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STI-T-1-5810-510-87
MERGED CATALOGUE OF GALAXIES
(Kogoshvili 1986)
Documentation for the Machine-Readable Version
April 1987
Anne C. Raugh
Contract NAS 5-28408
Prepared for
National Aeronautics and Space Administration
Goddard Space Flight Center
Greenbelt, MD 20771
Prepared by
ST Systems Corporation
4400 Forbes Blvd.
Lanham, MD 20706
ABSTRACT
________
This document describes the machine-readable version of the "Merged Catalogue
of Galaxies" (Kogoshvili 1986) distributed by the Astronomical Data Center,
NASA Goddard Space Flight Center. This version is an update of the 1975 cat-
alog. Listed are identifications, positions, magnitudes, velocities, radio
fluxes, and morphological data on 31,917 galaxies with declinations between
+90 and -33 degrees. Although the number of sources is the same, this ver-
sion also includes data published from 1973 to 1983. The present document
describes the overall file structure and the individual data fields in de-
tail.
Abstract ii
TABLE OF CONTENTS
_________________
1.0 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.0 STRUCTURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1 Each File as a Whole . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2 Catalog (File 1 of 2) . . . . . . . . . . . . . . . . . . . . . . . 4
2.2.1 General Information . . . . . . . . . . . . . . . . . . . . . . 4
2.2.2 Structural Details . . . . . . . . . . . . . . . . . . . . . . . 7
2.2.3 Classifications, Velocities, and Spectral Details . . . . . . . 12
2.2.4 Multiple System and Interaction Details . . . . . . . . . . . . 17
2.3 References (File 2 of 2) . . . . . . . . . . . . . . . . . . . . . . 21
3.0 HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.1 Remarks and Modifications . . . . . . . . . . . . . . . . . . . . . 22
3.2 References to the Documentation . . . . . . . . . . . . . . . . . . 22
APPENDIX A. CORRECTIONS TO THE COMPUTER-READABLE VERSION . . . . . . . . 23
APPENDIX B. MCG SYMBOLS . . . . . . . . . . . . . . . . . . . . . . . . . 24
Table of Contents iii
LIST OF ILLUSTRATIONS
_____________________
Figure 1. Summary Description of Catalog Files . . . . . . . . . . . . . 3
Figure 2. Catalog Record Format (1 of 4) . . . . . . . . . . . . . . . . 4
Figure 3. Catalog Record Format (2 of 4) . . . . . . . . . . . . . . . . 8
Figure 4. Catalog Record Format (3 of 4) . . . . . . . . . . . . . . . . 12
Figure 5. Catalog Record Format (4 of 4) . . . . . . . . . . . . . . . . 17
Figure 6. Reference Record Format . . . . . . . . . . . . . . . . . . . 21
List of Illustrations iv
1.0 INTRODUCTION
_________________
A COPY OF THIS DOCUMENT SHOULD BE DISTRIBUTED WITH EVERY COPY OF THE
MACHINE-READABLE CATALOG.
1.1 DESCRIPTION
________________
"Merged Catalogue of Galaxies" (MERCG; Kogoshvili 1986) is a compilation of
published data from several catalogs. The present version is an update of
the 1975 version, and includes data published from 1973 to 1983, in addition
to the original catalog data, for 31,917 galaxies with declinations between
+90 and -33 degrees.
The catalog is presented in two files. The first contains the catalog data,
which have been compiled from previously published catalogs. These data in-
clude:
o Designations
o Equatorial coordinates
o Magnitudes and colors
o Angular diameters
o Surface brightness
o Position angles
o Detailed structural descriptions
o Classification in several different systems
o Rotation curve data
o Supernovae dates and counts
o HII regions
o Radio flux densities
o Multiple system membership and interaction details
For the most part, these data are left encoded in the same system used by the
source catalog. This document describes the correspondence between the sym-
bols used in the computer-readable MERCG and those in the source catalogs.
For the full meanings of these symbols, the reader is referred to the pub-
lished sources. A summary of many of the symbols used in the "Morphological
Catalogue of Galaxies" (MCG) is included in this document in Appendix B, "MCG
Symbols."
The second file lists the full forms of the references cited by code number
in the first file. Also included are brief descriptions of the content of
each reference.
Introduction 1
1.2 REFERENCES
_______________
Kogoshivili, N. G. 1986, unpublished documentation supplied with the cat-
alog from the Centre de Donnees Stellaires.
Dreyer, J. L. E. 1895, "Index Catalogue of Nebulae" (IC).
Nilson, P. 1973, "Uppsala General Catalogue of Galaxies" (UGC; Uppsala).
de Vaucoulers, G. and de Vaucouleurs, A. 1964, "Reference Catalogue of
Bright Galaxies" (RC1; Austin: University of Texas Press).
de Vaucoulers, G., de Vaucouleurs, A. and Corwin Jr., H.G. 1976, "Refer-
ence Catalogue of Bright Galaxies" (RC2; Austin: University of Texas
Press).
Vorontsov-Velyaminov, B. A., Krasnogorskaya, A., and Arkhipova, V. P.
1962-68, "Morphological Catalogue of Galaxies" (MCG, 5 volumes; Moscow).
Zwicky, F., Herzog, E., Wild, P., Karpowicz, M., and Kowal, C. 1961-68,
"Catalogue of Galaxies and Clusters of Galaxies" (CGCG, 6 volumes;
Zurich).
Zwicky, F., "Catalogue of Selected Compact Galaxies and Post-Eruptive
Galaxies" (CCG; Zurich: L. Speich).
Introduction 2
2.0 STRUCTURE
______________
2.1 EACH FILE AS A WHOLE
_________________________
The MERCG consists of two files. Figure 1 lists machiine-independant attri-
butes of the tape files. The first file contains the catalog data (Figure 2,
Figure 3, Figure 4, and Figure 5). The second file is a list of references
and code numbers (Figure 6). All records are of fixed length. Details of
every field in each file are given in the sections following.
