scholarly journals Australian Journal of Physics Astrophysical Supplements

1973 ◽  
Vol 26 (5) ◽  
pp. 689
Author(s):  
M Davies ◽  
AG Little ◽  
BY Mills
Keyword(s):  
Flux Density ◽  
Australian Journal ◽  
Radio Sources

A catalogue of radio sources observed at a frequency of 408 MHz with the Molonglo radiotelescope is presented. The catalogue includes an area of 0�21 sr between declinations -19�.3 and - 22� �4. A total of 1545 sources is listed down to a limiting flux density of O� 1 f.u., the catalogue being largely complete above 0�25 f.u. Errors in position vary from ~ 5N arc for sources stronger than 1 f.u. to ~ 30N arc for the weakest sources.

scholarly journals Australian Journal of Physics Astrophysical Supplement

1976 ◽  
Vol 29 (5) ◽  
pp. 471
Author(s):  
JN Clarke ◽  
AG Little ◽  
BY Mills
Keyword(s):  
Flux Density ◽  
High Frequency ◽  
Magellanic Clouds ◽  
Australian Journal ◽  
The Other ◽  
Optical Data ◽  
Radio Sources ◽  
Angular Extent

The fourth catalogue of radio sources observed at 408 MHz with the Molonglo radiotelescope is presented. A total of 1349 sources is listed to a limiting flux density of 0�2 Jy, the catalogue being largely complete above 0� 25 Jy. The area of sky surveyed includes the Magellanic Clouds as well as a comparison region of similar angular extent. Detailed notes are provided on some of the Cloud sources, and maps are given for complex sources in the region of the Clouds. Those sources for which high-frequency or optical data are available are classified into two lists, one of Cloud members and the other of 'unidentified nonthermal sources', presumably not Cloud members.

scholarly journals Australian Journal of Physics Astrophysical Supplement

1975 ◽  
Vol 28 (6) ◽  
pp. 755
Author(s):  
Beverley J Wills
Keyword(s):  
Flux Density ◽  
Australian Journal ◽  
Radio Sources

Accurate measurements of relative flux density have been made between frequencies of 468 and 5009 MHz for 300 radio sources selected from the Parkes catalogue. The observations, their analysis and accuracy are described, and the flux densities presented together with their errors. Excluding the uncertainties in scaling these flux densities to an absolute system, r.m.s. errors vary from 0�24 Jy and 2�4 % at 635 MHz to 1�8 % at 2700 MHz; uncertainties in 'absolute' scaling are thought to be about 5 %. The present flux densities are compared with accurate values published elsewhere. The data have been combined with other published flux densities between 10 and 10000 MHz to derive spectra, which are presented graphically. Some sources whose spectra may be useful for flux density calibration are noted.

scholarly journals Australian Journal of Physics Astrophysical Supplement

1973 ◽  
Vol 26 (1) ◽  
pp. 115
Author(s):  
OB Slee ◽  
CS Higgins
Keyword(s):  
Radio Source ◽  
Flux Density ◽  
Australian Journal ◽  
Radio Sources ◽  
Success Rates ◽  
Low Resolution ◽  
Upper Limits

The Culgoora radioheliograph operating at 80 MHz has been used to observe 999 radio sources selected from published catalogues and distributed over the declination range -48� to +35�. The Culgoora-l list contains measurements with 3' . 7 arc resolution of positions, flux densities, and angular sizes of 777 sources, while upper limits to the flux densities of 222 undetected sources are given in a separate list. Success rates for the detection of various classes of radio source at 80 MHz are listed and discussed. Comparisons are made between the Culgoora flux densities and those given in other catalogues, and it is shown that unresolved sources in the earlier low-resolution measurements near 80 MHz cause the flux density to be systematically overestimated.

scholarly journals Australian Journal of Physics Astrophysical Supplement

1975 ◽  
Vol 28 (2) ◽  
pp. 239
Author(s):  
JG Bolton ◽  
AJ Shimmins ◽  
JV Wall
Keyword(s):  
Flux Density ◽  
Galactic Plane ◽  
Australian Journal ◽  
Radio Sources

A catalogue of 34S radio sources is presented, covering right ascensions O&h 00'" to 17hOO'" and 19h30'" to 06h30'" between declinations _4� and -30�. The regions omitted re within - 10� of the galactic plane. The catalogue was compiled from a 'fast' finding survey at 2700 MHz aimed at detecting sources stronger than o� 5 Jy. Subsequent measurements of flux density and position were made on all the sources which were not in the Parkes 40S MHz catalogue, and on some sources in the Parkes 40S MHz catalogue for which only data of low accuracy were available.

scholarly journals Flux density measurements of variable radio sources at   8.96 mm (33.5 GHz)

1981 ◽  
Vol 194 (4) ◽  
pp. 961-966 ◽  
Author(s):  
A. M. Flett ◽  
C. Henderson
Keyword(s):  
Flux Density ◽  
Radio Sources ◽  
Density Measurements ◽  
Variable Radio

scholarly journals VLBA+GBT observations of the COSMOS field and radio source counts at 1.4 GHz

