scholarly journals The VSOP Survey: final aggregate results

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.

scholarly journals Brightness temperature for radio sources

2007 ◽  
Vol 3 (S245) ◽  
pp. 245-246
Author(s):  
J. H. Fan ◽  
Y. Huang ◽  
Y. Liu ◽  
Y. Gao ◽  
T. X. Hua ◽  
...  
Keyword(s):  
Brightness Temperature ◽  
Radio Astronomy ◽  
Radio Sources ◽  
University Of Michigan ◽  
Astronomy Observatory ◽  
Radio Astronomy Observatory ◽  
Brightness Temperatures ◽  
The University

AbstractIn this work, using the database of the university of Michigan Radio Astronomy Observatory (UMRAO), we determined the brightness temperatures, TB for a sample of 167 radio sources. The value of TB is in a range of log TB(K) = 10.46 to 20.08, which suggested that the boosting factors are in a range of δ = 0.41 to 41.26.

scholarly journals 5 GHz Polarization Observations of 33 Galactic Radio Sources

1975 ◽  
Vol 28 (2) ◽  
pp. 209 ◽  
Author(s):  
DK Milne ◽  
JR Dickel
Keyword(s):  
Supernova Remnants ◽  
Radio Sources ◽  
5 Ghz ◽  
Galactic Radio

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.

scholarly journals Surveys of Radio Sources at 5 GHz

1977 ◽  
Vol 74 ◽  
pp. 63-74
Author(s):  
I. I. K. Pauliny-Toth
Keyword(s):  
Flux Density ◽  
Radio Astronomy ◽  
Radio Sources ◽  
Astronomy Observatory ◽  
Max Planck ◽  
Radio Astronomy Observatory ◽  
Density Relation ◽  
Strong Source ◽  
Optical Identifications ◽  
5 Ghz

A number of surveys have been carried out at a frequency of 5 GHz at the National Radio Astronomy Observatory (NRAO) and at the Max-Planck-Institut für Radioastronomie (MPIfR), with the aim of determining the number-flux density relation for the sources detected and also of obtaining their radio spectra and optical identifications. The surveys fall into two categories: first, the strong source (S) surveys, which are intended in due course to cover the whole northern sky and to be complete above a flux density of about 0.6 Jy; second, surveys of limited areas of sky down to lower levels of the flux density.

scholarly journals Recent Very Bright Type IV Solar Metre-Wave Radio Emissions

1980 ◽  
Vol 91 ◽  
pp. 381-385 ◽  
Author(s):  
R. A. Duncan ◽  
R. T. Stewart ◽  
G. J. Nelson
Keyword(s):  
Radio Emission ◽  
Brightness Temperature ◽  
Radio Sources ◽  
Radio Emissions ◽  
Brightness Temperatures ◽  
Type Iv ◽  
Wave Radio

Stewart et al. (1978) have reported moving Type IV solar metre-wave radio outbursts with brightness temperatures between 108 and 1010 K. We now report Culgoora radioheliograph observations of four more Type IV radio sources, some moving, some stationary, but all with brightness temperatures above 109 K, and one with a brightness temperature above 1013 K. We also describe one of the previously reported events (that of 1977 September 20) in more detail. The interest of these events is that their high brightnesses place great strain upon the gyro-synchrotron theory of radio emission.

scholarly journals Combined-Array Imaging of Extra-Galactic Radio Sources

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.).

scholarly journals Interstellar Scattering And The Einstein Ring PKS 1830-211

1996 ◽  
Vol 173 ◽  
pp. 345-346
Author(s):  
D.L. Jones ◽  
R.A. Preston ◽  
D.W. Murphy ◽  
D.L. Meier ◽  
D.L. Jauncey ◽  
...  
Keyword(s):  
Brightness Temperature ◽  
Flux Density ◽  
Angular Size ◽  
Gravitational Lens ◽  
Radio Sources ◽  
Brightness Temperatures ◽  
Vlbi Observations ◽  
Data Support ◽  
Interstellar Scattering ◽  
Lower Frequencies

The remarkably strong radio gravitational lens PKS 1830-211 consists of a one arcsecond diameter Einstein ring with two bright compact components located on opposite sides of the ring. We have obtained 22 GHz VLBA data on this source to determine the intrinsic angular sizes of the compact components. Previous VLBI observations at lower frequencies indicate that the brightness temperatures of these components are significantly lower than 1010 K (Jauncey et al. 1991), less than is typical for compact synchrotron radio sources and less than is implied by flux density variations. A possible explanation is that interstellar scattering is broadening the apparent angular size of the source and thereby reducing the observed brightness temperature. Our VLBA data support this hypothesis.

scholarly journals 5-GHz VLBI Imaging Observations of 7 Equatorial AGNs

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.

Absorption in Radio Sources of High Brightness Temperature

Nature ◽  
1963 ◽  
Vol 200 (4901) ◽  
pp. 56-57 ◽  
Author(s):  
P. J. S. WILLIAMS
Keyword(s):  
Brightness Temperature ◽  
Radio Sources ◽  
High Brightness
Sign in / Sign up

Export Citation Format

Share Document