Maps of Six Extra-Galactic Radio Sources at 5 GHz

Polarization observations have been made of 33 galactic radio sources, mostly supernova remnants, at a frequency of 5 GHz using the 64 m telescope at Parkes. Maps of the observed polarization vectors superposed upon total intensity isotherms are presented for each source.

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The VSOP Survey: final aggregate results

Proceedings of the International Astronomical Union ◽

10.1017/s1743921307005431 ◽

2006 ◽

Vol 2 (S238) ◽

pp. 357-358

Author(s):

R. Dodson ◽

S. Horiuchi ◽

W. Scott ◽

E. Fomalont ◽

Z. Paragi ◽

...

Keyword(s):

Brightness Temperature ◽

Radio Astronomy ◽

Radio Sources ◽

Survey Paper ◽

Brightness Temperatures ◽

Future Space ◽

Magnetic Spectrum ◽

Electro Magnetic ◽

5 Ghz ◽

Galactic Radio

AbstractIn February 1997 the Japanese radio astronomy satellite HALCA was launched to provide the space-borne element for the VSOP mission. HALCA provided linear baselines three-times greater than that of ground arrays, thus providing higher resolution and higher AGN brightness temperature measurements and limits. Twenty-five percent of the scientific time of the mission was devoted to the “VSOP survey” of bright, compact, extra-galactic radio sources at 5 GHz. A complete list of 294 survey targets were selected from pre-launch surveys, 91% of which were observed during the satellite's lifetime.The major goals of the VSOP Survey are statistical in nature: to determine the brightness temperature and approximate structure, to provide a source list for use with future space VLBI missions, and to compare radio properties with other data throughout the electro-magnetic spectrum. All the data collected have now been analysed and is being prepared for the final image Survey paper. In this paper we present details of the mission, and some statistics of the images and brightness temperatures.

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Combined-Array Imaging of Extra-Galactic Radio Sources

International Astronomical Union Colloquium ◽

10.1017/s0252921100019278 ◽

1994 ◽

Vol 140 ◽

pp. 123-124

Author(s):

Chidi E. Akujor ◽

Lars B. Bååth

Keyword(s):

Structural Information ◽

Small Scale ◽

Radio Sources ◽

Single Image ◽

Yield Information ◽

5 Ghz ◽

Array Imaging ◽

The Relationship ◽

Telescope Arrays ◽

Galactic Radio

The resolving powers of existing telescope arrays are quite different. For example the extended new MERLIN at 5 GHz readily yields maps of ~ 50 mas resolution compared with the VLA ~ 350 mas, WSRT ~ 4000 mas, EVN ~ 5 mas, global VLBI ~ 1 mas, etc. This means that images obtained with these instruments yield information on different scales that sometimes appear unrelated. However, the need to have structural information on intermediate scales demands that data from different arrays be combined to make a single image. This is particularly important in extra-galactic radio sources where the relationship between core-jet features on different scales (parsec and kiloparsec) and the connection between small-scale and extended features need to be established.By combining uvdata from two or more arrays we can routinely make images that represent a balance between the capabilities of the combined arrays, (e.g. VLA + MERLIN, MERLIN+VLBI, VLA+WSRT etc) at cm wavelengths. In order to do this, one has to overcome a number of calibration and mapping difficulties (see Zhang et al. 1991; Akujor et al. 1992, in prep.).

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5-GHz VLBI Imaging Observations of 7 Equatorial AGNs

International Astronomical Union Colloquium ◽

10.1017/s0252921100030918 ◽

2002 ◽

Vol 184 ◽

pp. 304-305

Author(s):

Z.-Q. Shen ◽

D. R. Jiang ◽

Y.J. Chen ◽

T.-S. Wan

Keyword(s):

Radio Sources ◽

Preliminary Results ◽

The Third ◽

5 Ghz

AbstractSince 1992 we have been conducting a 5-GHz VLBI imaging survey of southern and equatorial radio sources. So far, we have published the results of two observing sessions with 26 southern radio sources imaged in total (Shen et al. 1997; 1998). In this paper, we present the preliminary results of the third session of observations of 7 equatorial sources in the sample.

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The follow-up European VLBI Network observations of twelve GPS radio sources at 5 GHz

Astronomy and Astrophysics ◽

10.1051/0004-6361/201014075 ◽

2010 ◽

Vol 518 ◽

pp. A23 ◽

Cited By ~ 2

Author(s):

L. Cui ◽

X. Liu ◽

J. Liu ◽

H.-G. Song ◽

Z. Ding

Keyword(s):

Radio Sources ◽

5 Ghz

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A Catalogue of Galactic Radio Sources

Australian Journal of Physics ◽

10.1071/ph680369 ◽

1968 ◽

Vol 21 (3) ◽

pp. 369 ◽

Cited By ~ 31

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

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A Novel Method for Estimating the Ambient Medium Density Around Distant Radio Sources from Their Observed Radio Spectra

