On the Energy Spectrum of Relativistic Electrons in the Crab Nebula

1973 ◽  
Vol 183 ◽  
pp. 625 ◽  
Author(s):  
E. Tademaru
Keyword(s):  
Energy Spectrum ◽  
Crab Nebula ◽  
Relativistic Electrons ◽  
The Crab Nebula

scholarly journals On the Nature of the Emission of the Crab Nebula

1958 ◽  
Vol 8 ◽  
pp. 1047-1047
Author(s):  
I. S. Shklovsky
Keyword(s):  
Field Strength ◽  
Magnetic Energy ◽  
Crab Nebula ◽  
Central Star ◽  
Emission Sources ◽  
Relativistic Electrons ◽  
Internal Motions ◽  
The Crab Nebula ◽  
Lines Of Force

The emission of the Crab Nebula is perhaps connected with the internal motions of the gas. As shown by the observations, the power of the emission sources differs by some hundred times in different points of the amorphous mass (“wisps” and other details). Oort and Walraven believe the “wisps” to be condensations of relativistic electrons ejected from the central star. However, there are some other variable details elsewhere in the nebula (as described by Lampland, and Oort and Walraven).Oort and Walraven's hypothesis met some important difficulties: (a) the direction of the magnetic lines in this region of the nebula is perpendicular to the wisp's velocity; (b) the dimension of the wisp is about three light months, while it appears during a month and faster, so that the relativistic electrons moving along the lines of force have no time to spread along the wisp; and (c) if the strength is not changing, the energy of the relativistic electrons in the wisp must be some hundred times greater than the density of the magnetic energy, consequently the field strength must grow in the wisp to keep the electrons in the volume.

scholarly journals Transfer of Energy to the Crab Nebula Following the Spin-Up of the Pulsar

1971 ◽  
Vol 46 ◽  
pp. 296-307 ◽  
Author(s):  
D. B. Melrose
Keyword(s):  
Energy Flux ◽  
Central Region ◽  
Crab Nebula ◽  
Point Of View ◽  
Relativistic Electrons ◽  
Synchrotron Emission ◽  
X Ray ◽  
Enhanced Activity ◽  
The Crab Nebula

Observed enhanced activity in the central region of the Crab Nebula following the spin-up of the pulsar is discussed from the point of view of the transfer of energy to relativistic electrons. It is argued that a rapid deposition of energy associated with the spin-up of the pulsar causes a radial energy flux which becomes a flux in hydromagnetic activity at about the regions where enhanced synchrotron emission is observed. It is shown that such hydromagnetic activity is rapidly damped by the relativistic electrons with energy being transferred to the relativistic electrons. This acceleration can account for the short synchrotron halflifetimes observed. The model predicts highly enhanced X-ray emission from the central region of the Nebula following a spin-up.

scholarly journals Relationship Between Pulsar and Nebula

1971 ◽  
Vol 46 ◽  
pp. 389-391
Author(s):  
L. Woltjer
Keyword(s):  
Magnetic Field ◽  
Energy Density ◽  
Energy Supply ◽  
Crab Nebula ◽  
Supernova Explosion ◽  
Relativistic Electrons ◽  
The Crab Nebula ◽  
The Magnetic Field

The magnetic field and the relativistic electrons in the Crab Nebula cannot have originated at the time of the supernova explosion. The energy density in the magnetic field is so large that it must have been generated using the energy supply in the pulsar. The energies of the electrons are so high, and their lifetimes correspondingly are so short, that they must have been accelerated, again using the pulsar energy. The efficiency of these processes must be high, but there is an adequate energy supply.

scholarly journals The Nature of the Energy Source in Radio Galaxies and Active Galactic Nuclei

1982 ◽  
Vol 97 ◽  
pp. 247-253
Author(s):  
F. Pacini ◽  
M. Salvati
Keyword(s):  
Energy Source ◽  
Active Galactic Nuclei ◽  
Crab Nebula ◽  
A Priori ◽  
Galactic Nuclei ◽  
High Energy ◽  
Galactic Cosmic Rays ◽  
Relativistic Electrons ◽  
Probable Presence ◽  
The Crab Nebula

For more than 20 years it has been known that extragalactic radio sources contain up to 1060–1062 ergs in the form of relativistic electrons and magnetic fields. One arrives at these figures if one assumes that the radio emission is due to the synchrotron process and the source contains an equal amount of energy in electrons and fields (Burbidge 1956). Any deviation from the postulated equipartition increases the energy required to account for the observed luminosities. Some authors believe that the real demands on the energy source may be still higher because of the probable presence of high energy protons. The ratio Ep/Ee is determined by the way in which particles gain and lose energy, and it is impossible to estimate it a priori. Observationally one has two conflicting lines of evidence: (a) in galactic cosmic rays one measures (Ep/Ee) ≃ 102; (b) in the Crab Nebula one infers (Ep/Ee) ≲ 1 (otherwise the dynamical pressure of the proton gas would cause a nebular expansion much faster than observed).

