Detailed Description of VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)

VIII/65             1.4GHz NRAO VLA Sky Survey (NVSS)      (Condon+ 1998)
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The NRAO VLA Sky Survey
     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
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ADC_Keywords: Radio sources ; Radio continuum ; Surveys


Description:
    The NRAO VLA Sky Survey (NVSS) is a radio continuum survey covering
    the sky north of -40° declination at 1.4GHz. The principal data
    products of the NVSS are a set of 2326 4x4° continuum "cubes" with
    three planes containing Stokes I, Q, and U images, plus a catalog of
    almost 2 million discrete sources stronger than a flux density of
    about 2.5mJy.

    The images all have 45 arcsecond FWHM angular resolution and nearly
    uniform sensitivity. Their rms brightness fluctuations are
    approximately 0.45mJy/beam=0.14K (Stokes I) and 0.29mJy/beam=0.09K
    (Stokes Q and U). The rms uncertainties in right ascension and
    declination vary from <= ~1arcsecond for the 400,000 sources stronger
    than 15mJy to 7arcseconds at the survey limit.

    A more detailed description is provided in the printed paper and at the
    NVSS website at           http://www.cv.nrao.edu/nvss/
    where all data products, user software, and updates were released as
    soon as they were produced and verified.

File Summary:

       FileName      Lrecl  Records   Explanations

×                   80        .   This file
× ReadMe            80        .   This file
× nvss.dat         158  1773484   The NVSS Catalog


See also:
    VIII/59 : the FIRST Survey, version 1999Jul (White+ 1999)
    http://www.cv.nrao.edu/nvss/ : the NVSS Home Page


Byte-by-byte Description of file:  nvss.dat

   Bytes Format Units    Label   Explanations

   1-  8  A8    ---      Field   Name of the original survey image field
                                 from which the component was derived.
  10- 16  F7.2  pix      Xpos    X position (RA direction) of the radio source
  18- 24  F7.2  pix      Ypos    Y position (Dec direction) of the radio source
  26- 39  A14   ---      NVSS    Source name (1)
  41- 42  I2    h        RAh     Right Ascension J2000 (hours) (2)
  44- 45  I2    min      RAm     Right Ascension J2000 (minutes) (2)
  47- 51  F5.2  s        RAs     [0,60] Right Ascension J2000 (seconds) (2)
      53  A1    ---      DE-     Declination J2000 (sign) (2)
  54- 55  I2    deg      DEd     Declination J2000 (degrees) (2)
  57- 58  I2    arcmin   DEm     Declination J2000 (minutes) (2)
  60- 63  F4.1  arcsec   DEs     [0,60] Declination J2000 (seconds) (2)
  65- 69  F5.2  s        e_RAs   Mean error on RA
  71- 74  F4.1  arcsec   e_DEs   Mean error on Dec
  76- 83  F8.1  mJy      S1.4    Integrated 1.4GHz flux density of radio source
  85- 91  F7.1  mJy      e_S1.4  Mean error on S1.4
      93  A1    ---   l_MajAxis  Limit flag on MajAxis
  94- 98  F5.1  arcsec  MajAxis  Fitted (deconvolved) major axis of radio source
     100  A1    ---   l_MinAxis  Limit flag on MinAxis
 101-105  F5.1  arcsec  MinAxis  Fitted (deconvolved) minor axis of radio source
 107-111  F5.1  deg      PA      [-90, 90]? Position angle of fitted major axis
 113-116  F4.1  arcsec e_MajAxis  ? Mean error on MajAxis
 118-121  F4.1  arcsec e_MinAxis  ? Mean error on MinAxis
 123-126  F4.1  deg      e_PA    ? Mean error on PA
 128-129  A2    ---   f_resFlux  [PS* ] Residual Code (3)
 131-134  I4    mJy     resFlux  ? Peak residual flux, in mJy/beam (3)
 136-141  F6.2  mJy     polFlux  ? Integrated linearly polarized flux density
 143-147  F5.1  deg      polPA  *[-90,90]? The position angle of polFlux (4)
 149-153  F5.2  mJy   e_polFlux  ? Mean error on polFlux
 155-158  F4.1  deg     e_polPA  ? Mean error on polPA

Note (1):
    The NVSS Catalog designation is of the form
        NVSS JHHMMSS+DDMMSS
    using the standard IAU nomenclature prescription, where NVSS is the
    catalog acronym, J specifies the coordinate equinox (for J2000)
    HHMMSS are the hours, minutes, and truncated (not rounded) seconds of
    right ascension, + or - is the sign of the declination, and DDMMSS are
    the degrees, arcminutes, and truncated (not rounded) arcseconds of
    declination. Thus, the NVSS source at equinox J2000.0 coordinates of
    00h00m00.24s -20d04'49.1" is called NVSS J000000-200449. This name,
    without the leading "NVSS J" prefix, is reported in the NVSS column.
    There are four cases where a suffix "a" or "b" have been appended to
    the name to ensure the naming unicity.
Note (2): Position of the centroid of the fitted radio source,
    for the epoch of observation (1995±2).
Note (3): High residual values generally indicate complex sources.
    f_resFlux contains a flag indicating a residual of the fit to the
    radio source, which can be:
      P: if the peak flux density residual was high
      S: if the integrated flux density residual was high
Note (4):
    polPA is the position angle (N through East) of the "E" vector of the
    linear polarization if the source was detected (1 sigma) in linear
    polarization.


History:
    The file "nvss.dat" was created from the ascii edition of NVSS as file
    ftp://ftp.cv.nrao.edu/nvss/CATALOG/NVSSCatalog.text.gz  (27-Sep-2002),
    provided by the NVSS Catalog's authors.
    Many of the descriptions enclosed in this ReadMe file were prepared
    by the HEASARC team at
    http://heasarc.gsfc.nasa.gov/W3Browse/all/nvss.html
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(End)                                   Francois Ochsenbein [CDS]    24-Dec-2002