2018 ◽  
Vol 616 ◽  
pp. A128 ◽  
Author(s):  
N. Herrera Ruiz ◽  
E. Middelberg ◽  
A. Deller ◽  
V. Smolčić ◽  
R. P. Norris ◽  
...  
Keyword(s):  
Radio Source ◽  
Flux Density ◽  
Lower Limit ◽  
High Sensitivity ◽  
Host Galaxy ◽  
Radio Sources ◽  
Source Population ◽  
Star Forming ◽  
Brightness Temperatures ◽  
Long Baseline

We present very long baseline interferometry (VLBI) observations of 179 radio sources in the COSMOS field with extremely high sensitivity using the Green Bank Telescope (GBT) together with the Very Long Baseline Array (VLBA) (VLBA+GBT) at 1.4 GHz, to explore the faint radio population in the flux density regime of tens of μJy. Here, the identification of active galactic nuclei (AGN) is based on the VLBI detection of the source, meaning that it is independent of X-ray or infrared properties. The milli-arcsecond resolution provided by the VLBI technique implies that the detected sources must be compact and have large brightness temperatures, and therefore they are most likely AGN (when the host galaxy is located at z ≥ 0.1). On the other hand, this technique only allows us to positively identify when a radio-active AGN is present, in other words, we cannot affirm that there is no AGN when the source is not detected. For this reason, the number of identified AGN using VLBI should be always treated as a lower limit. We present a catalogue containing the 35 radio sources detected with the VLBA+GBT, ten of which were not previously detected using only the VLBA. We have constructed the radio source counts at 1.4 GHz using the samples of the VLBA and VLBA+GBT detected sources of the COSMOS field to determine a lower limit for the AGN contribution to the faint radio source population. We found an AGN contribution of >40−75% at flux density levels between 150 μJy and 1 mJy. This flux density range is characterised by the upturn of the Euclidean-normalised radio source counts, which implies a contribution of a new population. This result supports the idea that the sub-mJy radio population is composed of a significant fraction of radio-emitting AGN, rather than solely by star-forming galaxies, in agreement with previous studies.

Variable Radio Sources at 843 MHz

1994 ◽  
Vol 11 (1) ◽  
pp. 33-38 ◽  
Author(s):  
D. Campbell-Wilson ◽  
R. W. Hunstead
Keyword(s):  
Interstellar Medium ◽  
Flux Density ◽  
Large Amplitude ◽  
Preliminary Report ◽  
Radio Sources ◽  
Amplitude Variability ◽  
Variable Radio

AbstractThis paper is a preliminary report on the flux density monitoring of calibration sources used at the Molonglo Observatory Synthesis Telescope. We show two examples of large amplitude variability at 843 MHz which we attribute to refractive scintillation in the Galactic interstellar medium.

scholarly journals A Catalogue of Galactic Radio Sources

1968 ◽  
Vol 21 (3) ◽  
pp. 369 ◽  
Author(s):  
MJL Kesteven
Keyword(s):  
Flux Density ◽  
Spectral Index ◽  
Galactic Plane ◽  
Radio Sources ◽  
Galactic Radio

The results of a survey of radio sources in the galactic plane in the longitude range 1800 to 400 with the 1 mile Molonglo Cross telescope at 408 MHz are presented. The methods of observation and reduction are described briefly. The catalogue lists the position, flux density, size, and spectral index for 80 sources

The Over-estimation of the Flux Density of Weak Radio Sources

1969 ◽  
Vol 1 (5) ◽  
pp. 233-234
Author(s):  
H. S. Murdoch
Keyword(s):  
Monte Carlo ◽  
Flux Density ◽  
Lower Limit ◽  
Error Distribution ◽  
Radio Sources ◽  
Systematic Bias ◽  
Digital Recording ◽  
Analysis Techniques ◽  
Monte Carlo Techniques ◽  
The Past

The over-estimation of the flux density of radio sources near the lower limit of a survey has often been considered in the past. The use of digital recording and analysis techniques now enables a quantitative approach to the problem. Monte Carlo techniques may be used to determine the error distribution, including any systematic bias.

Four Southern Intraday Variable Radio Sources

1998 ◽  
Vol 164 ◽  
pp. 271-272 ◽  
Author(s):  
L. L. Kedziora-Chudczer ◽  
D. L. Jauncey ◽  
M. H. Wieringa ◽  
J. E. Reynolds ◽  
A. K. Tzioumis
Keyword(s):  
Flux Density ◽  
Progress Report ◽  
Radio Sources ◽  
High Flux ◽  
Inverted Spectrum ◽  
Spectrum Radio ◽  
Variable Radio

AbstractThis is a progress report on the ATCA IDV survey of compact, flat or inverted spectrum radio sources. We found that four sources: PKS 0405–385, PKS 1034–293, PKS 1144–397, and PKS 1519–273 out of the sample of 125 show high flux density variability on the daily timescale. The characteristics of observed IDV are discussed and we reflect on its possible origin.

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