scholarly journals High energy cosmic photons and neutrinos

1965 ◽  
Vol 23 ◽  
pp. 195-225
Author(s):  
R. J. Gould ◽  
G. R. Burbidge
Keyword(s):  
Supernova Remnants ◽  
Crab Nebula ◽  
Meson Production ◽  
Cosmic Ray ◽  
High Energy ◽  
Relativistic Electrons ◽  
X Ray ◽  
Hard Radiation ◽  
The Galaxy ◽  
The Crab Nebula

This review concentrates primarily on the problem of interpreting the recent X-ray and γ-ray observations of celestial sources. The expected fluxes of hard radiation from various processes are estimated (when possible) and are compared with the observations. We compute the synchrotron, bremsstrahlung, and (inverse) Compton spectra originating from relativistic electrons produced (via meson production) in the galaxy and intergalactic medium by cosmic ray nuclear collisions; the spectra from π°-decay are also computed. Neutron stars, stellar coronae, and supernova remnants are reviewed as possible X-ray sources. Special consideration is given to the processes in the Crab Nebula. Extragalactic objects as discrete sources of energetic photons are considered on the basis of energy requirements; special emphasis is given to the strong radio sources and the possibility of the emission of hard radiation during their formation. The problem of the detection of cosmic neutrinos is reviewed.As yet, no definite process can be identified with any of the observed fluxes of hard radiation, although a number of relevant conclusions can be drawn on the basis of the available preliminary observational results. In particular, some cosmogonical theories can be tested.

scholarly journals Synchrotron Thermal Instabilities and Radio Filaments in the Lobes of Cygnus A

1989 ◽  
Vol 8 ◽  
pp. 417-422
Author(s):  
G. Bodo ◽  
A. Ferrari ◽  
S. Massaglia ◽  
E. Trussoni
Keyword(s):  
Magnetic Field ◽  
Thermal Instability ◽  
Crab Nebula ◽  
Relativistic Electrons ◽  
Synchrotron Emission ◽  
Cygnus A ◽  
The Crab Nebula ◽  
The Magnetic Field

Recent VLA observations of the lobes of Cygnus A exhibit complex “filamentary” structures, with typical scale width ~ 1 arcsec (Dreher, Carilli and Perley, 1987, Perley, 1987). The filaments appear aligned with the magnetic field, as results from polarization measures, suggesting that the field may play a fundamental role in the process of their formation.We propose a mechanism for the possible formation of these filaments based upon a thermal instability connected with synchrotron emission from relativistic electrons. This type of instability was studied by Simon and Axford (1967), who discussed it in connection with the Crab Nebula filaments, and by Eilek and Caroff (1979), who generalized the previous study for application to quasar atmospheres.

scholarly journals The Common Properties of Plerions and Active Galactic Nuclei

1981 ◽  
Vol 94 ◽  
pp. 165-166
Author(s):  
N. Panagia ◽  
K. W. Weiler
Keyword(s):  
Supernova Remnants ◽  
Crab Nebula ◽  
Spectral Characteristics ◽  
Radio Spectrum ◽  
Brightness Distribution ◽  
Relativistic Electrons ◽  
Object A ◽  
Linearly Polarized ◽  
Bona Fide ◽  
The Crab Nebula

Plerions, i.e. supernova remnants resembling the Crab Nebula, are characterized at radio wavelengths by having: 1) a centrally peaked brightness distribution, 2) flat radio spectrum (α > −0.3, Sν να), 3) high linear polarization, and 4) a highly ordered magnetic field. At higher frequencies (1011–1013 Hz depending upon the age) the spectrum turns over and attains a slope of α ~ −1. In particular, for the Crab Nebula the turnover frequency occurs at νc ~ 3×1012 Hz (cf. Fig. 1). Moreover, the optical spectrum displays a slope of −0.9 and the radiation is linearly polarized. Nonthermal emission is also detected in the X-ray and γ-ray domains (Fig.1). Similar spectral characteristics are found for other bona fide plerions. As discussed by Weiler and Panagia (1980), the plerion phenomenon is determined by the presence of a highly energetic and active central object (a fast spinning neutron star) which is able to both accelerate and inject continuously relativistic electrons into the remnant with a typically flat energy distribution roughly proportional to E−1.

scholarly journals The Non-Thermal Continuum from the Crab Nebula: The ‘Synchro-Compton’ Interpretation

1971 ◽  
Vol 46 ◽  
pp. 407-413 ◽  
Author(s):  
M. J. Rees
Keyword(s):  
Electromagnetic Wave ◽  
Wave Field ◽  
Magnetic Dipole ◽  
Crab Nebula ◽  
Continuum Emission ◽  
Relativistic Electrons ◽  
Electromagnetic Wave Field ◽  
The Crab Nebula ◽  
The Continuum

The continuum emission from the Crab Nebula may be radiation from relativistic electrons moving in the electromagnetic wave field radiated by the rotating magnetic dipole of the pulsar. This radiation, called Synchro-Compton radiation, would show ordering over the whole nebula, as is observed in measurements of polarisation. The properties of this radiation are described in an Appendix.

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