QUOTES IN ANY OF THE FOLLOWING DESCRIPTIONS COME FROM KOGOSHVILI (1986) UN-
LESS OTHERWISE STATED.
+---------------------------------------------------------------------------+
| |
| Merged Catalogue of Galaxies (MERCG) |
| |
| File Contents Record Logical Record Total Number of |
| Format Length Logical Records |
| |
| 1 Catalog FB 376 31,917 |
| 2 References FB 80 138 |
| |
| FB = Fixed-Block Format |
| |
| Figure 1. Summary Description of Catalog Files |
+---------------------------------------------------------------------------+
There are also attributes that will change from computer to computer. You
will probably have to know these in order to use your copy of the catalog;
therefore, they should have been supplied with your tape. These attributes
are as follows:
o Number of tracks
o Density in bytes per inch
o Block size in bytes
o Number of records in a block
o Number of blocks
o Character code (ASCII or EBCDIC)
You may wish to write down the values for your tape in the list above.
Structure 3
2.2 CATALOG (FILE 1 OF 2)
__________________________
This file contains the catalog data. Unless otherwise indicated, a blank in
any field indicates an absence of data. Because of the large number of data
fields, the description of the record format has been broken down into four
sections. However, there is only one object per record.
2.2.1 GENERAL INFORMATION
__________________________
+---------------------------------------------------------------------------+
| |
| Bytes FORTRAN Format Data Name Units |
| |
| 1- 11 A11 MCG number |
| 12 1X Blank |
| 13- 18 A6 NGC/IC number |
| 19 1X Blank |
| 20 A1 Add. info. flag |
| 21- 23 I3 RA hours |
| 24- 26 I3 minutes |
| 27- 29 I3 seconds |
| 30- 33 I4 Dec. degrees |
| 34- 36 I3 arcminutes |
| 37- 42 F6.2 Integrated magnitude magnitudes |
| 43- 44 I2 Mag. accuracy code |
| 45- 48 I4 Mag. reference |
| 49 1X Blank |
| 50 A1 Combined mag. flag |
| 51 I1 Number of gal. in mag. |
| 52- 57 F6.2 Major axis, inner part arcminutes |
| 58- 63 F6.2 Minor axis, inner part arcminutes |
| 64- 65 I2 Surface brightness |
| 66- 71 F6.2 Major axis, whole arcminutes |
| 72- 77 F6.2 Minor axis, whole arcminutes |
| 78 1X Blank |
| 79 A1 Diameter uncertainty flag |
| 80 1X Blank |
| 81 I1 Surf. brt., outer region 1 |
| 82 I1 Surf. brt., outer region 2 |
| 83- 84 I2 Inclination |
| 85- 90 F6.2 Major axis, POSS blue arcminutes |
| 91- 96 F6.2 Minor axis, POSS blue arcminutes |
| 97-102 F6.2 Major axis, POSS red arcminutes |
| 103-108 F6.2 Minor axis, POSS red arcminutes |
| 109-110 I2 Diameter uncertainty |
| 111-114 I4 Position angle degrees |
| 115-116 I2 Pos. angle uncertainty |
| 117 1X Blank |
| |
| |
| Figure 2. Catalog Record Format (1 of 4) |
+---------------------------------------------------------------------------+
Structure 4
MCG NUMBER Identification number from the "Morphological Cata-
logue of Galaxies" [bytes 1-11, format A11]
NGC/IC NUMBER The first character in this field indicates the cat-
alog:
N NGC catalog
I IC catalog
A Anonymous galaxy from the RC1 catalog
The next four characters contain the object number.
This field is blank if the galaxy does not appear in
any of these catalogs. [bytes 13-18, format A6]
ADD. INFO. FLAG "If * , then additional information is given, oth-
erwise blank." [byte 20, format A1]
EQUATORIAL COORDINATES Epoch 1950.0
RA HOURS [bytes 21-23, format I3]
RA MINUTES [bytes 24-26, format I3]
RA SECONDS [bytes 27-29, format I3]
DEC DEGREES [bytes 30-33, format I4]
DEC ARCMINUTES [bytes 34-36, format I3]
INTEGRATED MAGNITUDE [bytes 37-42, format F6.2]
MAG. ACCURACY CODE Accuracy of the magnitude as reported in the source
catalog, coded as a single digit:
1 Accurate to 0.01 magnitude
2 Accurate to 0.1 magnitude
3 Accurate to 1 magnitude
[byte 43-44, format I2]
MAG. REFERENCE Three-digit code number of the source reference for
the magnitude [bytes 45-48, format I4]
COMBINED MAG. FLAG "Z" if the magnitude given is that of two or more
galaxies, otherwise blank [byte 50, format A1]
NUMBER OF GAL. IN MAG. Number of galaxies included in the combined magni-
tude [byte 51, format I1]
Structure 5
MAJOR AXIS, INNER PART Angular diameter along the major axis of the bright
inner part of the galaxy, in arcminutes, as given in
the MCG. [bytes 52-57, format F6.2]
MAJOR AXIS, INNER PART; MINOR AXIS, INNER PART; MA-
JOR AXIS, WHOLE; and MINOR AXIS, WHOLE are all accu-
rate to 0.1 arcminutes, in general, and to 0.05
arcminutes in some cases. A "0" in the final deci-
mal place does NOT imply greater accuracy.
MINOR AXIS, INNER PART Angular diameter along the minor axis of the bright
inner part of the galaxy, in arcminutes, as given in
the MCG (see the note under MAJOR AXIS, INNER PART)
[bytes 58-63, format F6.2]
SURFACE BRIGHTNESS Surface brightness of the inner part of the galaxy
as listed in the MCG. This value is on a scale of
1-6, 1 being completely black and 6 barely visible.
