The VLSS Bright Source Spectral Catalog
published as: "Radio Frequency Spectra of 388 Bright 74 MHz Sources"
   <2008, ApJS 174, 313>

    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.