The VLSS Bright Source Spectral Catalog
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published as: "Radio Frequency Spectra of 388 Bright 74 MHz Sources"
   <2008, ApJS 174, 313>
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Abstract:
    As a service to the community, we have compiled radio frequency
    spectra from the literature for all  sources within the VLA Low
    Frequency Sky Survey (VLSS) that are brighter than 15 Jy at 74
    MHz.  Over 160 references were used to maximize the amount of
    spectral data used in the compilation of the spectra, while also
    taking care to determine the corrections needed to put the flux
    densities from all reference on the same absolute flux density
    scale.  With the new VLSS data, we are able to vastly improve
    upon previous efforts to compile spectra of bright radio sources
    to frequencies below 100 MHz because (1) the VLSS flux densities
    are more reliable than those from some previous low frequency
    surveys and (2) the VLSS covers a much larger area of the sky
    (Dec. > -30 deg.) than many other low frequency surveys
    (e.g., the 8C survey).  In this paper, we discuss how the spectra
    were constructed and how parameters quantifying the shapes of the
    spectra were derived.  Both the spectra and the shape parameters
    are made available here to assist in the calibration of observations
    made with current and future low frequency radio facilities.

File Summary:

    FileName      Lrecl  Records   Explanations

bcat_spec.pos      58    388   List of source names and positions
bcat_spec.dat      45   5737   Catalog of spectral data from the literature
bcat_rsfit.dat     68    388   Table of parameters from spectral fits


Byte-by-byte Description of file:  bcat_spec.pos

   Bytes Format Units     Label    Explanations

   1-  9  A9    ---       Name     Source Name
  11- 20  A10   ---       RA       Sexigesimal Right Ascension J2000 (hh:mm:ss.s)
  22- 32  A11   ---       Dec      Sexigesimal Declination J2000 (dd:mm:ss.s)
  34- 58  A25   ---       AltNam   Alternative Name from NED Search


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

   Bytes Format Units     Label    Explanations

   1-  9  A9    ---       Name     Source Name
  11- 15  I5    MHz       Freq.    Frequency
  19- 30  E12.6 Jy        Sint     Integrated Flux Density (on Baars et al. 1977 scale)
  34- 45  E12.6 Jy        e_Sint   One-sigma Uncertainty in Integrated Flux Density


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

   Bytes Format Units     Label    Explanations

   1-  9  A9    ---       Name     Source Name
  11- 12  I2    ---       NFreq    Number of Frequencies with Flux Densities > 0
  14- 19  F6.1  Jy        S74      Integrated Flux Density at 74 MHz
  22- 26  F5.2  ---       Alph_hi  Spectral Index for Freq. > 300 MHz from Linear Fit
  28- 33  F6.1  Jy        S74_int  Flux Density at 74 MHz Interpolated Using Linear Fit to freq. > 300 MHz
  35- 40  F6.2  dex       A        Parameter A from Fitting Equation (1) to Spectrum
  42- 47  F6.2  ---       B        Parameter B from Fitting Equation (1) to Spectrum
  49- 54  F6.2  dex       C        Parameter C from Fitting Equation (1) to Spectrum
  56- 61  F6.2  ---       D        Parameter D from Fitting Equation (1) to Spectrum
  64- 68  F5.3  dex       rmsFit   The rms Difference Between the Best Fit and the Data

NOTE: Equation (1) is Y = A + B*X + C*exp(D*X), where Y = log10(S/1 Jy) and
      X = log10(Freq./74 MHz).  For sources where a simple power-law (i.e., Y = A + B*X)
      provided a better fit, only A and B are given.