[bytes 64-65, format I2]
MAJOR AXIS, WHOLE Angular diameter across the major axis of the entire
galaxy as reported in the MCG, in arcminutes (see
the note under MAJOR AXIS, INNER PART) [bytes 66-71,
format F6.2]
MINOR AXIS, WHOLE Angular diameter across the minor axis of the entire
galaxy as reported in the MCG, in arcminutes (see
the note under MAJOR AXIS, INNER PART) [bytes 72-77,
format F6.2]
DIAM. UNCERTAINTY FLAG ">" if the diameters in bytes 67-71 and 72-77 are
lower limits, otherwise blank [byte 79, format A1]
SURF. BRT., OUTER REG. 1 Surface brightness of the first outer region of the
galaxy, on the MCG scale described from SURFACE
BRIGHTNESS, above [byte 81, format I1]
SURF. BRT., OUTER REG. 2 Surface brightness of the second outer region of the
galaxy, on the MCG scale described from SURFACE
BRIGHTNESS, above [byte 82, format I1]
INCLINATION Estimated inclination of the principal plane to the
line of sight, as stated in the MCG. The numbers
1-5 used in the computer-readable MERCG correspond
to the Roman numerals I-V of the MCG. On this scale
I(1) is face on, V(5) is edge on. [byte 83-84, for-
mat I2]
MAJOR AXIS, POSS BLUE Angular diameter along the major axis measured on
the blue prints of the Palomar Observatory Sky Sur-
vey (POSS) from the UGC, in arcminutes [bytes 85-90,
format F6.2]
Structure 6
MINOR AXIS, POSS BLUE Angular diameter along the minor axis measured on
the blue prints of the POSS from the UGC, in
arcminutes [bytes 91-96, format F6.2]
MAJOR AXIS, POSS RED Angular diameter along the major axis measured on
the red prints of the POSS from the UGC, in
arcminutes [bytes 97-102, format F6.2]
MINOR AXIS, POSS RED Angular diameter along the minor axis measured on
the red prints of the POSS from the UGC, in
arcminutes [bytes 103-108, format F6.2]
DIAMETER UNCERTAINTY A single-digit integer indicating the uncertainty in
the diameters obtained from the POSS prints:
0 All values are certain
1 Blue POSS print values are uncertain
2 Red POSS print values are uncertain
3 Both blue and red POSS print values are uncer-
tain
[bytes 109-110, format I2]
POSITION ANGLE Position angle from the UGC, in degrees [bytes
111-114, format I4]
POS. ANGLE UNCERTAINTY A single-digit integer indicating the uncertainty in
the position angle, as indicated in the UGC:
0 Position angle is certain
1 Position angle is uncertain
2 Face-on spiral (indicated in the UGC by paren-
theses)
3 Assymetric system (indicated in UGC by square
brackets)
[bytes 115-116, format I2]
2.2.2 STRUCTURAL DETAILS
_________________________
Structure 7
+---------------------------------------------------------------------------+
| |
| Bytes FORTRAN Format Data Name |
| |
| 118 A1 General appearance |
| 119 A1 Structure detail 1 |
| 120 A1 Structure detail 2 |
| 121 A1 Faint gal./sup. star |
| 122 A1 Galaxy/star detail |
| 123-124 I2 Number of nuclei |
| 125 A1 Inner region detail |
| 126 A1 Nuclear region detail 1 |
| 127 A1 Nuclear region detail 2 |
| 128 1X Blank |
| 129 A1 Sep. symbol 1 |
| 130 A1 No. of details 1 |
| 131 A1 Gen. desc. 1 |
| 132 A1 Structure detail 1a |
| 133 A1 Structure detail 1b |
| 134 A1 Structure detail 1c |
| 135 A1 Uncertainty flag 1 |
| 136 1X Blank |
| 137 A1 Sep. symbol 2 |
| 138 A1 No. of details 2 |
| 139 A1 Gen. desc. 2 |
| 140 A1 Structure detail 2a |
| 141 A1 Structure detail 2b |
| 142 A1 Structure detail 2c |
| 143 A1 Uncertainty flag 2 |
| 144 1X Blank |
| 145 A1 Sep. symbol 3 |
| 146 A1 No. of details 3 |
| 147 A1 Gen. desc. 3 |
| 148 A1 Structure detail 3a |
| 149 A1 Structure detail 3b |
| 150 A1 Structure detail 3c |
| 151 A1 Uncertainty flag 3 |
| 152 1X Blank |
| 153 A1 Sep. symbol 4 |
| 154 A1 No. of details 4 |
| 155 A1 Gen. desc. 4 |
| 156 A1 Structure detail 4a |
| 157 A1 Structure detail 4b |
| 158 A1 Structure detail 4c |
| 159 A1 Uncertainty flag 4 |
| 160 1X Blank |
| 161 A1 Sep. symbol 5 |
| 162 A1 No. of details 5 |
| 163 A1 Gen. desc. 5 |
| 164 A1 Structure detail 5a |
| 165 A1 Structure detail 5b |
| 166 A1 Structure detail 5c |
| 167 A1 Uncertainty flag 5 |
| 168 1X Blank |
| |
| Figure 3. Catalog Record Format (2 of 4) |
+---------------------------------------------------------------------------+
Structure 8
Bytes 118-122 are a coded description of the overall appearance of the gal-
axy, in the system of the MCG. Descriptions of the MCG codes from the intro-
duction to that catalog are included in this document in Appendix B, "MCG
Symbols."
GENERAL APPEARANCE Single-letter code describing the general appearance
of the galaxy [byte 118, format A1]
STRUCTURE DETAILS Two single-character codes, each describing a struc-
tural detail. The code used in the computer-
readable MERCG is listed below, with the
corresponding MCG code to the right.
