The following document lists the file adc.doc
from catalogue VII/4A.
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SSD-T-1-0338-0098-83
DOCUMENTATI0N FOR THE MACHINE-READABLE VERSION OF THE
CATALOGUE OF ABELL AND ZWICKY CLUSTERS OF GALAXIES
(BULGARIAN ACADEMY OF SCIENCES)
April, 1983
Contract NAS 5-27393
Robert S. Hill
Prepared for:
National Aeronautics and Space Administration
Goddard Space Flight Center
Greenbelt, Maryland 20771
Prepared by:
Systems and Applied Sciences Corporation
6811 Kenilworth Avenue, Suite 500
Riverdale, Maryland 20737
SECTION 1 - INTRODUCTION
A COPY OF THIS DOCUMENT SHOULD ACCOMPANY EVERY DISTRIBUTED COPY OF THE
MACHINE-READABLE CATALOGUE.
This document describes a machine-readable version of the "Catalogue of Abell
and Zwicky Clusters of Galaxies" prepared by the Bulgarian Academy of Sciences.
This catalogue consists of three files, as follows:
File 1 - Abell Clusters (Abell 1958)
File 2 - Zwicky Clusters (Zwicky et al. 1961-68)
File 3 - Zwicky Plate Number Cross-Identifications (Zwicky et al.
1961-68)
Files 1 and 2 contain some calculated quantities as well as the data from the
published versions of the catalogues. File 3 connects the sequential numbering
of the Zwicky clusters in file 2 with Zwicky's own field and cluster numbers.
The Abell clusters are rich, compact clusters of galaxies identified by G. O.
Abell. From these he selected a statistical sample for inferences about the
distribution of galaxies in space. These clusters were identified on the red
plates of the Palomar Observatory Sky Survey (POSS).
The Zwicky clusters were identified by F. Zwicky in 560 POSS fields. They are
rich clusters, each having at least 50 members within 3 magnitudes of the
brightest member.
REFERENCES:
Abell, G. O. 1958, Astrophys. J. Suppl. 3, 211.
Corwin, H. G. 1974, Astron. J. 79, 1356.
Hill, R., Documentation for the Machine-Readable Version of the Catalogue of
Galaxies and of Clusters of Galaxies: Data on Individual Galaxies, SASC,
Document #SSD-T-1-5069-022-82.
Kalinkov, M., Stavrev, K. and Kaneva, I. 1975, Astron. Zh. (Letters) 1, no. 2,7.
de Vaucouleurs, G., de Vaucouleurs, A., Corwin, H. G. 1976, Second Reference
of Bright Galaxies (Austin, University of Texas).
Zwicky, F., Herzog, E., Wild, P., Karpowicz, M. and Kowal, C. T. 1961-68,
Catalogue of Galaxies and of Clusters of Galaxies (Pasadena, California
Institute of Technology, 6 vols.).
1-1
SECTION 2 - FILE CONTENTS
A byte-by-byte description of the contents of the catalogue is given in Tables
2-1, 2-2 and 2-3. The information in the "Description" column is derived mainly
from the published version of the catalogue whenever possible. The "Suggested
Format" column is for Fortran-formatted reads.
Table 2-1 File Contents (1 of 3): Abell Clusters
Bytes Description Suggested
Format
1 Blank 1X
2- 5 Abell cluster number (1...2712). The data in I4
the following fields are taken from the original
published catalogue: Abell cluster number (bytes
2-5), sample-cluster flag (byte 7), magnitude of
tenth-brightest member (bytes 25-28), distance
group (byte 31), and richness group (byte 34).
All other data are calculated.
6 Blank 1X
7 '2' if the cluster was included in Abell's stat- I1
istical sample, '1' if it was not.
8 Blank 1X
9-22 Equatorial coordinates (1950)
9-10 Hours of right ascension I2
11 Blank 1X
12-15 Minutes of right ascension F4.1
16 Blank 1X
17 Sign of declination A1
18-19 Degrees of declination I2
20 Blank 1X
21-22 Arc minutes of declination I2
23-24 Blank. 2X
25-28 Magnitude of the tenth brightest cluster F4.1
member. Measured on Palomar Observatory
Sky Survey (POSS) red (E) plates, by comparison
with calibrated galaxy images.
29-30 Blank. 2X
2-1
Table 2-1. File Contents (2 of 3): Abell Clusters
31 Distance group; based on the magnitude of the I1
tenth-brightest cluster member (bytes 25-28),
as follows:
Distance Group Magnitude Range
1 13.3-14.0
2 14.1-14.8
3 14.9-15.6
4 15.7-16.4
5 16.5-17.2
6 17.3-18.0
7 Over 18.0
The magnitude interval is approximately 3.5
times the standard error in magnitude estimate.
