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J/MNRAS/289/263 Galaxy clusters from the APM galaxy survey (Dalton+ 1997)
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The APM galaxy survey - V. Catalogues of galaxy clusters.
Dalton G.B., Maddox S.J., Sutherland W.J., Efstahiou G.
<Mon. Not. R. Astron. Soc. 289, 263 (1997)>
=1997MNRAS.289..263D (SIMBAD/NED BibCode)
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ADC_Keywords: Clusters, galaxy
Keywords: catalogues - surveys - galaxies: clusters: general -
large-scale structure of the Universe
Abstract:
We describe the construction of catalogues of galaxy clusters from the
APM Galaxy survey using an automated algorithm based on Abell-like
selection criteria. We investigate the effects of varying several
parameters in our selection algorithm, including the magnitude range
and radius from the cluster centre used to estimate the cluster
richnesses. We quantify the accuracy of the photometric distance
estimates by comparing them with measured redshifts, and we
investigate the stability and completeness of the resulting
catalogues. We find that the angular correlation functions for
different cluster catalogues are in good agreement with one another,
and are also consistent with the observed amplitude of the spatial
correlation function of rich clusters.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog 57 957 The APM cluster catalogue
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See also:
J/MNRAS/278/1025 : The APM Bright Galaxy Catalogue (Loveday 1996)
J/MNRAS/246/433 : APM galaxy survey. II. (Maddox+ 1990)
J/MNRAS/269/151 : APM galaxy survey. IV. (Dalton+, 1994)
J/MNRAS/274/1071 : Edinburgh-Milano cluster redshift survey (Collins+ 1995)
VII/203 : Las Campanas Redshift Survey (Shectman+ 1996)
Byte-by-byte Description of file: catalog
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Bytes Format Units Label Explanations
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1- 3 I3 --- Cluster Cluster number
5- 6 I2 h RAh Right ascension (1950)
7- 8 I2 min RAm Right ascension (1950)
9- 12 F4.1 s RAs Right ascension (1950)
14 A1 --- DE- Declination sign
15- 16 I2 deg DEd Declination (1950)
17- 18 I2 arcmin DEm Declination (1950)
19- 20 I2 arcsec DEs Declination (1950)
22- 26 F5.2 mag Xmag X magnitude (1)
28- 31 F4.1 arcmin rC Projected radius
33- 37 F5.3 --- z Estimated redshift determined from Xmag
39- 43 F5.1 --- R Cluster richness
44 A1 --- n_R [abc] Notes (2)
46- 50 F5.3 --- zabs ? Absorption redshift
52- 56 A5 --- n_zabs [12345+, ] Notes (3)
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Note (1): We define Xmag to be the magnitude for which C_i_=X, i.e. in the case
of X=10 with no weighting then Xmag is exactly equivalent to Abell's
m_10_. (C_i_ is the weighted sum of galaxies brighter than m_i_
minus the expected background count brighter than m_i_.)
Note (2): a: This cluster is close to a bright star which has been excised from
the galaxy catalogue. A part of the cluster area is therefore
missing from the survey data and so the richness may have been
underestimated.
b: The field of this cluster includes a 2-arcmin foreground galaxy
0.7r_C_ from the centre which has been broken up into several
small galaxian images by the APM software. These additional
objects may have caused the richness to be slightly overestimated.
c: This field is dominated by a 2-arcmin foreground galaxy which has
been broken up into several small galaxian images by the APM
software. The field does not appear to contain a true cluster. The
cluster was below the richness threshold used by Dalton et al.
(1994MNRAS.271L..47D) and was not visually inspected at the time
of those observations.
Note (3): 1: Redshift from Paper IV, Dalton et al., 1994, Cat. <J/MNRAS/269/151>
2: Redshift measured by Dalton et al. (1994MNRAS.271L..47D). Note that
this survey was limited to Xmag <=19.2
3: Redshift measured as part of the deep extension to the APM cluster
redshift survey (Croft et al., 1997, MNRAS, in press)
4: Cluster found in the Edinburgh-Milano Cluster Redshift Surcey
(Collins et al., 1995, Cat. <J/MNRAS/274/1071>). If only one
references is present then the redshift is adopted from this
source, otherwise this entry indicates that the cluster is also
found in that survey.
5: Cluster redshift has been drawn from Las Campanas Redshifdt Survey
(LCRS: Schectman et al., 1996ApJ...470..172S. Cat. <VII/203>)
+: For the cluster APM 100, we have adopted the value given by
Collins et al. (1995, Cat. <J/MNRAS/274/1071>) as they point out
this is in better agreement with the maximum likelihood redshift
estimate quoted in Paper IV (Cat. <J/MNRAS/269/151>) than our
single galaxy redshift.
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Acknowledgements: Gavin Dalton <g.dalton1@physics.ox.ac.uk>
References:
Maddox et al., Paper I. 1990MNRAS.243..692M
Maddox et al., Paper II. 1990MNRAS.246..433M, Cat. <J/MNRAS/246/433>
Maddox et al., Paper III. 1996MNRAS.283.1227M
Dalton et al., Paper IV. 1994MNRAS.269..151D, Cat. <J/MNRAS/269/151>
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(End) Patricia Bauer [CDS] 10-Oct-1997