Access to Astronomical Catalogues

VIII/17         The North 20cm Survey                     (White+ 1992)
The 1.4-GHz Northern Sky Catalog
    White R.L., Becker R.H.
   <Astrophys. J. Suppl. Ser. 79, 331 (1992)>
   =1992ApJS...79..331W
ADC_Keywords: Radio sources


Description:
    This catalog contains a list of 30239 radio sources at 1.4GHz over the
    declination  range of -5 to +82 degrees.  This catalog is based on the
    Green  Bank 1.4GHz Northern  Sky Survey (Condon  and Broderick,  1986,
    Cat.  VIII/6)  which was generated using the Green Bank 300 foot (91m)
    telescope. The threshold for identifying a 1.4GHz radio source was set
    at 100mJy. The catalog data include the source name, a confusion flag,
    right  ascension (1950),  declination (1950),  1.4GHz flux,  a flag to
    indicate if the source is extended at 20cm,  4.85GHz flux (from Becker
    et  al.,  1991,  Cat.  VIII/13),  a flag  to indicate if the source is
    extended  at 6cm,  365MHz flux (from the Texas Survey,  Douglas et al.
    1980;   see Cat.  VIII/42)),  spectral index between 6 and 20 cm,  and
    spectral index between 20 and 80 cm.  Where possible,  the source name
    is derived from the 6cm catalog of Becker et al. 1991 (Cat. VIII/13).

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
north20.dat       69    31524   The 20cm catalog


Byte-by-byte Description of file: north20.dat

   Bytes Format  Units  Label    Explanations

   1- 10  A10    ---    WB      *20cm Name
      12  A1     ---    cFlg    *[?] Confusion flag
  14- 15  I2     h      RAh      Hours of right ascension (1950)
  17- 18  I2     min    RAm      Minutes of RA
  20- 23  F4.1   s      RAs      Seconds of RA
      25  A1     ---    DE-      Sign of declination
  26- 27  I2     deg    DEd      Degrees of declination (1950)
  29- 30  I2     arcmin DEm      Minutes of declination
  32- 33  I2     arcsec DEs      Seconds of declination
  35- 41  I7     mJy    S1.4     1.4GHz (20cm) flux
      42  A1     ---    n_S1.4   [*] if source is extended at 20cm, else blank
  44- 50  I7     mJy    S4.85    ? 4.85 GHz flux from Becker et al (Cat. VIII/13)
      51  A1     ---    n_S4.85  [*] if source is extended at 6cm, else blank
  53- 59  I7     mJy    S.365    ? 365MHz (80cm) flux from Texas survey, Douglas 
                                 et al. (see Cat. VIII/42)
  61- 64  F4.1   ---   Sp+Index *? Spectral index between 6 and 20cm
  66- 69  F4.1   ---  Sp+Index2 *? Spectral index between 20 and 80cm

Note on WB:
    20cm Name, constructed from RA, Dec HHMM+DDMM with A or B added at end
    if needed to make name unique. When a 20cm source matches a sources in
    the 6cm catalog of Becker, White & Edwards (1991, Cat. VIII/13) the
    6cm name and position (good to 40" at the 90% confidence level) are
    used. Sources without a 6cm counterpart have names ending in L; their
    positions are only accurate to 160" at the 90% confidence level).
Note on cFlg:
    ? indicates that a 20cm source matched more than one 6cm or 80cm
    source, so confusion is likely. In that case the additional matches
    are listed in following lines.
Note on Sp+Index, Sp+Index2:
    The values are blank if the source was not detected at 6cm/80cm.
    The spectral index (alpha) is defined such that
        S(nu) ∝ (nu)α


References:
   Becker, R.H., White, R.L. and Edwards, A.L. 1991, ApJS, 75, 1
      (Cat. VIII/13)
   Condon, J.J., and Broderick, J.J. 1986, AJ, 91, 1051
      (Cat. VIII/6)
   Douglas, J.N., Bash, F.N., Torrence, G.W., and Wolfe, C. 1980,
     Univ. Tex., Publ. Astron., No. 17 (see Cat. VIII/42)
   Condon. J.J., and Broderick, J.J. 1985, AJ, 90, 2540 (Cat. VIII/6)
(End)                        C.-H. Joseph Lyu [Hughes STX/NASA]      01-Aug-1995