J/AJ/108/1 Flatness of clusters of galaxies (Struble+ 1994)
The intrinsic shape of clusters of galaxies: correlations among
flattening, richness, and velocity dispersion
Struble M.F., Ftaclas C.
<Astron. J. 108, 1 (1994)>
=1994AJ....108....1S 1994AJ....108....1S
ADC_Keywords: Clusters, galaxy ; Morphology ; Velocity dispersion
Abstract:
We examine relations between shape, richness, and velocity dispersion
for a sample of 350 clusters of galaxies of all morphologies,
including those with visible substructure. For our sample the apparent
shape of clusters is correlated with velocity dispersion and Abell
(1958ApJS....3..211A 1958ApJS....3..211A) richness in the sense that poor, low dispersion
clusters are flatter in the mean than their richer, higher dispersion
counterparts. These characteristics are also exhibited by the X-ray
emitting gas. There are virtually no highly flattened clusters having
high richness or high velocity dispersions in the sample. We find that
the variation of richness and velocity dispersion with apparent shape
is too steep to be assigned to projection effects, and conclude rich,
high dispersion clusters are intrinsically more nearly spherical than
poorer clusters and that two-body relaxation is probably not an
effective anisotropy damping mechanism in Abell clusters.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 103 344 Cluster properties and flattenings
refs.dat 158 62 References to table 1
table2.dat 57 8 Statistics of sample characteristics
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See also:
VII/110 : Rich Clusters of Galaxies (Abell+ 1989)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Cluster name (mainly Abell's, Cat. VII/110)
11- 13 I3 --- NA Abell's count of galaxies
15- 18 I4 km/s Sigma ? Velocity dispersion
20- 27 A8 --- r_Sigma Reference for Sigma, in refs.dat file
29- 30 A2 --- RStyp Rood-Sastry (1971PASP...83..313R 1971PASP...83..313R)
morphological type
33- 37 A5 --- BMtyp Bautz-Morgan (1970ApJ...162L.149B 1970ApJ...162L.149B)
morphological type (2)
39- 42 F4.2 --- fCM ? Carter and Metcalfe (1980MNRAS.191..325C 1980MNRAS.191..325C)
flatness (a/b)
44- 47 F4.2 --- fB1 ? Binggeli (1982A&A...107..338B 1982A&A...107..338B)
flatness (a/b)
49- 52 F4.2 --- fWB ? West & Bothum (1990ApJ...350...36W 1990ApJ...350...36W)
flatness (a/b)
54- 57 F4.2 --- fRHK ? Rhee et al. (1991A&AS...91..513R 1991A&AS...91..513R)
flatness (a/b)
59- 62 F4.2 --- fL ? Plionis et al. (1991MNRAS.249..662P 1991MNRAS.249..662P)
flatness (a/b)
64- 67 F4.2 --- fTP ? Tucker & Peterson (1988AJ.....95..298T 1988AJ.....95..298T)
flatness (a/b)
70- 73 F4.2 --- fS ? Struble (1985AJ.....90..582S 1985AJ.....90..582S) flatness (a/b)
75- 82 A8 --- r_fS References for fS, in refs.dat file
85- 88 F4.2 --- fOther ? Flatness form other works
90- 97 A8 --- r_fOther References for fOther, in refs.dat file
100-103 F4.2 --- f* Mean value of the flatness (1)
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Note (1): The last digit on the bottom of the first page of table 1
could not be read; they were replaced by a blank.
It concerns Numbers 257, 260, 272, 274, 275 and 367.
Note (2): BMtyp is frequently "I-III" which does not exist. Most of
these types should be read as "II-III" except for Abell 77 (I),
Abell 2384 and 3528 (II). There are a few futher inconsistencies
in the BM types for Abell 367, 924, 2319 and 2634
[Note by H. Andernach, March 2007]
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode BibCode
24- 44 A21 --- Aut Author's name
46-158 A113 --- Com Comments
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Sample Sample designation
5- 7 I3 --- N Number of clusters in the sample
9- 14 F6.4 --- Mean flatness
17- 22 F6.4 --- e_ Dispersion in mean flatness
24- 29 F6.4 --- log log of mean flatness
31- 36 F6.4 --- Mean of logf (log of the geometric mean)
38- 43 F6.4 --- e_ Dispersion in logf
45- 50 F6.4 --- O-C Difference between the observed and
computed
52- 57 F6.4 --- A(S) Characteristic factor defined by
A(S)=≪logf≫/<logf(S)>, where S is the sample
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Table 2. (b) Correlation statistics between sample
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Correlation Number in Correlation
common Coefficient
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B1 vs TP 8 0.53
B1 vs S 19 0.77
CM vs L 10 0.85
CM vs S 15 0.70
TP vs WB 4 0.76
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Historical Notes:
* Keypunched at CDS
* 07-Nov-2002: DC0003-05 corrected in DC0003-50, in table1.dat
* 14-Nov-2003: 1 bibcode corrected in refs.dat file
* 27-Mar-2007: a few typos in morphological types of table1.dat
communicated by H. Andernach
(End) James Marcout, Patricia Bauer [CDS] 10-May-1996