32-33 Blank. 2X
34 Richness group; the corresponding galaxy counts I1
are as follows:
Richness Group Counts
0 30-49
1 50-79
2 80-129
3 130-199
4 200-299
5 300 or over
The richness-group intervals are about 3 1/2
times the standard error in counts.
35-36 Blank. 2X
37-49 Galactic coordinates (system II).
37-42 Galactic longitude (degrees). F6.2
43 Blank. 1X
44-49 Galactic latitude (degrees). F6.2
50-51 Blank. 2X
52-74 Lambert coordinates. The Lambert
transformation is an equal-area projection.
52-58 Lambert distance RL from the F7.4
nearest galactic pole, defined by
RL = 2 sin ((90-b)/2)
RL > 0 in north galactic hemisphere
RL < 0 in south galactic hemisphere
59 Blank. 1X
60-66 X Lambert coordinate: F7.4
XL = 2 sin l sin ((90-b)/2)
Directed towards l = 90 deg for both
the north and the south galactic
hemispheres.
67 Blank. 1X
2-2
Table 2-1. File Contents (3 of 3): Abell Clusters
Suggested
Bytes Description Format
68-74 Y Lambert coordinate: F7.4
YL = 2 cos l sin ((90-b)/2)
Directed towards l = 0 deg for both
the north and the south galactic
hemispheres.
75-76 Blank. 2X
77-89 Supergalactic coordinates according to de
Vaucouleurs's new system (de Vaucouleurs et al.
1976, p. 8). (References follow Section 1
above.) The origin of longitude is at the
ascending node of the supergalactic equator
with the galactic equator. These coordinates
are calculated from the galactic coordinates.
77-82 Supergalactic longitude (degrees). F6.2
83 Blank. 1X
84-89 Supergalactic latitude (degrees). F6.2
90-91 Blank. 2X
92-95 Corrected Abell cluster radius in degrees, F4.2
assuming a Friedman cosmology with
deceleration parameter 1:
2
RAD = 0.02862 * (1 + z) / z
96-97 Blank. 2X
98-103 Cluster area in square degrees, computed from F6.3
bytes 92-95.
104-105 Blank. 2X
106-109 Mean apparent population, in galaxies per I4
square degree, which is a measure of the mean
surface density of cluster galaxies, defined as
population/area.
110-111 Blank. 2X
112-130 Distance to cluster in megaparsecs. Computed
for Hubble constant H = 100 km per second per
megaparsec.
112-114 Radial distance RH. I3
115-116 Blank. 2X
117-120 X component of RH: I4
XH = RH * cos b sin l
121 Blank. 1X
122-125 Y component of RH: I4
YH = RH * cos b cos l
126 Blank. 1X
127-130 Z component of RH: I4
ZH = RH * sin b
2-3
Table 2-2. File Contents (1 of 2): Zwicky Clusters
Suggested
Bytes Description Format
1 Blank 1X
2- 5 Cluster number (1...9134). This file is in I4
ascending order by right ascension (bytes 8-14),
whereas the original published catalogue is
sorted by the survey field number. File 3 of
this machine-readable version (see Table 2-3) is
a cross-index between the two systems.
The data in bytes 8-44 are from the original
published catalogue (Zwicky et al.); all other
data are calculated.
6- 7 Blank. 2X
8-22 Equatorial coordinates (1950).
8-9 Hours of right ascension. I2
10 Blank. 1X
11-14 Minutes of right ascension. F4.1
15-16 Blank. 2X
17 Sign of declination A1
18-19 Degrees of declination. I2
20 Blank. 1X
21-22 Arc minutes of declination. I2
23-25 Blank. 3X
26 Type: 1 for open, 2 for medium compact, or 3 I1
for compact cluster.
27-29 Blank. 3X
30-33 Population of cluster (number of galaxies). I4
34-36 Blank. 3X
37-40 Diameter of cluster (centimeters). F4.1
41-43 Blank. 3X
44 Distance group: 1 for near, 2 for medium I1
distant, 3 for distant, 4 for very distant, or 5
for extremely distant cluster.
45-47 Blank. 3X
2-4
Table 2-2. File Contents (2 of 2): Zwicky Clusters
Suggested
Bytes Description Format
48-61 Galactic coordinates (system II).
48-53 Galactic Longitude (degrees). F6.2
54-55 Blank. 2X
56-61 Galactic Latitude (degrees). F6.2
62-64 Blank. 3X
65-89 Lambert coordinates. The Lambert
tranformation is an equal-area projection. See
also Table 2-1, bytes 52-74.
65-71 Lambert distance RL from the F7.4
nearest galactic pole, defined by
RL = 2 sin ((90-b)/2)
RL> 0 for north galactic hemisphere
RL< 0 for south galactic hemisphere
72-73 Blank. 2X
74-80 X Lambert coordinate: F7.4
XL = 2 sin l sin ((90-b)/2)
81-82 Blank. 2X
83-89 Y Lambert coordinate: F7.4
YL = 2 cos l sin ((90-b)/2)
90-92 Blank. 3X
93-106 Supergalactic coordinates according to de
Vaucouleurs's new system (de Vaucouleurs et al.