A a 9 ->L Z z T t
5 ad 2 o 7 bi 6 ai
W w M m 8 n 4 ?
I i D d C c B b
E e F f P p 1 A
[bytes 119 and 120, both format A1]
FAINT GAL./SUP. STAR Description (as in byte 118) of the faint galaxy
seen in contact with the principal one, or "*" if a
star is projected onto the image of the galaxy [byte
121, format A1]
GALAXY/STAR DETAIL Structure of the faint galaxy (as in bytes 119 and
120), or inclination of the galaxy to the line of
sight (as in bytes 83-84). If a superimposed star
is indicated in byte 121, then this field contains a
single-digit code indicating where the star image
appears:
1 The star is projected onto the nuclear region of
the galaxy.
2 The star is projected onto the outer region of
the galaxy.
3 The star is "close-by" the galaxy.
4 The star may be projected onto the galaxy.
[byte 122, format A1]
Bytes 123-127 are a coded description of the bright inner region of the gal-
axy, as listed in the MCG.
NUMBER OF NUCLEI Number of galactic nuclei seen in contact [byte
123-124, format I2]
Structure 9
INNER REGION DETAIL Character code describing the inner region of the
galaxy. The codes "N", "L", and "$" correspond to
the MCG codes "N", "L", and "n", respectively.
[byte 125, format A1]
NUCLEAR REGION DETAIL Two single-character codes describing the structural
detail of the nucleus. The codes used are the same
as those described above for the overall appearance
under STRUCTURE DETAILS, with the addition of "3" to
represent the MCG symbol "()". [bytes 126 and 127,
both format A1]
OUTER PART Symbolic description of the appearance of the outer
part of the galaxy from the MCG, broken down into as
many as five different areas extending outward from
the nucleus. The descriptions for all five areas
are in the same format:
SEP. SYMBOL Character used to separate symbols
describing this area from those of
the other areas. The characters "1"
and "2" in the computer-readable file
represent the MCG symbols ";;" and
"->", respectively (the meanings of
these symbols are described in Appen-
dix B: "MCG Symbols"). [bytes 129,
137, 145, 153, and 161, all format
A1]
NO. OF DETAILS Number of structural details de-
scribed by the GENERAL DESCRIPTION
following. When this field contains
9, it "must be considered as a dupli-
cation of symbols" in the GENERAL DE-
SCRIPTION. [bytes 130, 138, 146,
154, and 162, all format A1]
GEN. DESC. General description of the external
areas of the galaxy. Each symbol
used in the computer-readable MERCG
is listed below with the correspond-
ing MCG symbol to the right. The
symbols in parentheses actually come
from the cryllic alphabet and resem-
ble backwards "S", "s", and/or "c"
characters. Therefore "(s)" repres-
ents a small backwards "s", and (s)+s
represents a small backwards "s" con-
catenated with the characters "+s"
See the original hardcopy documenta-
tion for the actual text symbols.
Structure 10
The meaning of these symbols are de-
scribed in Appendix B, "MCG Symbols."
S S T T
C C L L
H H 6 GAM
4 Sss @ r
B B R R
D D 2 s
9 l 5 (S)+S
3 (Sss) # (S)
1 (s) 8 (cc)
0 (s)+s
[bytes 131, 139, 147, 155, and 163,
all format A1]
STRUCT. DET. Three single-character codes detail-
ing the structure of the area, using
the same symbols as in bytes 119 and
120, with the following additional
codes:
K Galaxy with sharp edges
X Traces of structure
Q Uncertainty in the number of arms
[bytes 132-134, 140-142, 148-150,
156-158, and 164-166, all format A1,
A1, A1]
UNCERTAINTY FLAG Single-character code indicating
uncertainty in structure details.
The codes used in the computer-
readable version and their MCG equiv-
alents are listed below.
1 '
2 -
4 "structure uncertainty"
3 ( )
6 "structure incompleteness"
8 ->8
R ->R
[bytes 135, 143, 151, 159, and 167,
all format A1]
Structure 11
2.2.3 CLASSIFICATIONS, VELOCITIES, AND SPECTRAL DETAILS
________________________________________________________
+---------------------------------------------------------------------------+
| |
| Bytes FORTRAN Format Data Name Units |
| |
| 169 A1 Source of rev. Hubble class. |
| 170 1X Blank |
| 171 A1 Outer ring (rev. Hubble) |
| 172-175 A4 Type (rev. Hubble) |
| 176-177 A2 Peculiarities (rev. Hubble) |
| 178 1X Blank |
| 179-181 A3 Type (Morgan) |
| 182-183 A2 Spectral class (Morgan) |
| 184 A1 Peculiarities (Morgan) |
| 185 1X Blank |
| 186-193 A8 Hubble/van den Bergh class. |
| 194 1X Blank |
| 195 A1 Source of H/vdB class. |
| 196-202 I7 Heliocentric rad. vel. km/sec |
| 203-206 I4 Hel. rad. vel. reference |
| 207-213 I7 Corrected rad. vel. km/sec |
| 214-217 I4 Corr. rad. vel reference |
| 218-221 I4 Rotational velocity km/sec |
| 222-227 F6.2 r(H) (see below) |
| 228 1X Blank |
| 229 A1 r(H) uncertainty |
| 230-233 I4 Rot. vel. reference |
| 234-236 I3 First supernova date |
| 237-239 I3 Second supernova date |
| 240-241 I2 Number of supernovae |
| 242-245 I4 Number of H II regions |
| 246-249 I4 H II region reference |
| 250-255 F6.2 Integrated U-B magnitudes |
| 256-259 I4 U-B reference |
| 260-264 F5.2 Integrated B-V magnitudes |
| 265-268 I4 B-V reference |
| 269-274 F6.2 Face-on U-B magnitudes |
| 275-279 F5.2 Face-on B-V magnitudes |
| 280 1X Blank |
| 281-282 A2 Integral spectrum |
| 283-287 F5.1 Flux density, 178 MHz janskys |
| 288-291 I4 Reference, 178 MHz |
| 292-296 F5.1 Flux density, 780 MHz janskys |
| 297-300 I4 Reference, 780 MHz |
| 301-305 F5.2 Flux density, 1400 MHz janskys |
| 306-309 I4 Reference, 1400 MHz |
| 310-314 F5.2 Flux density, 2700 MHz janskys |
| 315-318 I4 Reference, 2700 MHz |
| 319-323 F5.2 Flux density, 5000 MHz janskys |
| 324-327 I4 Reference, 5000 MHz |
| |
| |
| Figure 4. Catalog Record Format (3 of 4) |
+---------------------------------------------------------------------------+
Structure 12
Bytes 169-177 describe the de Vaucouleurs classification of the galaxy, as
found in the source indicated in byte 169.
