Flux Densities at 8·87 GHz of 347 Small-diameter Radio Sources

1981 ◽  
Vol 34 (4) ◽  
pp. 471 ◽  
Author(s):  
AJ Shimmins ◽  
JG Bolton
Keyword(s):  
Flux Density ◽  
Integration Method ◽  
Small Diameter ◽  
Radio Sources ◽  
Density Scale

Flux densities at" 8�87 GHz (A = 3�4 cm) have been determined with the Parkes 64 m telescope for 347 radio sources, using an improved on-off integration method. The sources were selected from the Parkes 2700 MHz catalogue as those having estimated flux densities at 8�87 GHz greater than 0'5 Jy (= 0�5 x 1O- 26 Wm-2 Hz-I) and relatively small angular sizes. A total of 156 of the sources are identified with QSOs and 58 with galaxies, and 133 have not been optically identified. Of the 347 sources 101 have been previously measured at this frequency at Parkes. Some of these repeats were made to check variability and others to compare the flux density scale with that of previous measurements. The estimated accuracy of most of the measurements is � 0�034 Jy (r.m.s.) due to noise and confusion and 3�0 % due to other causes.

scholarly journals 8·8 GHz Radio Observations of 12 Suggested Supernova Remnants

1973 ◽  
Vol 26 (3) ◽  
pp. 379 ◽  
Author(s):  
JR Dickel ◽  
DK Milne ◽  
AR Kerr ◽  
JG Ables
Keyword(s):  
Flux Density ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Galactic Plane ◽  
Small Diameter ◽  
Radio Sources ◽  
Radio Observations ◽  
Frequency Measurements ◽  
Thermal Spectrum

Brightness distributions and flux densities at 8�8 GHz are presented for 12 small-diameter radio sources near the galactic plane. Each of these sources has been classified at one time or another as a supernova remnant. For one source, G295� 2 - 0�6, the flux density at 8�8 GHz confirms the thermal spectrum suggested by lower frequency measurements and indicates that it is not a supernova remnant. Another source, G309� 6+ 1�7, is thought to be extragalactic.

scholarly journals 5000 MHz Flux Densities and Spectra for 325 Small-diameter Radio Sources at Low Galactic Latitudes

1975 ◽  
Vol 28 (5) ◽  
pp. 633 ◽  
Author(s):  
JL Caswell ◽  
RF Haynes ◽  
DH Clark
Keyword(s):  
Flux Density ◽  
Small Diameter ◽  
Radio Sources ◽  
Density Measurements

Flux density measurements at 5000 MHz are presented for 325 of the small-diameter sources detected in the Molonglo 408 MHz galactic survey. By investigating the spectra we show that probably between 10 % and 15 % of the sources are galactic and the remainder extragalactic.

scholarly journals Intensity Distribution of Interplanetary Scintillation at 408 MHz

1975 ◽  
Vol 28 (5) ◽  
pp. 621 ◽  
Author(s):  
RG Milne
Keyword(s):  
Flux Density ◽  
Intensity Distribution ◽  
Small Diameter ◽  
Point Sources ◽  
Radio Sources ◽  
Interplanetary Scintillation ◽  
The Core ◽  
Intensity Fluctuations

It is shown that interplanetary scintillation of small-diameter radio sources at 408 MHz produces intensity fluctuations which are well fitted by a Rice-squared. distribution, better so than is usually claimed. The observed distribution can be used to estimate the proportion of flux density in the core of 'core-halo' sources without the need for calibration against known point sources.

scholarly journals Accurate Flux Densities at 8·87 GHz of 195 Radio Sources

1973 ◽  
Vol 26 (1) ◽  
pp. 93 ◽  
Author(s):  
AJ Shimmins ◽  
JV Wall
Keyword(s):  
Flux Density ◽  
Integration Method ◽  
Radio Sources ◽  
Hii Region ◽  
System Noise

Accurate flux densities at 8�87 GHz have been determined with the Parkes 64 m telescope for 195 radio sources, using an on-off integration method. The sources were selected from the Parkes 408 and 2700 MHz catalogues as those having estimated flux densities at 8�87 GHz greater than O' 5 f.u. and relatively small angular sizes. Eighty of the selected sources are identified with QSO's, 40 with galaxies, and one with an HII region, while 74 have not been identified. The estimated accuracy of the flux density is �0�02 f.u. (r.m.s.) due to system noise and �3'5% due to other causes. A list of known or newly suspected radio variables in the sample is given.

scholarly journals A Catalogue of Small-diameter Radio Sources Close to the Galactic Plane

1974 ◽  
Vol 27 (5) ◽  
pp. 713 ◽  
Author(s):  
DH Clark ◽  
DF Crawford
Keyword(s):  
Flux Density ◽  
Galactic Plane ◽  
Small Diameter ◽  
Hii Regions ◽  
Radio Sources ◽  
Galactic Radio

A catalogue of 'smaIl-diameter' galactic radio sources observed at a frequency of 408 MHz with the Molonglo radiotelescope is presented. The catalogue covers an area of 0�40 sr enclosed in the range [II = 190�-360�-50�, 1 bIll..;; 3�. The sources listed are those which show no significant broadening of the ~ 3' arc aerial beam. Small-diameter features bounded or confused by extended regions of emission are not included. A total of 513 sources are listed above a flux density of O' 6 Jy. While most of these are expected to be extragalactic, the list includes some known pulsars and small-diameter HII regions. The catalogue should form a useful search list for the identification of other such galactic objects.

scholarly journals An All-sky Catalogue of Strong Radio Sources at 408 MHz

1973 ◽  
Vol 26 (3) ◽  
pp. 403 ◽  
Author(s):  
JG Robertson
Keyword(s):  
Flux Density ◽  
Galactic Plane ◽  
Magellanic Cloud ◽  
Radio Sources ◽  
Extragalactic Radio Sources ◽  
Density Scale

A catalogue of 160 extragalactic radio sources stronger than 10 f.u. at 408 MHz has been compiled by selecting sources from the Parkes and 3CR surveys but adopting the most accurate values of flux density that are available. The sky coverage of 10�1 sr omits only the galactic plane and Magellanic Cloud regions. The flux density scale due to Wyllie has been used throughout.

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.

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