ACDS V10.0 - Detailed Description of VIII/84

ACDS V10.0 - Sun Jan 19 19:12:26 CET 2025

| # Detailed Description of VIII/84 : A final non-redundant catalogue for 7C 151-MHz survey (Hales+ 2007) |

Note : this is the description file of the original catalog. This HTML page corresponds well to the original description, but some minor changes in the format may have been introduced in the FITS output files in order to allow for arithmetic operations on quantities such as coordinates and times. h:m:s and d:m:s units are normally converted into degrees, and YYYY-MM-DD into julian days.
Similarly, some slight changes may have been introduced in the units; the value given in the HTML files supersedes the value indicated in the ReadMe file for this catalogue.

    VIII/84   A final non-redundant catalogue for 7C 151-MHz survey (Hales+ 2007)
    ================================================================================
    A final non-redundant catalogue for the 7C 151-MHz survey
         Hales S.E.G., Riley J.M., Waldram E.M., Warner P.J., Baldwin J.E.
        <Mon. Not. R. Astron. Soc. 382, 1639 (2007)>
        =2007MNRAS.382.1639H
    ================================================================================
    ADC_Keywords: Radio sources ; Surveys

    Keywords: catalogues -  surveys - radio continuum: general

    Description:
        We present a final unified catalogue for the 7C survey at 151 MHz with
        resolution 70x70cosec(dec) arcsec2. This has been constructed by
        amalgamating the existing catalogues derived from individual fields
        imaged at this resolution and eliminating redundancy in regions of
        mutual overlap. This is a non-trivial procedure because the flux in
        multiple-component sources may be fitted differently on alternative
        images, owing, for example, to differences in local noise and beam
        distortion. The final catalogue thus produced contains 43683 sources.

        Separate final catalogues have been published for the 7C Galactic
        Plane survey (7CG, see Cat. J/MNRAS/294/607) and the lower-resolution
        survey of the low-declination strip 9h<RA<16h, 20deg<Dec<35deg (Cat.
        J/MNRAS/282/779).

        The individual catalogues for about 40 of the regions contributing to
        the total have already been published, together with full details of
        the methodology, in MNRAS or A&AS:

        Lacy et al. 1995, MNRAS, 276, 614   (=1995MNRAS.276..614L) (#92 below)
        Visser et al. 1995, A&AS, 110, 419  (=1995A&AS..110..419V) (#93 below)
        Pooley et al. 1998, MNRAS, 298, 637 (=1998MNRAS.298..637P) (#94-96 below)
        Riley et al. 1999, MNRAS, 306, 31   (=1999MNRAS.306...31R) (# 1-33 below)

        and these data are also available via the MRAO website at
        http://www.mrao.cam.ac.uk/surveys/7C/

        Individual catalogues for the remaining 58 regions by Riley et al.
        (#34-91 below) were released electronically via the MRAO website in
        November 2001. These include a re-analysis of data originally
        published in rather a different parametrization by McGilchrist et al.
        1990, MNRAS, 246, 110 (=1990MNRAS.246..110M) The regions re-analyzed
        are those numbered #41,44,59,60,62 and 63 below and they supersede
        McGilchrist's 1990 publication.

        The RAxDec coverage, average rms noise, flux density of the faintest
        source listed and completeness limit for each of the individual
        regions contributing to the final catalogue are given in the table
        "regions.dat".

        1-sigma errors on the listed source positions may be approximated by:

            RA..error(arcsec) = SQRT(1.0**2 + (32/SNR)**2)
            Dec.error(arcsec) = Kcosec(dec) x (RA error)

        where (approx) K= 1.0 around dec 70, increasing to 1.3 below dec 50,
        and 1-sigma errors on the listed flux densities may be approximated by:

            Error on S beam-fitted(Jy)  =  SQRT(0.03**2 + SNR**-2) x S(Jy)
            Error on SINT(Jy) = 1.5 x SQRT(0.03**2 + SNR**-2) x SINT(Jy)

        where SNR, S and SINT correspond to the columns denoted by those names
        in the byte-by-byte description below. For multi-component sources the
        SNR for the brightest component is used to estimate the SINT error.

        For further details of the surveys and data analysis procedures please
        refer to the published papers referenced at the head of this file and
        references therein.