SOURCE OF REV. HUBBLE CLASS. Single-character code indicating the source of
the revised Hubble (de Vaucouleurs) classification.
Only two codes are used:
U UGC
R RC1
[byte 169, format A1]
OUTER RING [byte 171, format A1]
TYPE [bytes 172-175, format A4]
PECULIARITIES [bytes 176-177, format A2]
Bytes 179-181 describe the type of the galaxy according to Morgan s classi-
fication scheme, as listed in the RC1 and RC2.
TYPE [bytes 179-181, format A3]
SPECTRAL CLASS [bytes 182-183, format A2]
PECULIARITIES [byte 184, format A1]
Bytes 186-193 describe either the Hubble classification of this galaxy from
the UGC or the van den Bergh classification from the RC1. Byte 195 indicates
which of these two classifications is listed here.
If the Hubble classification is present, this field breaks down as follows:
GALAXY TYPE Each code used in the computer-readable MERCG is
listed below with the corresponding UGC code to the
right:
E E 3 Dwarf I
SB SB SO SO
1 Dwarf I I
5 Dwarf P 4 Dwarf E
E0 E0 SR S(R)
S1 SBO S2 SB(r)
2 Dwarf S S3 SBO(R)
S S S4 S(R)O
P P
[bytes 186-187, format A2]
Structure 13
STRUCTURE DETAILS The computer-readable MERCG codes and the corre-
sponding UGC symbols are listed below:
A a 1 a-b
B b 2 b-c
C c 3 cd
D d
[byte 188, format A1]
ADDITIONAL SYMBOLS These characters include special symbols used to
modify the characteristics indicated. The UGC sym-
bol appears to the right:
: : 1 ? / / 2 [] 3 -
[byte 189, format A1]
GALAXY TYPE, CONTINUED Continuation of the type started in bytes 186-187
using the same codes [bytes 190-191, format A2]
STRUCT. DET., CONT D The same codes are used here as for byte 188.
[bytes 192, format A1]
LUMINOSITY CLASS [byte 193, format A1]
For the van den Bergh classification, the format differs:
TYPE [bytes 186-187, format A2]
STRUCTURE DETAILS [byte 188, format A1]
PECULIARITIES Or additional symbols [byte 189, format A1]
SPIRAL ARMS Characteristics of the spiral arms [bytes 190-192,
format A3]
LUMINOSITY CLASS [byte 193, format A1]
SOURCE OF CLASS. Source of the classification described in bytes
186-193 [byte 195, format A1]
HELIOCENTRIC RAD. VEL. Heliocentric radial velocity in km/sec [bytes
196-202, format I7]
HEL. RAD. VEL. REF. Source reference number for the heliocentric radial
velocity in bytes 196-202 [bytes 203-206, format I4]
Structure 14
CORRECTED RAD. VEL. Radial velocity corrected for the solar motion, in
km/sec [bytes 207-213, format I7]
CORR. RAD. VEL. REF. Source reference number for the corrected velocity
in bytes 207-213 [bytes 214-217, format I4]
ROTATIONAL VELOCITY km/sec/kpc [bytes 218-221, format I4]
R(H) On the rotation curve, the distance from the center
to the bending point. If the reference cited in
bytes 231-233 is reference 11, this is in units of
arcminutes. If reference 12 is cited, this is in
kpc. [bytes 222-227, format F6.2]
R(H) UNCERTAINTY ">" if the value in bytes 223-227 represents a lower
limit. Otherwise, this field is blank. [byte 229,
format A1]
ROT. VEL. REFERENCE Rotational velocity reference code number; either
11, 12, or blank [bytes 230-233, format I4]
FIRST SUPERNOVA DATE Last two digits of the year in which the first
supernova was observed in this galaxy [bytes
234-236, format I3]
SECOND SUPERNOVA DATE Last two digits of the year in which the second
supernova was observed [bytes 237-239, format I3]
NUMBER OF SUPERNOVAE Total number of supernovae observed in this galaxy
[bytes 240-241, format I2]
NUMBER OF H II REGIONS [bytes 242-245, format I4]
H II REGION REFERENCE Code number of the reference for the HII regions of
bytes 242-245 [bytes 246-249, format I4]
INTEGRATED U-B Integrated U-B color, in magnitudes [bytes 250-255,
format F6.2]
U-B REFERENCE Coded reference to the color in bytes 250-255 [bytes
256-259, format I4]
INTEGRATED B-V Integrated B-V color, in magnitudes [bytes 260-264,
format F5.2]
B-V REFERENCE Coded reference to the color in bytes 260-264 [bytes
265-268, format I4]
FACE-ON U-B "Integrated face-on (U-B)o color" from the RC1 or
RC2, in magnitudes [bytes 269-274, format F6.2]
FACE-ON B-V "Integrated face-on (B-V)o color" from the RC1 or
RC2, in magnitudes [bytes 275-279, format F5.2]
Structure 15
INTEGRAL SPECTRUM [bytes 281-282, format A2]
FLUX DENSITY, 178 MHZ Radio flux density observed at 178 MHZ, in janskys
