ACDS V10.0 - Detailed Description of VII/26D

ACDS V10.0 - Sun Jan 19 14:49:21 CET 2025

| # Detailed Description of VII/26D : Uppsala General Catalogue of Galaxies (UGC) (Nilson 1973) |

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.

    VII/26D     Uppsala General Catalogue of Galaxies (UGC)     (Nilson 1973)
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    Uppsala General Catalogue of Galaxies (UGC)
         Nilson P.
         <Uppsala Astron. Obs. Ann. 6 (1973)>
         =1973UGC...C......0N         (SIMBAD/NED BibCode)
    ================================================================================
    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:

           FileName      Lrecl  Records   Explanations

    ×                   80        .   This file
    × ReadMe            80        .   This file
    × catalog.dat       81    12939   UGC catalogue
    × errors.dat        49      133   The changes made by the ADC in 1995

    See also:
        J/ApJS/125/409 : Arcsecond positions of UGC galaxies     (Cotton+ 1999)

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

       Bytes Format  Units   Label    Explanations

       1-  3  A3     ---     ---      [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)

    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.
        See also other values in VII/36
    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.

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

       Bytes Format  Units   Label    Explanations

       1-  5  I5     ---     UGC      Number of entry
           6  A1     ---     A        [A] 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

    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 rppass@rppass.com), 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-per-byte Description" were prepared by Francois Ochsenbein of
        the CDS. The file errors.dat and minor modifications to this
        acknowledgement 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). (Catalogue VII/62)
      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).
        (Catalogue VII/49)
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    (End)                 Nancy Grace Roman    [ADC/SSDOO]               20-Oct-1995