On a possible mechanism responsible for the differential energy spectrum of relativistic electrons and non-linear low-frequency spectra of cosmic radio sources

1973 ◽  
Vol 20 (1) ◽  
pp. 59-70 ◽  
Author(s):  
S. Ya. Braude ◽  
�. A. Kaner
Keyword(s):  
Energy Spectrum ◽  
Low Frequency ◽  
Radio Sources ◽  
Cosmic Radio ◽  
Relativistic Electrons ◽  
Frequency Spectra ◽  
Differential Energy Spectrum ◽  
Non Linear

scholarly journals ENVIRONMENT DENSITY OF A GIANT RADIO STRUCTURE FOR GALAXIES AND QUASARS WITH STEEP RADIO SPECTRA

2021 ◽  
Vol 26 (2) ◽  
pp. 165-172
Author(s):  
A. P. Miroshnichenko ◽  
Keyword(s):  
Low Frequency ◽  
Radio Spectrum ◽  
Power Relation ◽  
Cosmological Evolution ◽  
Inverse Power ◽  
Radio Sources ◽  
Frequency Spectra ◽  
Radio Structure ◽  
Mean Values ◽  
Index Value

Purpose: Estimate of the environment density of giant (with the linear size of about megaparsec) radio structures for galaxies and quasars with steep low-frequency spectra taken from the UTR-2 catalogue. Study of the cosmological evolution of environment density of giant radio sources. Determination of dependence of contribution of radio lobes into the emission of giant sources with respect to their environment density. Design/methodology/approach: We use the sample of sources from the UTR-2 catalogue of extragalactic sources to estimate the environment density for giant sources with steep low-frequency spectra. The selection criteria for the examined objects are the following: 1) the spectral index value is equal or larger than 1; 2) the fl ux density of emission at the frequency of 25 MHz is larger than 10 Jy; 3) the sample sources are optically identifi ed. The value of environment density of examined sources is obtained with the assumption of equality of source jet luminosity (at the synchrotron mechanism of radio emission) and its corresponding kinetic luminosity. The analysis of the estimates of environment densities is made for different classes of the sample objects (for galaxies and quasars with linear steep spectra and with break steep spectra). Findings: The estimates of environment density have been derived for giant radio structures formed by the jets of sources with steep spectrum from the UTR-2 catalogue. On the average, the environment density for the quasar structure (~ 10-28 g/sm3) is lesser than the one for the galaxies (~ 10-27 g/sm3 to ~ 10-26 g/sm3). The larger jet environment density is typical for the galaxies and quasars with the break steep spectra than for those with the linear steep spectra. The inverse power relation of the jet environment density and the source redshift (the cosmological evolution of the jet environment density) has been derived. The contribution of jet-related radio lobes into the emission of sources displays the inverse power relation for the environment density of the corresponding radio structures. Conclusions: The mean values of obtained estimates of environment density of giant jets of radio sources with steep low-frequency spectra indicate the lesser environment density of quasar jets than that for the galaxy jets. Giant radio sources with steep low-frequency spectrum (especially, with break steep spectrum) reveal considerable evolution of environment density of jets. The larger contribution of radio lobes (jets) into the emission of sources corresponds to the lesser environment density of sources taken from the UTR-2 catalogue. It can be due to propagation of jets (surrounded by radio lobes) from powerful radio sources to distances of about megaparsec, until the balance of source’s environment density and extragalactic environment density is reached. Key words: steep low-frequency radio spectrum; giant radio structure; jets; radio lobes; galaxies; quasars; environment density

scholarly journals Intensity Variations in Extragalactic Radio Sources at 13 cm

1972 ◽  
Vol 44 ◽  
pp. 224-224 ◽  
Author(s):  
G. D. Nicolson
Keyword(s):  
Low Frequency ◽  
Secular Change ◽  
Radio Sources ◽  
Complete Sample ◽  
Frequency Spectra ◽  
Extragalactic Radio Sources ◽  
The Relationship

Results of a three-year investigation into the variability of 55 Parkes sources at 13 cm are presented. Thirty-six of the sources comprise a complete sample of QSS with fluxes exceeding 2 flux units. The remaining sources include most other known or likely variables stronger than 2 flux units. The relationship between spectra and variability in QSS is investigated and it is confirmed that variables generally have flat low frequency spectra. A possible relationship between redshift and specific types of intensity variations is considered. Limits on the secular change in the intensity of non-variable QSS are set and are generally found to be ± 1.5% p.a. at 13 cm. Results for the remaining 19 sources are discussed and some preliminary findings of an extension patrol to include weaker sources in the range 1-2 flux units are given.

Low-frequency spectra of extragalactic radio sources

Astrophysics ◽  
1970 ◽  
Vol 4 (4) ◽  
pp. 252-255
Author(s):  
A. M. Aslanyan ◽  
V. G. Malumyan ◽  
V. A. Sanamyan
Keyword(s):  
Low Frequency ◽  
Radio Sources ◽  
Frequency Spectra ◽  
Extragalactic Radio Sources

scholarly journals Independent estimates of energies of steep-spectrum radio sources

2013 ◽  
Vol 9 (S304) ◽  
pp. 96-99
Author(s):  
Alla Miroshnichenko
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Low Frequency ◽  
Relativistic Electrons ◽  
Frequency Spectra ◽  
Inverse Compton Scattering ◽  
Spectrum Radio ◽  
The Magnetic Field ◽  
Relativistic Particles

AbstractWe examine properties of galaxies and quasars with steep low-frequency spectra from the UTR-2 catalogue. The number of the objects have the non-thermal X-ray emission due to the inverse Compton scattering of radio photons of the microwave background by relativistic electrons. So, it is possible to estimate the magnetic field strength and the ratio of energies of the magnetic field and relativistic particles, independently. As we have received the determined values of magnetic field strength are near to one order less than those at the well-known energy equipartition condition. We conclude from the obtained energy ratio that the energy of relativistic particles prevails over the energy of magnetic field in the galaxies and quasars with steep radio spectra.

The low-frequency spectra of a complete sample of extragalactic radio sources

1984 ◽  
Vol 89 ◽  
pp. 323 ◽  
Author(s):  
L. Gregorini ◽  
F. Mantovani ◽  
A. Eckart ◽  
P. Biermann ◽  
A. Witzel ◽  
...  
Keyword(s):  
Low Frequency ◽  
Radio Sources ◽  
Complete Sample ◽  
Frequency Spectra ◽  
Extragalactic Radio Sources

Generation of surf beat by non-linear wave interactions

1971 ◽  
Vol 49 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Brent Gallagher
Keyword(s):  
Gravity Waves ◽  
Numerical Evaluation ◽  
Low Frequency ◽  
Linear Wave ◽  
Transfer Energy ◽  
Wave Interactions ◽  
Frequency Spectra ◽  
Non Linear ◽  
Linear Interactions ◽  
Low Frequency Waves

Non-linear interactions among wind-generated gravity waves transfer energy to low frequency waves in a coastal zone. A transfer function is derived for a straight coastline of constant bottom slope. This model is applied to three actual cases, and numerical evaluation of the energy transfer produces low frequency spectra which are compared with observations.

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