ERS-18 satellite are summarized.

Stecker, F. W.↗

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

Possible evidence for the existence of antimatter on a cosmological scale in the universe.

Initial results of a detailed calculation of the cosmological gamma-ray spectrum from matter-antimatter annihilation in the universe. The similarity between the calculated spectrum and the present observations of the gamma-ray background spectrum above 1 MeV suggests that such observations may be evidence of the existence of antimatter on a large scale in the universe.

Stecker, F. W.↗

NASA NTRS1971

Origin and composition of ultrahigh energy cosmic rays.

Suggestion that, under certain circumstances, the absence of an apparent flattening of the ultrahigh energy cosmic ray spectrum at an energy level above 3 x 10 to the 18th power eV may have implications concerning the origin of ultrahigh energy cosmic rays (UECR). On the basis of the discussion presented, it seems that a heavy composition is indicated. It is therefore concluded that recent air-shower studies seem to indicate the resurrection of the galactic origin model.

Stecker, F. W.↗

NASA NTRS1971