Astronomical Data Center

ADCADC/CDS Standard Document for Catalog:
/external/radio/E8004/

The ADC has expanded its resources in order to better serve our users, we have developed a new category called "external" to complement our catalogs and journal table directories. You can access the NVSS catalog browser described here through the URL:
http://www.cv.nrao.edu/NVSS/NVSS.html.

The following is an abbreviated "ReadMe" document that describes this external data set.
E/VIII/4   1.4 GHz NRAO VLA Sky Survey (NVSS)     (Condon+ 1998)
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1.4 GHz NRAO VLA Sky Survey (NVSS)
    Condon J.J., Cotton W.D., Greisen E.W., Yin Q.F., Perley R.A., 
    Taylor G.B., Broderick J.J. 
    <Astron. J. 115, 1693 (1998)>
    =1998AJ....115.1693C
================================================================================
ADC_Keywords: radio; External catalog 
Mission_Name: VLA

Location: http://www.cv.nrao.edu/NVSS/NVSS.html

Description:
    
   The NRAO VLA Sky Survey (NVSS) is a radio continuum survey covering the 
   sky north of -40 deg declination. A detailed description appears in the 
   1998 May issue of The Astronomical Journal (Condon, J. J., Cotton, W. D., 
   Greisen, E. W., Yin, Q. F., Perley, R. A., Taylor, G. B., & Broderick, 
   J. J. 1998, AJ, 115, 1693). The NVSS is essentially complete. As of 1998 
   July 8, only 6 of the 217,446 NVSS snapshot fields lack total-intensity 
   images. An additional 2094 fields (1.0% of the sky) have total-intensity 
   but not linear-polarization images. We may reobserve the few remaining 
   fields in the spring of 1999. The principal NVSS data products are:
 
   A set of 2326 continuum map ``cubes,'' each covering 4 deg X 4 deg with 
   three planes containing the Stokes I, Q, and U images. These images were
   made with a relatively large restoring beam (45 arcsec FWHM) to yield the
   high surface-brightness sensitivity needed for completeness and photo
   metric accuracy. Their rms brightness fluctuations are about 0.45 
   mJy/beam= 0.14 K (Stokes I) and 0.29 mJy/beam = 0.09 K (Stokes Q and U). 
   The rms uncertainties in right ascension and declination vary from < 1 
   arcsec for relatively strong (S > 15 mJy) point sources to 7 arcsec for the 
   faintest (S = 2.3 mJy) detectable sources. The completeness limit is about
   2.5 mJy. 

   A catalog of discrete sources on these images (nearly 2 million sources in 
   the entire survey). 
 
   Processed (u,v) data sets. Every large image was constructed from more than
   100 smaller "snapshot" images. All of the edited and calibrated single-
   source (u,v) data sets used to make the snapshot images contributing to 
   each large image have been combined into a single multisource (u,v) file
   for users who want to investigate the data underlying the images. 

   Historical notes:
      3-June-1999, by Gail L. Schneider: Updated source reference and 
      description.


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(End)               Gail L. Schneider  (ADC/SSDOO)                 11-May-1998
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