VII/84A Groups of Galaxies. III. The CfA Survey (Geller+ 1983)
Groups of Galaxies. III. The CfA Survey
Geller M.J., Huchra J.P.
<Astrophys. J. Suppl. Ser. 52, 61 (1983)>
=1983ApJS...52...61G 1983ApJS...52...61G
ADC_Keywords: Clusters, galaxy ; Galaxy catalogs
Description:
The catalog contains statistically homogeneous groups of galaxies
based on the Harvard-Smithsonian Center for Astrophysics (CfA)
redshift survey. Groups in the catalog are all density enhancements in
redshift space of a factor greater than 20. All groups contain at
least three members. There are 176 groups in the catalog and 102
groups have been identified in one or more previous studies.
The catalog includes group numbers, numbers of members, equatorial
coordinates, mean flow-corrected galactocentric velocities,
line-of-sight-velocity dispersion, integrated group magnitudes,
crossing times for the groups, and mean harmonic radii of the groups.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
groups.dat 45 176 CfA redshift survey data for 176
galaxy groups (Table1 of paper)
crossid.dat 37 196 Comparison against previous catalogs
(Table3 of paper)
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See also:
VII/86 : Groups of Galaxies. I. (Huchra & Geller 1982)
VII/164 : The CfA Redshift Catalogue, Version Nov. 1993 (Huchra+, 1993)
Byte-by-byte Description of file: groups.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- GrpNum [1/176]+ Group running number
4- 7 I4 --- NumGal Number of Galaxies composing this group
8-10 I3 h RAh Right Ascension (1950) hours
11-14 F4.1 min RAm RA in minutes
16 A1 --- DE- Sign of Declination
17-18 I2 deg DEd Declination (1950) in degrees
19-20 I2 arcmin DEm DEC in arcminutes
21-25 I5 km/s GCvel *GC velocity
26-30 I5 km/s Vdisp *LOS vel. disp.
31-35 F5.1 mag GrpMag Integrated group magnitude
36-40 F5.2 --- H*xTime *Crossing time
41-45 F5.2 Mpc Mradius *Mean harmonic radius
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Note on GCvel:
Mean flow-corrected galactocentric velocity in km/sec.
Note on Vdisp:
Line-of-sight velocity dispersion, uncorrected for measurement error, in
km/sec.
Note on H*xTime:
Crossing time of the group in units of 1/H. This field was mislabeled in
Geller and Huchra (1983) (see History).
Note on Mradius:
Mean harmonic radius of the group as defined by equation (13) of Huchra
and Geller (1982), in Mpc. This field was mislabeled in Geller and
Huchra (1983) (see Remarks and Modifications).
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Byte-by-byte Description of file: crossid.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- GrpNum [1/176]+= Catalog number of the group
5- 9 A5 --- TGnum *TG number(s)
11-12 I2 --- HGnum ? Huchra and Geller (1982ApJ...257..423H 1982ApJ...257..423H)
15-16 I2 --- DVnum ? de Vaucouleurs (1975) group number
20-37 A18 --- Alias Other names of groups in this cluster
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Note on TGnum:
Corresponding TG group (Turner and Gott =1976ApJS...32..409T 1976ApJS...32..409T), if any.
This may be a range; for example, 50-57 for GOGIII group 94.
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Remarks and Modifications:
The (GOGIII) 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 original tape consisted of two text files of data from Tables 1 and
3 in the published catalog Huchra and Geller (1982). Blank columns were
removed from Table 1 using an editor to reduce the record size from 54
to 45 bytes. The character "-", used in Table 3 to indicate no data, was
changed to a blank, so that most of the fields could be read with a
FORTRAN integer format. No other changes were made in either file.
A FORTRAN program was run to check the validity of each field according
to its data type and value.
In the original published catalog (Geller and Huchra 1983) the crossing
time and mean harmonic radius fields were mislabeled (erratum, Geller
and Huchra 1984). We wish to thank J. P. Huchra for bringing this to our
attention.
The second file, crossid.dat, contains a table comparing the present
catalog against three earlier catalogs: DV = de Vaucouleurs (1975);
HG = Huchra and Geller (1982); TG = Turner and Gott (1976)
Acknowledgements:
The original ADC documentation by Anne C. Raugh (1987) was used to
create this ReadMe file.
References:
Geller, M. J. and Huchra, J. P. =1983ApJS...52...61G 1983ApJS...52...61G
(Erratum in ApJS 54, 442)
Huchra, J. P. and Geller, M. J. =1982ApJ...257..423H 1982ApJ...257..423H
Turner, E. L. and Gott, J. R. =1976ApJS...32..409T 1976ApJS...32..409T
de Vaucouleurs, G. 1975, in Stars and Stellar Systems, Galaxies and the
Universe, Vol. 9, ed. A. Sandage, M. Sandage, and J. Kristian
(Chicago: University of Chicago Press), p. 557.
(End) C.-H. Joseph Lyu [Hughes STX/NASA] 12-Dec-1995