[bytes 283-287, format F5.1]
REFERENCE, 178 MHZ Coded reference to the flux density at 178 MHz
[bytes 288-291, format I4]
FLUX DENSITY, 780 MHZ Radio flux density observed at 780 MHz, in janskys
[bytes 292-296, format F5.1]
REFERENCE, 780 MHZ Coded reference to the flux density at 780 MHz
[bytes 297-300, format I4]
FLUX DENSITY, 1400 MHZ Radio flux density observed at 1400 MHz, in janskys
[bytes 301-305, format F5.2]
REFERENCE, 1400 MHZ Coded reference to the flux density at 1400 MHz
[bytes 306-309, format I4]
FLUX DENSITY, 2700 MHZ Radio flux density observed at 2700 MHz, in janskys
[bytes 310-314, format F5.2]
REFERENCE, 2700 MHZ Coded reference to the flux density at 2700 MHz
[bytes 315-318, format I4]
FLUX DENSITY, 5000 MHZ Radio flux density observed at 5000 MHz, in janskys
[bytes 319-323, format F5.2]
REFERENCE, 5000 MHZ Coded reference to the flux density at 5000 MHz
[bytes 324-327, format I4]
Structure 16
2.2.4 MULTIPLE SYSTEM AND INTERACTION DETAILS
______________________________________________
+---------------------------------------------------------------------------+
| |
| Bytes FORTRAN Format Data Name Units |
| |
| 328-331 I4 Nearby cluster number |
| 332 1X Blank |
| 333 A1 CCG flag |
| 334 1X Blank |
| 335 A1 Markarian list flag |
| 336 1X Blank |
| 337 A1 Isolated galaxy flag |
| 338 1X Blank |
| 339 A1 Isolated pair flag |
| 340 1X Blank |
| 341 A1 Byurakan nuclear type |
| 342 1X Blank |
| 343 A1 Emission line flag |
| 344-345 I2 Companion code |
| 346 1X Blank |
| 347 A1 Multiple mem. designation |
| 348-351 I4 Comp. MCG number |
| 352-353 I2 Degree of isolation |
| 354-355 I2 Number interacting |
| 356 1X Blank |
| 357 A1 Interaction flag |
| 358-359 I2 Interaction type |
| 360-361 I2 Distortion type |
| 362-365 F4.1 Ang. separation arcminutes |
| 366-367 I2 Number of faint comp. |
| 368-369 I2 Component code |
| 370-372 I3 MCG number/magnitude |
| 373-376 F4.1 Ang. distance arcminutes |
| |
| |
| |
| Figure 5. Catalog Record Format (4 of 4) |
+---------------------------------------------------------------------------+
NEAR-BY CLUSTER NUMBER Near-by cluster number in the CGCG, as taken from
the UGC, if the galaxy is within the outline of the
indicated cluster [bytes 328-331, format I4]
CCG FLAG "1" if this galaxy is listed in the CCG, otherwise
blank [byte 333, format A1]
MARKARIAN LIST FLAG "1" if this galaxy is contained in Markarian s lists
of galaxies, otherwise blank [byte 335, format A1]
Structure 17
ISOLATED GALAXY FLAG "1" if this galaxy is in the "Catalogue of Isolated
Galaxies", otherwise blank [byte 337, format A1]
ISOLATED PAIR FLAG "1" if this galaxy is in the "Catalogue of Isolated
Pairs of Galaxies", otherwise blank [byte 339, for-
mat A1]
BYURAKAN NUCLEAR TYPE Byurakan classification of the galactic nucleus (see
reference number 50) [byte 341, format A1]
EMISSION LINE FLAG "1" if reference number 54 indicates that the spec-
trum contains emission lines [byte 343, format A1]
Bytes 344-353 contain coded information on the membership of this galaxy in
a double or multiple system.
COMPANION CODE Single-digit number indicating the presence of a
companion galaxy, with or without an MCG number. If
there is no companion, this field is blank. The
following codes are used:
1 The companion has an MCG number.
2 The companion has no MCG number.
3 More than one galaxy is described by a single
MCG number.
[byte 344-345, format I2]
MULT. MEM. DESIGNATION Single-character code giving information about this
galaxy s membership in a multiple system:
1 Brightest member of a multiple system
K One of the fainter members of a multiple system
2 Member of a binary system
D Another member of a binary system
3 Brightest member of a ternary system
T One of the fainter members of a ternary system
[byte 347, format A1]
COMP. MCG NUMBER MCG number of the component (in the same field) in-
dicated by "1" in byte 345, otherwise blank [bytes
348-351, format I4]
Structure 18
DEGREE OF ISOLATION Degree of isolation of a pair of galaxies, as indi-
cated in reference 57. The integer codes used and
the reference 57 equivalents are listed below.
1 + , +
2 - , -
3 + , -
4 - , +
[bytes 352-353, format I2]
Bytes 354-365 contain coded information of the existence and type of inter-
action features.
