VII/26D     Uppsala General Catalogue of Galaxies (UGC)     (Nilson 1973)
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Uppsala General Catalogue of Galaxies (UGC)
     Nilson P.
     
     =1973ugcg.book.....N         (SIMBAD/NED BibCode)
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ADC_Keywords: Galaxy catalogs

Description: 
    The Uppsala General Catalogue of Galaxies (UGC) is an essentially
    complete catalogue of galaxies to a limiting diameter of 1.0' and/or
    to a limiting apparent magnitude of 14.5 on the blue prints of the
    Palomar Observatory Sky Survey (POSS). Coverage is limited to the sky
    north of declination -02.5degrees. Galaxies smaller than 1.0' in
    diameter but brighter than 14.5 mag may be included from the Catalogue
    of Galaxies and of Clusters of Galaxies (CGCG, Zwicky et al.
    1961-1968); all such galaxies in the CGCG are included in the UGC. The
    galaxies are ordered by 1950 right ascension.

    The catalogue contains descriptions of the galaxies and their
    surrounding areas, plus conventional system classifications and
    position angles for flattened galaxies. Galaxy diameters on both the
    blue and red POSS prints are included and the classifications and
    descriptions are given in such a way as to provide as accurate an
    account as possible of the appearance of the galaxies on the prints.
    Only the data portion of the published UGC is included in the
    machine-readable version.

    The order of the records is strictly by UGC number; i.e., the Addenda
    records follow their main catalogue counterparts in the file. The
    colons (indicating uncertainty) and various other codes (parentheses,
    brackets) are not included in the machine-readable version of the
    catalogue. Several possible improvements to the catalogue might
    consist of adding codes corresponding to the published version, a
    second file containing abbreviations and terminology and a third file
    with the extensive notes. It would also be important to add an
    asterisk or some other code to data records having a note in the
    proposed third file.

    This document describes the machine-readable version of the UGC as
    distributed by the Astronomical Data Centers. It is intended to enable
    users to read and process the data without problems or guesswork. For
    additional details regarding the classifications, measurement of
    apparent magnitudes, and data content, the source reference should be
    consulted. A copy of this document should accompany any
    machine-readable copy of the catalogue.


