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VIII/37             The Third Bologna Survey  (B3)  (Ficarra+ 1985)
================================================================================
Third Bologna Survey at 408 MHz
     Ficarra A., Grueff G., Tomassetti G.
    <Astron. Astrophys. Suppl. Ser. 59, 255 (1985)>
    =1985A&AS...59..255F
================================================================================
ADC_Keywords: Radio sources ; Surveys
Keywords: radio telescope - radio sources - catalog

Description:
    This catalogue contains the first section of a sky survey performed at
    408MHz  with the  'Northern Cross'  Radiotelescope. It  contains about
    13.000  radiosources.  Although  sources  down  to  about  70mJy  were
    measured, only sources  brighter  than  0.10Jy  are  retained  in  the
    catalogue.  According  to  our  estimate  of  confusion  errors,  this
    corresponds to  a detection threshold  of about 5{sigma}.  The list is
    meant to include all the sources with a measured flux S>0.10Jy, in the
    sky area included between the declinations +37{deg}15' and +47{deg}37',
    epoch 1978.0. A number of zones however are affected by interferences,
    malfunctions, etc. The principal one is centered about the radiosource
    Cyg  A, which is itself in the map, but not in the catalogue. The zone
    between  RA  19h30m to 20h30m  is  entirely  lacking,  due  to  strong
    confusion. In the zone from  19h00m  to  19h30m  and  from  20h30m  to
    21h00m,  only sources  brighter than  0.75Jy are  listed, and  to this
    level   the  catalogue  is  espected  to  be  complete.  For  detailed
    discussion of the completeness  of  the  catalogue  see  the  original
    publication cited above.

File Summary:
--------------------------------------------------------------------------------
  FileName        Lrecl  Records   Explanations
--------------------------------------------------------------------------------
ReadMe             80        .   This file
b3.dat             48    13340   The Bologna Third Catalogue
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See also:
    VIII/36 : The Second Bologna Servey (B2)

Byte-by-byte Description of file: b3.dat
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   Bytes Format Units   Label     Explanations
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   1-  9  A9    ---     B3        Source name, (IAU-style), eventually followed
                                   by a multiplicity letter A, B...
  12- 13  I2    h       RAh       Right Ascension (1950.0)
  14- 15  I2    min     RAm       Right Ascension (1950.0)
  16- 19  F4.1  s       RAs       [0/60] Right Ascension (1950.0)
      20  A1    ---     DE-       [+] Declination sign
  21- 22  I2    deg     DEd       Declination (1950.0)
  23- 24  I2    arcmin  DEm       Declination (1950.0)
  25- 26  I2    arcsec  DEs       Declination (1950.0)
  29- 33  F5.2  Jy      Flux      The source total flux. In the large majority
                                   of cases, this is practically equivalent to
                                   the peak flux
  35- 37  F3.1  ---     Fit       Goodness of the fitting algorithm, related to
                                   the R.M.S. value of te residuals in the
                                   fitting matrix
  39- 42  I4    ---     ACOD1     ? Four digit string indicating source
                                     reliability (1)
      44  A1    ---   n_Diam      [RD] If not blank the source were measured by
                                        a double source algorithm.
                                        R => resolved   D => double
  45- 48  F4.1  arcmin  Diam      ? If the source is double: the separation
--------------------------------------------------------------------------------
Note (1): An algorithm was devised by which every source was marked with a
     four-digit number n1, n2, n3, n4 with each digit indicating a
     separate reason for problems, as follows:
    n1: a disturbing, strong source is present, very close in R.A., or
         very close in DEC. The flux ratio R is indicated by n1 and is
         n1 = R/10, truncated to the integer.
    n2: if non-zero, it indicates that the source lies in the vertical
         part of the cross-shaped area, and in the position of a grating
         response in N-S. It thus indicates a larger chance for the
         source to be spurious. The value itself is the rank of the
         grating response (n2 = 5 means the grating closer to the source,
         etc. down to n2 = 1)
    n3: if non-zero it means that the source is very close to a very
         strong source, although not in the cross-shaped area mentioned
         above. A circular area is defined with radius r=2.8sqrt(R)pix;
         n3 indicates how close the source is to the disturbing source,
         in units of 1/r
    n4: if n4 > 4, it indicates that the source lies within a disturbed
          area with the following code:
          5: solar interferences
          6: sidelobes of Cyg A
          7: supernova remnant G160.4+2.8 (Felli et al., 1977A&AS...27..181F)
          8: supernova remnant G166.0+4.3 (Willis, 1973A&A....26..237W)
          9: man-made interferences
        If n4 < 4, it indicates that n4 (and no more) disturbing sources
         are present. In this case the previous digit refer to the
         stronger disturbing source.
--------------------------------------------------------------------------------

Acknowledgements:
    The file and the basic documentation were kindly provided by
    Marzia Cannizzaro <CANNIZZARO@astbo1.bo.cnr.it> in September 1995.
================================================================================
(End)                                         Patricia Bauer  [CDS]  16-Sep-1997