NUMBER INTERACTING Integer number of members observed to be interacting
[byte 354-355, format I2]
INTERACTION FLAG Single-character code indicating the certainty of
interaction:
B Evident interaction
Q Suspected interaction
[byte 357, format A1]
INTERACTION TYPE Single-digit integer code indicating the type of
interaction observed:
1 Galaxies connected by a bar
2 Galaxies connected by a spiral arm
3 Galaxies in contact
4 Galactic nuclei in contact
5 Nest of galaxies
6 Chain of galaxies
7 Galaxies embedded in a common nebulous envelope
8 Interaction at a distance
9 Blended galaxies
[byte 358-359, format I2]
Structure 19
DISTORTION TYPE Single-digit integer code indicating the type of
distortion (if any) of the galaxy s form:
1 Tail
2 Unusual branched feature, e.g., a jet, streamer,
or plume
3 Halo
4 Clear evidence of structure distortion
7 Galaxies embedded in a common nebulous envelope
[byte 360-361, format I2]
ANG. SEPARATION Angular separation, in arcminutes [bytes 362-365,
format F4.1]
Bytes 366-376 contain coded information about the existence of faint compo-
nents.
NUMBER OF FAINT COMP. Number of faint components in the multiple system
[byte 366-367, format I2]
COMPONENT CODE Single-digit integer indicating the type of compo-
nent:
1 Faint component with an MCG number
2 Faint component without an MCG number
3 Nearby faint galaxy
4 Questionable object (a star or a defect) near
the galaxy
[bytes 368-369, format I2]
MCG NUMBER/MAGNITUDE Two-digit integer containing either the MCG number
of the component, if byte 369 contains "1", other-
wise the magnitude of the nearest component [bytes
370-372, format I3]
ANG. DISTANCE Angular distance to the nearest companion, in
arcminutes [bytes 373-376, format F4.1]
Structure 20
2.3 REFERENCES (FILE 2 OF 2)
_____________________________
This file lists the full forms of the 253 references cited by number in the
main catalog file.
+---------------------------------------------------------------------------+
| |
| Bytes FORTRAN Format Data Name |
| |
| 1- 3 I3 Reference number |
| 4-65 A62 Reference text |
| 66-80 A15 Reference subject |
| |
| |
| Figure 6. Reference Record Format |
+---------------------------------------------------------------------------+
REFERENCE NUMBER Code number by which the reference is cited in the
data file [bytes 1-3, format I3]
REFERENCE TEXT The full form of the reference. When necessary, ad-
ditional records are used to contain the full text.
Continuation records are distinguished by having
blanks in bytes 1-3. [bytes 4-65, format A62]
REFERENCE SUBJECT Brief description of the subject of the reference.
When necessary this field also continues into the
next record. [bytes 66-80, format A15]
Structure 21
3.0 HISTORY
____________
3.1 REMARKS AND MODIFICATIONS
______________________________
"Merged Catalogue of Galaxies" (MERCG) was received by the Astronomical Data
Center (ADC), NASA Goddard Space Flight Center, from the Centre de Donnees
Astronomiques, Strasbourg (CDS), in December 1986. The tape contained four
files: one of catalog data, one of references, one of remarks, and one of
notes. The last two files have been incorporated into this document in their
entirety. An editor was used to delete the character "*" from the code num-
ber field of continuation records in the reference file, and to perform minor
reformatting of some records in order to preserve the format described in
"References (File 2 of 2)."
A FORTRAN program was run to check the validity of each field according to
its data type and value. A number of typographical errors were discovered in
the data file. N. Kogoshvili was contacted by letter and kindly supplied the
necessary corrections. All changes made to the catalog file are listed in
Appendix A, "Corrections to the Computer-Readable Version."
3.2 REFERENCES TO THE DOCUMENTATION
____________________________________
Kogoshvili, N. 1986, unpublished documentation distributed with the cata-
log by the Centre de Donnees Stellaires.
Kogoshvili, N. 1987, private communication.
Vorontsov-Velyaminov, B. A., Krasnogorskaja, A., and Arkhipova, V. P.
1962-68, "Morphological Catalogue of Galaxies" (6 volumes; Moscow).
History 22
APPENDIX A. CORRECTIONS TO THE COMPUTER-READABLE VERSION
________________________________________________________
As mentioned in "History," a FORTRAN program run on the MERCG to check the
validity of each field revealed a number of typographical errors in the cata-
log file. N. Kogoshvili kindly supplied the necessary corrections which have
been made to the data. Following is a list of all records affected and the
changes made.
+------------+-------+------------------------------------------------------+
| | | |
| | | |
| MERCG |Record | Correction |
| Number |Number | |
| | | |
| | | |
+------------+-------+------------------------------------------------------+
|+09-12-001 |3998 |"." in bytes 125, 132, 138, and 139 and an |
| | |unrecognizable character in byte 118 were all changed |
| | |to blanks. |
+------------+-------+------------------------------------------------------+
|+09-12-003 |4000 |"." in bytes 118 and 139 was replaced by a blank. |
+------------+-------+------------------------------------------------------+
|+07-32-019 |9306 |The symbol "L" in byte 162 was shifted right one byte |
| | |to the blank byte 163. Byte 162 was filled with a |
| | |blank. This was done to enable the field in byte 162 |
| | |to be read with a FORTRAN I1 format, as in all other |
| | |records. |
+------------+-------+------------------------------------------------------+
|+04-27-051 |5439 |The value "1" in byte 355 was changed to "2". |
+------------+-------+------------------------------------------------------+
|-01-08-026 |5522 |The value "7" in byte 82 was changed to "6". |
+------------+-------+------------------------------------------------------+
|-02-33-089 |7733 |An unrecognizable character in byte 131 was changed |
| | |to "D". |
+------------+-------+------------------------------------------------------+
|-02-35-004 |7816 |"." in byte 190 was changed to a blank. |
+------------+-------+------------------------------------------------------+
|-02-35-005 |7817 |"." in byte 145 was changed to a blank. |
+------------+-------+------------------------------------------------------+
|-05-04-028 |0889 |An erroneous declination of -37 degrees was corrected |
| | |to -27 degrees, the value listed in the MCG. |
+------------+-------+------------------------------------------------------+
|-05-26-006 |1291 |An erroneous declination of -38 degrees was corrected |
| | |to -28 degrees, the value listed in the MCG. |
+------------+-------+------------------------------------------------------+
Appendix A. Corrections to the Computer-Readable Version 23
APPENDIX B. MCG SYMBOLS
_______________________
Following is a description of the various codes used in the MCG to detail the
structure and appearance of galaxies in that catalog. This information has
been taken from the English introduction to the "Morphological Catalogue of
Galaxies. Part I." (Vorontsov-Velyaminov and Krasnogorskaja 1962).