File Summary:
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 FileName        Lrecl       Records    Explanations
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ReadMe              80             .    This file
catalog.dat         81         12940    UGC catalogue
errors.dat          42           134    The changes made by the ADC in 1995
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Byte-by-byte Description of file: catalog.dat 
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   Bytes Format  Units   Label    Explanations
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   1-  3  A3     ---     UGCtext  "UGC"
   5-  9  I5     ---     UGC      [1/12921]+= UGC number
      10  A1     ---     A        [A] "A" if the galaxy is from the Addenda
                                      list of the published catalogue;
                                      otherwise blank.
  11- 12  I2     h       RAh      Right Ascension 1950 (hours)
  13- 16  F4.1   min     RAm      Right Ascension 1950 (minutes)
      17  A1     ---     DE-      Declination 1950 (sign)
  18- 19  I2     deg     DEd      Declination 1950 (degrees)
  20- 21  I2     arcmin  DEm      Declination 1950 (minutes)
  22- 34  A13    ---     MCG      MCG designation (1)
  35- 38  I4     ---     POSS     Number of the POSS field in which the
                                     galaxy is best visible.
  39- 44  F6.2   arcmin  MajAxis  ? Major axis of the galaxy as measured on
                                     the POSS blue print. (2)
  45- 49  F5.2   arcmin  MinAxis  ? Minor axis of the galaxy as measured on
                                     the POSS blue print. (2)
  50- 52  I3     deg     PA       [0/180[? Position angle measured in the
                                     conventional manner from North through
                                     East. (3)
  53- 59  A7     ---     Hubble   Classification in the Hubble system or
                                     remarks, in a free field format,
                                     including lower case designations.
  61- 64  F4.1   mag     Pmag     ? Photographic magnitude mpg , recorded to
                                     precision given in published catalogue;
                                     i.e., if tenths not reported, byte 64 is
                                     blank.
  65- 69  I5     km/s    RadVel   ? Radial velocity corrected for Solar
                                     motion (4)
  70- 75  F6.2   arcmin  aR       ? Major axis of the galaxy as measured on
                                     the POSS red print. (2)
  76- 80  F5.2   arcmin  bR       ? Minor axis of the galaxy as measured on
                                     the POSS red print. (2)
      81  I1     ---     i        [0/7]? Inclination to the line of sight for
                                     spirals (5)
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Note (1): The Morphological Catalogue of Galaxies (MCG) 
    (Vorontsov-Velyaminov et al. 1962, 1963, 1964, 1968). The first number
    of the designation is the Palomar Observatory Sky Survey (POSS) 6deg
    zone, from the equator +00 to the north celestial pole +15; the second
    number is the POSS field along the zone, while the third number is the
    galaxy in this field in the MCG. Non-MCG galaxies are assigned the
    number 000 in the third position, but the first and second values are
    given correctly.
Note (2): The precision to which diameters are recorded matches the
    published catalogue; additional decimal places are blank, but colons,
    brackets and parentheses are not included in the computerized
    catalogue.
Note (3): Colons, parentheses and brackets in the published catalogue
    are not included here. Blank if data not present.
Note (4): Radial Velocity is relative to the Local Group according to
    V0 = 300 cos A, where A is the distance to the conventional Solar
    apex at lI=55deg, bI=0deg or lII = 87deg bII = +1deg. If the
    uncertainties in the measurements were considered too large to make
    corrections meaningful, usually only the uncorrected value is given.
Note (5): Inclination measured on a scale from 1 (face-on) to 7 (edge-on).
    For galaxies of high inclination, a value is calculated from the
    Hubble formula n - 10(a-b)/a [a - major axis, b - minor axis]. The
    value 7 denotes objects inclined not more than a few degrees to the
    line of sight.
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Byte-by-byte Description of file: errors.dat 
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   Bytes Format   Units   Label   Explanations
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   1-  5  I5      ---     ID      Number of entry
       6  A1      ---     IDs     Suffix for entry number  
   7-  9  A3      ---     field   Field in error
  11- 20  A10     ---     old     Old entry
  22- 42  A21     ---     new     New entry and comments
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Historical Notes:
    The magnetic tape version of the Uppsala General Catalogue of Galaxies
    was received from Dr. Robert S. Dixon of the Ohio State University
    Radio Observatory on 7 December 1981. As received, the catalogue
    consisted of 12,942 logical records of length 90 bytes. Each logical
    record contained a sequential counter on bytes 85-90, while bytes
    81-84 and single columns throughout the records were not used. There
    was also only a five-byte allowance for the major axis of the galaxy
    as measured on the red POSS print, a field too small to accommodate
    U00454 (M31), which has a major axis of 200:' (in order to fit the
    200' value, the radial velocity had been moved left one byte, thus
    making it read -2990 km/sec instead of the correct value of -299
    km/sec). The following modifications were made to the catalogue to fix
    the above items, correct several errors, and to maximize storage
    efficiency. Except for item 10, these modifications were made by Francois
    Ochsenbein at the CDS.

  1.The published edition contains 12,921 objects in the main catalogue
    and 19 addenda; hence, with 12,942 records on the tape there were
    obviously a few duplicates. The records for UGC 3944 and UGC 6063A
    were found to be repeated and the duplicates were deleted.

  2.A check for the addenda objects resulted in the discovery of a missing
    A for UGC 7399A--this was added.

  3.Upon examination of the original file version of the catalogue
    supplied to him, Mr. Marion Schmitz discovered the misnumbering of UGC
    12417 and UGC 12418 as UGC 12447 and UGC 12448--these errors were
    corrected.

  4.The data record for UGC   253 was found to have a hexadecimal code "AA"
    character (equivalent to a down-arrow in the classification field (bytes
    46-52) in place of a lower case "b" (Sb/SB(down-arrow) instead of
    Sb/SBb)--this was corrected.

  5.The data field for the major axis as measured on the red POSS print
    was expanded to six bytes and the record for UGC 454 (discussed above)
    corrected.