1976, p. 8). The origin of longitude is at the
ascending node of the supergalactic equator
with the galactic equator. These coordinates
are calculated from the galactic coordinates.
93-98 Supergalactic longitude (degrees). F6.2
99-100 Blank. 2X
101-106 Supergalactic latitude (degrees). F6.2
107-109 Blank. 3X
110-113 Cluster radius (degrees): 0.09326 * diameter. F4.2
(See bytes 37-40.)
114-116 Blank. 3X
117-122 Cluster area (square degrees): 0.02733 * F6.3
diameter squared. (See bytes 37-40.)
123-125 Blank. 3X
126-130 Mean apparent population (galaxies per square I5
degree): population/area. (See bytes 30-33 and
bytes 117-122).
2-5
Table 2-3. File Contents (1 of 2): Cross Index
Suggested
Bytes Description Format
1 Blank. 1X
2- 5 Cluster number (1-9134). This file is in I4
ascending order by right ascension (bytes 8-14),
as file 2 of this catalogue (see Table 2-2).
This file cross-indexes the sequential cluster
number (this field) to the Zwicky plate-area
numbers.
6- 7 Blank. 2X
8-22 Equatorial coordinates (1950).
8-9 Hours of right ascension. I2
10 Blank. 1X
11-14 Minutes of right ascension. F4.1
15-16 Blank. 2X
17 Sign of declination A1
18-19 Degrees of declination. I2
20 Blank. IX
21-22 Arc minutes of declination. I2
23-24 Blank. IX
25-130 Zwicky plate numbers and cluster numbers
within the plates. This field has space for up to
twelve plate number-cluster number pairs, since
a cluster will often spread into several plate
areas. These pairs are sorted in increasing
order of plate-area number and run from left to
right. The plate-area numbers are those used
by Zwicky et al. For a cross-reference between
Zwicky plate-area numbers and Palomar
Observatory Sky Survey (POSS) plate-area
numbers, see Hill (1982). (References follow
Section 1 above.)
25-27 Lowest-numbered plate area I3
containing cluster.
28 Blank. 1X
29-31 Cluster number within plate area. I3
32-33 Blank. 2X
34-36 Next-lowest-numbered plate area I3
containing cluster (blank if none).
37 Blank. 1X
2-6
Table 2-3. File Contents (2 of 2): Cross Index
Suggested
Bytes Description Format
38-40 Cluster number within plate area I3
(blank if none).
41-130 Remaining plate-area and cluster 10(2X,I3,1X,
numbers, in increasing order of I3)
plate area: filled from left to
right. Fields without numbers
contain blanks.
2-7
SECTION 3 - FILE CHARACTERISTICS
The information in this section describes the logical structure of the
catalogue file or files. (Multiple values for an entry describe the
separate files of a multi-file catalogue.) A reminder to the user is
included of the physical tape attributes of which knowledge may be
required to read a tape copy of the catalogue.
Table 9-1. File Characteristics
Catalogue Abbreviation AZCL
Number of Files 3
Logical Record Length (Bytes) 130,130,130
Record Format (IBM OS/JCL) Fixed
Total Number of Logical Records 2712,9134,9134
Other attributes of the tape will vary from copy to copy, as their values
are discretionary, or else depend on the computer for which the tape was
copied. These include the following:
Number of Tracks
Density (Bits per Inch)
Blocksize (Bytes)
Blocking Factor (= Number of Logical Records per Block*)
Total Number of Blocks
Character Code
The values of these parameters for your tape are supplied separately.
You may wish to write them in above.
3-1
SECTION 4 - REMARKS AND MODIFICATIONS
The Catalogue of Abell and Zwicky Clusters of Galaxies was received by
the Astronomical Data Center (ADC), NASA Goddard Space Flight Center,
from the Centre de Donnees Stellaires (CDS) in 1979. The catalogue had
been prepared originally by the Bulgarian Academy of Sciences. As
received, the catalogue contained a file of documentation in addition to
the three data files. Section 2 of this document merely expands on that
documentation file. The only modifications to the catalogue format made
at the ADC are as follows:
(1) The sign of declination was moved so that it always appears in the
same byte (all three files).
(2) The declination of Zwicky cluster no. 2343 was given as -2 deg 21
arcmin and the type as 6, due to transposition of digits; the correct
values are -2 deg 26 arcmin and 1, respectively. This correction was
made to file 2, and to file 3 as well, since the incorrect
declination had been carried over there.
REFERENCES: See Section 1.
4-1
© UDS/CNRS