J/ApJ/723/985 Orientation of galaxies in galaxy clusters (Godlowski+, 2010)
The orientation of galaxies in galaxy clusters.
Godlowski W., Piwowarska P., Panko E., Flin P.
<Astrophys. J., 723, 985-992 (2010)>
=2010ApJ...723..985G 2010ApJ...723..985G
ADC_Keywords: Clusters, galaxy ; Positional data
Keywords: galaxies: clusters: general
Abstract:
We present an analysis of the spatial orientations of galaxies in 247
optically selected rich Abell clusters which have at least 100 members
in the considered area. We investigated the relation between angles
that give information about galaxy angular momenta and the number of
members in each structure. The position angles of the galaxies' major
axes, as well as two angles describing the spatial orientation of the
galaxy plane, were tested for isotropy by applying three different
statistical tests. It is found that the values of the statistics
increase with the amount of the galaxies' members, which is equivalent
to the existence of a relation between anisotropy and the number of
galaxies in a cluster. The search for connection between the galaxies'
alignments and Bautz-Morgan (BM) morphological types of examined
clusters showed a weak dependence. A statistically marginal relation
between velocity dispersion and cluster richness was observed. In
addition, it was found that the velocity dispersion decreases with BM
type at almost 3σ level. These results show the dependence of
alignments with respect to clusters' richness, which can be regarded
as an environmental effect.
Description:
Our paper is based on the analysis of structures taken from the PF
catalog (Panko & Flin 2006, Cat. J/other/JAD/12.1). The structures
were extracted from the Muenster Red Sky Survey (MRSS hereafter;
Ungruhe et al. 2003JAD.....9....1U 2003JAD.....9....1U). MRSS is optical large-scale
survey covering an area of 5000deg2 in the southern hemisphere.
After scanning 217 ESO plates, it gives information for about 5.5
million galaxies. The data for each galaxy member were taken from the
MRSS. These include the equatorial coordinates of galaxies, the
diameters of the major and minor axes of the galaxy image, and the
position angle of the major axis. In the present paper, we selected
rich clusters having at least 100 members and identified with one of
the ACO clusters (Abell et al. 1989, Cat. VII/110), which gave us the
Bautz-Morgan morphological types (BM types). Data dealing with
velocity dispersion of galaxies were taken from the literature.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 65 248 The list of investigated clusters
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See also:
B/eso : ESO Science Archive Catalog (ESO, 2012)
VII/165 : Measured Redshifts of Abell Clusters of Galaxies (Andernach 1991)
VII/110 : Rich Clusters of Galaxies (Abell+ 1989)
VII/88 : CEDAG Catalogue of Clusters of Galaxies (Fernandez+ 1984)
J/other/JAD/12.1 : Cat. of galaxy structures based on the MRSS (Panko+, 2006)
J/MNRAS/329/87 : 2dF Galaxy Redshift Survey: galaxy clusters (de Propris+,
2002)
J/ApJS/125/35 : ACO clusters redshifts and velocity dispersions (Struble+
1999)
J/A+A/310/31 : The ESO Nearby Abell Cluster Survey. II. (Mazure+ 1996)
J/ApJS/95/401 : Clusters of galaxies position angles (Plionis 1994)
J/AJ/108/1 : Flatness of clusters of galaxies (Struble+ 1994)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- PF Panko-Flin (2006, Cat. J/other/JAD/12.1)
catalog identification (NNNN-NNNN)
11- 20 F10.7 h RAhour Cluster center Right Ascension in decimal hours
(J2000)
22- 31 F10.6 deg DEdeg Cluster center Declination in decimal degrees
(J2000)
33- 35 I3 --- N0 Number of galaxies in the field of structure
37- 39 I3 --- N1 Number of galaxies with b/a≤0.75
41- 45 A5 --- ACO Abell et al. 1989 (Cat. VII/110) structure
identification (sNNNN or ANNNN)
47- 48 A2 --- p [xyz0a? ] Galaxies alignement: position angle p (1)
56- 57 A2 --- delD [xyz0a? ] Galaxies alignement: polar angle
δD (1)
65 A1 --- eta [0?rta] Galaxies alignement: azimuthal angle
η (1)
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Note (1): Code for galaxies' alignments with respect to supergalactic
coordinate system as follows:
0 = isotropic distribution.
? = situation that we can not decided if it's an anisotropic or
isotropic distribution.
xy = spin vector tends to be parallel to supergalactic plane for
supergalactic position angle p and polar angle δD
(|| in the printed table)
z = spin vector tends to be perpendicular to the supergalactic plane
for supergalactic position angle p and polar angle δD
(⊥ in the printed table)
r = the projection of the spin vector to the supergalactic plane tends
to be parallel to the direction of the Virgo Cluster (Supercluster
center) (|| in the printed table)
t = the projection of the spin vector to the supergalactic plane tends
to be perpendicular to the direction of the Virgo Cluster (Supercluster
center) (⊥ in the printed table)
a = anisotropic distribution but no special direction of deviation from
isotropy (especially parallel or perpendicular) was found
(oblique arrow in the printed table)
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 20-Jul-2012