scholarly journals Measurements Of The Flux Density Of Discrete Radio Sources At 6 Cm Wavelength

1966 ◽  
Vol 19 (4) ◽  
pp. 577 ◽  
Keyword(s):  
Flux Density ◽  
Radio Telescope ◽  
Power Law ◽  
Radio Sources ◽  
Frequency Range ◽  
Thermal Radio ◽  
Discrete Radio Sources ◽  
Selection Of ◽  
Lower Frequencies

The flux densities of 67 non-thermal radio sources have been measured at a frequency of 5000 Mc/s with the CSIRO 210 ft radio telescope at Parkes. The sources were chosen from the stronger objects in the 3C catalogue (Edge et al. 1959), the CTA and CTD catalogues (Harris and Roberts 1960; Kellermann and Read 1965), and the Parkes catalogue (Bolton, Gardner, and Mackey 1964; Price and Milne 1965; Day et al. 1966). In the selection of sources observed in this program, special emphasis was placed on objects whose spectra at lower frequencies showed significant departures from the usual power law with an index near -0�8. Most of the sources reported here have not been previously measured at wavelengths shorter than 10 cm and thus the present observations extend the frequency range of their spectra by nearly a factor of two.

Observations of Shell-Type Galactic Radio Sources

1967 ◽  
Vol 1 (1) ◽  
pp. 21-21 ◽  
Author(s):  
E. R. Hill
Keyword(s):  
Radio Telescope ◽  
Shell Structure ◽  
Radio Spectrum ◽  
Radio Sources ◽  
Thermal Radio ◽  
Shell Type ◽  
Galactic Radio

Survey type observations have been made with the Parkes radio-telescope of 4 galactic radio sources having either a non-thermal radio spectrum, or exhibiting shell structure in their emitting regions. Observations were made at a wavelength of 11 cm using the Parkes radiotelescope where the beamwidth is about 7.5 min.arc.

The spectra of some discrete radio sources in 10?5000 MHz frequency range

1970 ◽  
Vol 8 (2) ◽  
pp. 275-322 ◽  
Author(s):  
S. Ya. Braude ◽  
A. V. Megn ◽  
B. P. Ryabov ◽  
I. N. Zhouck
Keyword(s):  
Radio Sources ◽  
Frequency Range ◽  
Discrete Radio Sources

scholarly journals Optical-faint compact radio sources

2017 ◽  
Author(s):  
◽  
Jacob Brown
Keyword(s):  
Optical Imaging ◽  
Flux Density ◽  
Power Law ◽  
Radio Sources ◽  
Exact Nature ◽  
Comprehensive Manner

This work investigates a population of bright, compact radio sources that are very faint in optical, which has never been studied before in a comprehensive manner. The sample consists of 135 radio sources selected from the Radio Fundamental Catalog (RFC). These sources have accurate VLBI positions, have ultra-compact radio morphologies (less than 10 mas), are strong in radio (median flux density [about]100 mJy), and yet are completely invisible in the SDSS DR10 data. While it is natural to guess that the OFCORS are powerful AGN, their exact nature is unclear. This multiwavelength study was performed by obtaining deeper optical imaging with OSMOS, CFHT, and PanSTARRS, perform SED fitting to determine the sources properties, explore the K-z andW1-z relations, and determine the power law in the infrared and radio regime.

scholarly journals 21. The low-frequency spectrum of Cygnus A and Cassiopeia A

1957 ◽  
Vol 4 ◽  
pp. 145-147
Author(s):  
R. J. Lamden ◽  
A. C. B. Lovell
Keyword(s):  
Lower Limit ◽  
Radio Telescope ◽  
Low Frequency ◽  
Radio Sources ◽  
Pencil Beam ◽  
Frequency Range ◽  
Present Communication ◽  
Cassiopeia A ◽  
Cygnus A ◽  
Radio Transmitters

The published measurements of the intensity of the radio sources cover a frequency range down to a lower limit of 22·6 Mc./s., at which measurements have been made on Cygnus and Cassiopeia by Hey and Hughes (1954)[1]. Information about the spectrum at still lower frequencies is difficult to obtain because of interference arising from ionospheric reflexion of distant radio transmitters. Some of this trouble can be alleviated by using a narrow pencil-beam radio telescope for reception and the present communication describes measurements made on frequencies of 16·5, 19·0, 22·6 and 30·0 Mc./s. using the 218 ft. transit radio telescope at Jodrell Bank.

scholarly journals Gain Measurements of Large Aerials Used in Interferometer and Cross?Type Radio Telescopes

1958 ◽  
Vol 11 (1) ◽  
pp. 70 ◽  
Author(s):  
AG Little
Keyword(s):  
Radio Telescope ◽  
Radio Sources ◽  
Radio Telescopes ◽  
Discrete Radio Sources ◽  
Cross Type

A method has been developed for measuring the gain of large interferometer and cross-type radio telescope aerials. Use is made of the strong discrete radio sources, whose intensity need not be known, to allow comparison of the gains of the aerials with that of a standard.

scholarly journals Intraday Variability in Northern Hemisphere Radio Sources

2002 ◽  
Vol 19 (1) ◽  
pp. 14-18 ◽  
Author(s):  
T. P. Krichbaum ◽  
A. Kraus ◽  
L. Fuhrmann ◽  
G. Cimò ◽  
A. Witzel
Keyword(s):  
Flux Density ◽  
Radio Telescope ◽  
Physical Interpretation ◽  
Radio Sources ◽  
Intrinsic Variability ◽  
The Past ◽  
Interstellar Scintillation ◽  
Variability Pattern ◽  
Complex Source ◽  
Intraday Variability

AbstractWe summarise results from flux density monitoring campaigns performed with the 100 m radio telescope at Effelsberg and the VLA during the past 15 yrs. We briefly discuss some of the statistical properties from now more than 40 high declination sources (δ ≥ 30°), which show intraday variability (IDV). In general, IDV is more pronounced for sources with flat radio spectra and compact VLBI structures. For 0917+62, we present new VLBI images which suggest that the variability pattern is modified by the occurrence of new jet components. For 0716+71, we show the first detection of IDV at millimetre wavelengths (32 GHz). For the physical interpretation of the IDV phenomenon, a complex source and frequency dependent superposition of interstellar scintillation and source intrinsic variability should be considered.

scholarly journals Compact Jets in 100 AGNs with the Strongest Broad-Band Variability of 1-22 GHz Spectra in 1997-2001

2002 ◽  
Vol 184 ◽  
pp. 297-298
Author(s):  
Yu. A. Kovalev ◽  
Y. Y. Kovalev ◽  
N. A. Nizhelsky ◽  
A. V. Bogdantsov
Keyword(s):  
Magnetic Field ◽  
Physical Model ◽  
Flux Density ◽  
Radio Telescope ◽  
Longitudinal Magnetic Field ◽  
Broad Band ◽  
Radio Sources ◽  
Spectral Evolution ◽  
Model Interpretation ◽  
Relativistic Jet

AbstractResults of monitoring observations at the radio telescope RATAN-600 and a model interpretation of instantaneous 1-22 GHz spectra at six frequencies for 100 selected AGNs are presented. The index of variability at these frequencies is shown for 550 sources monitored in 1997-2001 at 11 epochs. The spectra of the selected sources exhibit flux density variations of about 50% and up. The type of spectral evolution is similar for all the selected objects, favoring the same basic physical model. Model analysis shows that the nature of the radio sources and the observed variability behavior of the spectra can be explained by a model with a relativistic jet of parsec scale in a longitudinal magnetic field.

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