Quotes in this section are from Vorontsov-Velyaminov and and Krasnogorskaja
1962).
Some of the symbols dscribed here can not be represented in computer-readable
form. These symbols include the following: the greek letter gamma, which
will be represented by "GAM"; an arrow pointing towards the right, which will
be represented by "->"; and several letters from the cryllic alphabet. The
cryllic letters resemble the letters "S", "s", and "c" but facing backwards
instead. They are represented in the following text by enclosing them in pa-
rentheses. Please refer to the original hardcopy documentation for the MERCG
for the actual text symbols.
The galaxies are divided into four general groups:
E Elliptical galaxy
F Flattened galaxy (in general this indicates a highly inclined galaxy
with no discernable form)
Fs Flattened galaxy in which is also seen the end of a spiral arm
G Small galaxy, difficult to describe
Following this general breakdown is a description of the galaxy in terms of
zones extending outward from the nucleus. Individual details of structure
are separated by special symbols which also serve to indicate the general re-
lationship between structural details:
, Separates details of the same zone
; Separates details of different zones
;; "Indicates that the outer details are completely detached from the inner
ones"
-> Indicates that the preceding detail tends to blend into the next
Appendix B. MCG Symbols 24
The following codes are used to indicate the presence of various structural
details. They are listed roughly in order from the nucleus outward.
N Large nucleus
n Small nucleus
e Following "N" or "n", indicates elongation of the nucleus
(N) "Overexposed image with traces of structure" resembling "N"
Subscript n With "N" or "n", indicates nebulosity of the nucleus
H Halo or haze
Hp "Very assymetrical or disturbed haze"
D Disk
D- Incomplete disk
L Lens
Vorontsov-Velyaminov and Krasnogorskaja note that "no sharp
boundary exists between faint H and D , D and L , [or]
bright L and N ."
R Single ring
RR Several rings
R- Incomplete ring
D->R The disk becomes brighter at the rim, producing a ring effect.
B Short bar with no nucleus
B- Very short bar
BB Long bar
BBB Very long bar
2B Bar seen on both sides of an "N" or "L" galaxy
"N; 2B" indicates the bar is relatively faint. "N, 2B" indi-
cates the bar and nucleus are of comparable brightness.
S or (S) Indicate long spiral arms opening in a clockwise or counter-
clockwise direction, respectively. These symbols are preceded
by the number of arms observed; for example, two arms opening
clockwise would be represented by "2S".
s or (s) Indicate short spiral arms
Appendix B. MCG Symbols 25
SS or (SS) Indefinite number of spiral arms
SS or (SS) Spiral arms with an indefinite direction of winding
S The arms wind in opposite directions.
Sss Branching spiral arms
(c) Single arc
(cc) Several arcs
r Ray
GAM Spiral arms that emerge in a manner resembling the greek let-
ter gamma
GAM->R Indicates that the gamma arms tend to form a ring
2S->8 Spiral arms extending back into the nucleus to form a figure
eight
S->R Spiral arm transforms into a ring
(N), SS or (F); ss Indicates that the ends of a flat system are visible
D, (2S) Spiral arms suspected in a "D" galaxy
L, (2s) Spiral arms suspected in an "L" galaxy
2l The galaxy has two wings ("It must be the flattened component
seen nearly edgewise.")
P Indefinite patch
A Absorption features
T Tail
C Connecting filament between interacting galaxies
+ * Superimposed star on the image of the galaxy
The symbols of the next group are used to qualify those previously listed:
m Massive
f Filamentary
w Wide
t Tight arms
Appendix B. MCG Symbols 26
o Open arms
z Arms starting at right angles to a bar
->8 Transition to figure eight or loop
Additionally, the degree of patchiness or resolution of a particular detail
is indicated by the codes "a", "b", "c", "d", and "i". The letters "a-d"
represent decreasing patchiness, with "a" being smooth and "d" very patchy.
The letter "i" indicates irregularity. Combinations of these such as "ab" or
"bc" used to represent intermediate steps in the progression in the MCG have
been shortened to the one letter representing the greater degree of
patchiness. Kogoshvili (1987) notes that this was done by agreement with B.
A. Vorontsov-Velyaminov, for technical reasons.
The code "p" (distinct from "P") denotes deformity in a specific detail and
NOT peculiarity in general.
Repetition of lower-case letters and "!" are used to accentuate the corre-
sponding quality. A symbol in parentheses indicates that the detail is only
suspected.
In the introduction to Part III of the MCG, Vorontsov-Velyaminov and Arhipova
note two changes made to the above system:
The symbol "(SSS)" is introduced to indicate numerous indefinite spiral
arms while "(SS)" is reserved for a small number of indefinite arms.
This distinction has NOT been carried over into the MERCG.
Details that are generally smooth but with bright condensations that
would otherwise cause the detail to be classified as "d" or "i" are now
described by a combination of symbols, such as "ai", "ad", or "bi".
Finally, Vorontsov-Velyaminov and Kranogorskaja note that:
The clear scheme of our description in practice is spoiled by the vague
appearance of many galaxies and by the multitude of transition cases.
Sometimes the same appearance can be described by different symbols of
adjacent meaning. For instance "N; 2la" can be the more detailed de-
scription of an "F" galaxy seen edge on. "D, (ss )" can be considered
a "Db" etc.
Appendix B. MCG Symbols 27