  6.All superfluous blanks were removed to decrease the logical record
    length from 90 bytes to 74 bytes (counting also the removal of the
    sequential numbers originally in bytes 85-90).

  7.UGC and MCG catalog designations were altered to their present format,
    extending the record length to 81 bytes.

  8.(Version C, made at CDS, August 1993)
    a. The error reported by Carlo Giovanardi in "ADC Newsletter" 2.2
       (April 1993) was corrected (RAh column)
    b. The position of the minor axis blue in UGC 326 which was shifted
       has been fixed.
    c. All records with radial velocities larger than 10000 km/s expanded
       over the red major axis column; the + sign in column 65 was
       therefore removed for the following galaxies:
         UGC   262  UGC   545  UGC  1095  UGC  4093  UGC  5408  UGC  6514
         UGC  8058  UGC  8327  UGC  8696  UGC  8811  UGC  8825  UGC  9509
         UGC 10099  UGC 10170  UGC 10180  UGC 10188  UGC 10189  UGC 10191
         UGC 10192  UGC 10199  UGC 10635  UGC 11130  UGC 11763  UGC 12397
    d. UGC Number 20016 should be read 12016
       Position angles for UGC 153, 341 and 388 were corrected
      (S. Nishimura, on 30-Aug-1993)

  9.(Version D, made at CDS September 1995, following comments by
     Ralph Pass ), typo errors in UGC numbers:
          4500  5228  5258  7307 10374 10377 10848 11718 11748 12342 12392
         12847 12848 12817 12818 12843 12873

  10.At least one error may have been corrected inappropriately. UGC5206 and 
    5854A are both given as MGC+02-28-002 but UGC 5206 is at RA=0941.7 
    while the MGC galaxy is at RA=1041.7. 5854A is at that location. It 
    was assumed that these referred to the same galaxy. Hence UGC5854A 
    was deleted and the RA changed for UGC5206 by the undersigned.
    She also moved two records which were out of order to the proper position. 

Acknowledgments:
    The present version includes a few corrections inserted by CDS (see 
    Remarks, Modifications, points 8 and 9) compared to the CD-ROM
    "Selected Astronomical Catalogs Volume 1" edited by the
    Astronomical Data Center, NASA, 1992. It also contains a number of
    corrections inserted by the undersigned. The latter are listed in
    errors.dat.

    Points 8 and 9, the "File Summary" and the
    "Byte-by-byte Description" were prepared by Francois Ochsenbein of
    the CDS. The file errors.dat and minor modifications to this 
    acknowledgment were prepared by the undersigned. Otherwise, the 
    documentation herein is from Wayne H. Warren Jr. (1982).
    The latter expressed appreciation to Dr. R. S. Dixon for supplying the
    original tape version of the UGC, and to Mr. M. Schmitz for pointing
    out the errors that he discovered in the UGC numbers (point 3 above).

    Nancy G. Roman expresses appreciation particularly to Mark Anderson 
    who did an extensive analysis of the catalog. Others errors were 
    reported by Ralph Pass, Carlo Giovanardi, and James Himer. All have 
    been checked and most reported errors were correct as reported. 

References:
  Nilson, P. 1973, Uppsala General Catalogue of Galaxies, Uppsala
    Astron. Obs.  Ann. 6.
  Vorontsov-Velyaminov, B. A., Krasnogorskaya, A. and Arhipova, V. P.
    1962-1968, Morphological Catalogue of Galaxies, 4 Volumes (Moscow:
    Sternberg Institute 32, 33, 34, 38).
  Warren, W.H. Jr 1982, "Documentation for the Machine-Readable Version
    of the Uppsala General Catalogue of Galaxies", NSSDC/WDC-A-R&S 82-30,
    National Aeronautics and Space Administration, Goddard Space Flight
    Center, Greenbelt, Maryland 20771
  Zwicky, F. et al. 1961-1968, Catalogue of Galaxies and of Clusters of
    Galaxies, I-VI (Pasadena: California Institute of Technology).
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(End)                 Nancy Grace Roman    [ADC/SSDOO]    20-Oct-1995