    File Summary:

           FileName      Lrecl  Records   Explanations

    ×                   80        .   This file
    × ReadMe            80        .   This file
    × 7c.dat            86    43683   7C sourcelist of 43683 sources
    × regions.dat       52       96   List of fields observed

    See also:
       J/MNRAS/282/779 : 7C: 151-MHz survey of region 9-16h 20-35deg (Waldram+ 1996)
       J/MNRAS/294/607 : 7C(G) 151MHz survey of the Galactic plane (Vessey+ 1998)

    Nomenclature Note:
       Sources of the 7C catalogue should be designated with their full
       B1950 beam-fitted position with 'format' 7C HHMMSS.s+DDMMSS, e.g.
       7C 001920.0+451334

    Byte-by-byte Description of file:  7c.dat

       Bytes Format  Units   Label   Explanations

       1-  2  I2     h       RAh     Beam-fitted position right ascension B1950
       4-  5  I2     min     RAm     Beam-fitted position right ascension B1950
       7- 10  F4.1   s       RAs     Beam-fitted position right ascension B1950
          12  A1     -       DE-     Beam-fitted position declination (sign)
      13- 14  I2     deg     DEd     Beam-fitted position declination B1950
      16- 17  I2     arcmin  DEm     Beam-fitted position declination B1950
      19- 20  I2     arcsec  DEs     Beam-fitted position declination B1950
      24- 25  I2     h       RAIh    Centroid position right ascension B1950
      27- 28  I2     min     RAIm    Centroid position right ascension B1950
      30- 33  F4.1   s       RAIs    Centroid position right ascension B1950
          35  A1     -       DEI-    Centroid position declination (sign)
      36- 37  I2     deg     DEId    Centroid position declination B1950
      39- 40  I2     arcmin  DEIm    Centroid position declination B1950
      42- 43  I2     arcsec  DEIs    Centroid position declination B1950
      47- 52  F6.3   Jy      S       Beam-fitted flux density, in Jy/beam
      54- 59  F6.3   Jy      Sint    Integrated flux density
      61- 65  F5.1   ---     SNR     Signal-to-noise ratio
      67- 70  F4.1   ---     Extent  Extent of the source
                                        in units of local beam area
          74  I1     ---     Nmax   *Number of local maxima within the
                                        integrated region
      76- 79  I4     ---     ICOMP  *Serial number identifying complex source
                                        (set to 0 if Nmax=1)
      81- 86  I06    ---     Map    *Field from which data record originates

    Note on Nmax and ICOMP:
         ICOMP is a serial number denoting a particular complex source - it
         has the same value for all the Nmax components (local maxima) which
         belong to that particular source, allowing the user to associate
         its individual components listed in the catalogue, no matter how
         the catalogue is ordered. Nmax specifies the total number of components.
         For a source with only one component  Nmax=1 and ICOMP is set to 0
    Note on Map:
         Field from which data record originates with + sign excluded,
         e.g. Map 072245 denotes the region 0722+45

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

       Bytes Format Units   Label     Explanations

       1-  2  I2    ---     Reg       Region number
       4-  9  I06   ---     Map       Name of map
          11  A1    ---     r_Map     [*a-e] Origin of the region data (1)
      14- 15  I2    h       RA1.h     Coverage RA1-RA2xDE1-DE2 B1950 (2)
      17- 18  I2    min     RA1.m     Coverage RA1-RA2xDE1-DE2 B1950 (2)
          20  A1    ---     ---       [-]
      22- 23  I2    h       RA2.h     Coverage RA1-RA2xDE1-DE2 B1950 (2)
      25- 26  I2    min     RA2.m     Coverage RA1-RA2xDE1-DE2 B1950 (2)
          27  A1    ---     DE1.-     Coverage RA1-RA2xDE1-DE2 B1950 (2)
      28- 29  I2    deg     DE1.d     Coverage RA1-RA2xDE1-DE2 B1950 (2)
      31- 32  I2    arcmin  DE1.m     Coverage RA1-RA2xDE1-DE2 B1950 (2)
          34  A1    ---     ---       [-]
          35  A1    ---     DE2.-     Coverage RA1-RA2xDE1-DE2 B1950 (2)
      36- 37  I2    deg     DE2.d     Coverage RA1-RA2xDE1-DE2 B1950 (2)
      39- 40  I2    arcmin  DE2.m     Coverage RA1-RA2xDE1-DE2 B1950 (2)
      43- 44  I2    mJy     Noise     Average rms noise before primary beam
                                       correction
      46- 48  I3    mJy     Sfaint    Flux density of the faintest source listed
      50- 52  I3    mJy     Scomp     Completeness limit

    Note (1): Origin for the region data as follows:
          a = from Riley et al. 1999MNRAS.306...31R (1-33)
          b = from Riley et al. 2001: 58 regions at (34-91)
                   www.mrao.cam.ac.uk/surveys/7C/
          c = from Lacy et al. 1995MNRAS.276..614   (92)
          d = from Visser et al. 1995A&AS..110..419 -
                   an amalgamation of seven pointings   (93)
          e = from Pooley et al. 1998MNRAS.298..637  (94-96)
          * = 150056 corrupted replaced by 150060
              (an amalgamation of data from unpublished regions 144060, 152060)
    Note (2): RA coverage is indicated by approx RA range at Dec of field centre.
              Dec coverage is indicated by approx Dec range at RA of field centre.

    History:
      * 24-Jan-2008: a spurious negative value of Nmax in row 28028 of
                     7c.dat was corrected on 24-Jan-2008
    ================================================================================
    (End)                                Sally Hales [MRAO]              25-Jan-2008