NRAO 5GHz Strong Source Survey Virtual Observatory Resource

Authors
  1. Pauliny-Toth I.I.K.
  2. Kellermann K.I.
  3. Published by
    CDS
Abstract

The 140-ft telescope at the National Radio Astronomy Observatory has been used to extend the 5-GHz strong source (S) survey over an area of 1.14 steradian. Some 240 sources have been detected in this region, of which 135 are above the completeness limit of 0.6f.u. The distribution of spectral indices for sources above the completeness limit is much broader than for samples selected from long-wavelength surveys, owing to an increase in the fraction of compact sources with flat spectra. For about half of the sources selected at 6 cm, the spectral index {alpha}>-0.5. Analysis of the dependence of the spectral index on the flux density shows that, as expected from the 408-MHz number counts and spectral index distribution, at 5 GHz there are fewer flat spectra among the weak sources than among the stronger ones. The spectral index distributions for the identified galaxies and quasars show the familiar forms: the galaxies have a strong concentration near {alpha}=-0.8 with a small tail extending toward flat spectra. The quasars show a much broader distribution of indices, but the fraction (80%) of quasars having flat spectra ({alpha}>-0.5) is much greater than that found in the low-frequency surveys. The number-flux density relation for various groups of sources selected from the 5-GHz survey show that the anomalously steep slope is confined to (a) unidentified sources, (b) sources with steep spectra ({alpha}<-0.5), and (c) sources located in the north galactic hemisphere. Sources identified with radio galaxies or quasars, or which have flat spectra, or which are in the south galactic hemisphere all show a number-flux density slope near -1.5.

Keywords
  1. radio-sources
  2. surveys
Bibliographic source Bibcode
1972AJ.....77..797P
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/77/797
IVOA Identifier IVOID
ivo://CDS.VizieR/J/AJ/77/797
Document Object Identifer DOI
doi:10.26093/cds/vizier.50770797

Access

Web browser access HTML
http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/77/797
https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/77/797
http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/77/797
IVOA Table Access TAP
http://tapvizier.cds.unistra.fr/TAPVizieR/tap
Run SQL-like queries with TAP-enabled clients (e.g., TOPCAT).
IVOA Cone Search SCS
For use with a cone search client (e.g., TOPCAT).
http://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/77/797/table2?
https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/77/797/table2?
http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/77/797/table2?

History

1999-12-20T10:25:03Z
Resource record created
1999-12-20T10:25:03Z
Created
2013-03-04T06:55:01Z
Updated

Contact

Name
CDS support team
Postal Address
CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France
E-Mail
cds-question@unistra.fr