The Astrophysical Journal ◽

10.3847/1538-4357/ac116c ◽

2021 ◽

Vol 922 (2) ◽

pp. 197

Author(s):

Anna Wójtowicz ◽

Łukasz Stawarz ◽

Jerzy Machalski ◽

Luisa Ostorero

Keyword(s):

Radio Emission ◽

Ambient Medium ◽

Radio Galaxies ◽

Radiative Properties ◽

Radio Continuum ◽

Physical Parameters ◽

Radio Sources ◽

Data Set ◽

Radio Structure ◽

5 Ghz

Abstract The dynamical evolution and radiative properties of luminous radio galaxies and quasars of the FR II type, are well understood. As a result, through the use of detailed modeling of the observed radio emission of such sources, one can estimate various physical parameters of the systems, including the density of the ambient medium into which the radio structure evolves. This, however, requires rather comprehensive observational information, i.e., sampling the broadband radio continua of the targets at several frequencies, and imaging their radio structures with high resolution. Such observations are, on the other hand, not always available, especially for high-redshift objects. Here, we analyze the best-fit values of the source physical parameters, derived from extensive modeling of the largest currently available sample of FR II radio sources, for which good-quality multiwavelength radio flux measurements could be collected. In the analyzed data set, we notice a significant and nonobvious correlation between the spectral index of the nonthermal radio emission continuum, and density of the ambient medium. We derive the corresponding correlation parameters, and quantify the intrinsic scatter by means of Bayesian analysis. We propose that the discovered correlation could be used as a cosmological tool to estimate the density of ambient medium for large samples of distant radio galaxies. Our method does not require any detailed modeling of individual sources, and relies on limited observational information, namely, the slope of the radio continuum between the rest-frame frequencies 0.4 and 5 GHz, possibly combined with the total linear size of the radio structure.

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Some Observations of Shell-type Galactic Radio Sources

Australian Journal of Physics ◽

10.1071/ph670297 ◽

1967 ◽

Vol 20 (3) ◽

pp. 297 ◽

Cited By ~ 12

Author(s):

ER Hill

Keyword(s):

Radio Emission ◽

Spherical Symmetry ◽

Supernova Remnants ◽

Supernova Remnant ◽

Milky Way ◽

Radio Sources ◽

Radio Observations ◽

Shell Type ◽

Rosette Nebula ◽

Galactic Radio

Radio evidence for two new supernova remnants in the Southern Milky Way is presented. Some new observations of the known supernova remnant, source 1439-62, and of the Rosette nebula, a shell source but not a supernova remnant, are also presented. The problem of finding model shells to fit the radio observations is considered and it is shown that the radio emission from 1439-62 is unlikely to originate in a shell with spherical symmetry.

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VLBI Survey of a Complete Sample of Active Nuclei and Quasars

Symposium - International Astronomical Union ◽

10.1017/s007418090007755x ◽

1984 ◽

Vol 110 ◽

pp. 15-24 ◽

Cited By ~ 2

Author(s):

T. J. Pearson ◽

A.C.S. Readhead

Keyword(s):

Flux Density ◽

Radio Sources ◽

Complete Sample ◽

Limited Sample ◽

Extragalactic Radio Sources ◽

5 Ghz ◽

Number Of Classes ◽

Compact Sources ◽

Continuous Range

We have conducted a VLBI survey of a complete, flux-density limited sample of 65 extragalactic radio sources, selected at 5 GHz. We have made hybrid maps at 5 GHz of all of the sources accessible to the Mark-II system. The sources can be divided provisionally into a number of classes with different properties: central components of extended double sources, steep-spectrum compact sources, very compact (almost unresolved) sources, asymmetric sources (sometimes called “core-jet” sources), and “compact double” sources. It is not yet clear whether any of these classes is physically distinct from the others, or whether there is a continuous range of properties.

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Variable Radio Sources

Symposium - International Astronomical Union ◽

10.1017/s0074180900028023 ◽

1982 ◽

Vol 97 ◽

pp. 317-324 ◽

Cited By ~ 2

Author(s):

R. Fanti ◽

L. Padrielli ◽

M. Salvati

Keyword(s):

Energy Supply ◽

Theoretical Models ◽

Accelerated Expansion ◽

Radio Sources ◽

Relativistic Electrons ◽

Plasma Cloud ◽

Basic Process ◽

Continuous Energy ◽

Galactic Radio ◽

Variable Radio

Flux variations are a common feature of flat spectrum compact extra-galactic radio sources. Detailed analysis and quantitative comparisons with theoretical models (e.g. van der Laan, 1966) are difficult due to the complex characteristics of the flux variations, which generally appear to consist of different outbursts blended together in time. Nevertheless, the general consensus is that the basic process has been correctly identified and consists in an expansion of a synchrotron radiating plasma cloud of relativistic electrons and magnetic field partially opaque to its own radiation. The main differences between data and predictions of the theory are that the variations propagate too fast and with too large amplitude toward lower frequencies. This behaviour however may be indicative of continuous energy supply and consequent accelerated expansion.

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