J/A+A/637/A31 Cluster in superclusters of galaxies (Santiago-Bautista+, 2020)
Identification of filamentary structures in the environment of superclusters
of galaxies in the Local Universe.
Santiago-Bautista I., Caretta C.A., Bravo-Alfaro H., Pointecouteau E.,
Andernach H.
<Astron. Astrophys. 637, A31 (2020)>
=2020A&A...637A..31S 2020A&A...637A..31S (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Redshifts ; Velocity dispersion
Keywords: galaxies: groups: general - galaxies: clusters: general -
large scale structure of the Universe - methods: data analysis -
galaxies: evolution
Abstract:
The characterization of the internal structure of the superclusters of
galaxies (walls, filaments and knots where the clusters are located)
is paramount for understanding the formation of the Large Scale
Structure and for outlining the environment where galaxies evolved in
the last Gyr.
(i) To detect the compact regions of high relative density (clusters
and rich groups of galaxies); (ii) to map the elongated structures of
low relative density (filaments, bridges and tendrils of galaxies);
(iii) to characterize the galaxy populations on filaments and study
the environmental effects they are subject to.
We employed optical galaxies with spectroscopic redshifts from the
SDSS-DR13 inside rectangular boxes encompassing the volumes of a
sample of 46 superclusters of galaxies, up to z=0.15. A virial
approximation was applied to correct the positions of the galaxies in
the redshift space for the "finger of God" projection effect. Our
methodology implements different classical pattern recognition and
machine learning techniques (Voronoi tessellation, hierarchical
clustering, graph-network theory, minimum spanning trees, among
others), pipelined in the Galaxy Systems-Finding algorithm and the
Galaxy Filaments-Finding algorithm.
We detected in total 2705 galaxy systems (clusters and groups, of
which 159 are new) and 144 galaxy filaments in the 46 superclusters of
galaxies. The filaments we detected have a density contrast above 3,
with a mean value around 10, a radius of about 2.5h70-1Mpc and
lengths between 9 and 130h70-1Mpc. Correlations between the galaxy
properties (mass, morphology and activity) and the environment in
which they reside (systems, filaments and the dispersed component)
suggest that galaxies closer to the skeleton of the filaments are more
massive by up to 25% compared to those in the dispersed component; 70%
of the galaxies in the filament region present early type morphologies
and the fractions of active galaxies (both AGN and SF) seem to
decrease as galaxies approach the filament.
Our results support thee idea that galaxies in filaments are subject
to environmental effects leading them to be more massive (probably due
to larger rates of both merging and gas accretion), less active both
in star formation and nuclear activity, and prone to the
density-morphology relation. These results suggest that preprocessing
in large scale filaments could have significant effects on galaxy
evolution.
Description:
We selected a sample of superclusters of galaxies from the Main
SuperCluster Catalogue (MSCC, Chow-Martinez et al.,
2014MNRAS.445.4073C 2014MNRAS.445.4073C, Cat. J/MNRAS/445/4073), which are inside the SDSS
region (in order to have a sample of galaxy data as homogeneous as
possible).
Our final sample consists of 46 superclusters of galaxies,
which are listed in Table 1.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 200 46 Sample of MSCC superclusters used in the
present work
table3.dat 140 2705 Main properties of the systems identified in the
volume of the supercluster MSCC310
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See also:
J/MNRAS/445/4073 : Two catalogues of superclusters (Chow-Martinez+, 2014)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- MSCC [55/586] Supercluster name
5- 8 A4 --- Name Proper name of the supercluster
10- 15 F6.2 deg RAdeg Supercluster mean right ascension (J2000)
18- 22 F5.2 deg DEdeg Supercluster mean declination (J2000)
24- 29 F6.4 --- zmean Mean redshift of the supercluster
31- 32 I2 --- NCl Richness (number of member clusters) (1)
34 I1 --- Nfil Number of filament candidates found previously
in each supercluster
36-200 A165 --- Abell Abell/ACO cluster members names
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Note (1): The superclusters have five or more Abell cluster members, with
z≤0.15, and inside the SDSS-DR13 region.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- MSCC [55/579] Supercluster name
5- 7 I3 --- SCI-ID [1/305] System identification number within
the supercluster
9- 11 I3 --- Nmem [5/578] Richness (number of member in the
system)
13- 25 F13.9 deg RAdeg [0.8/359.2] Right ascension of the final
system centroid (J2000)
27- 41 F15.11 deg DEdeg [-10.3/68.1] Declination of the final
system centroid (J2000)
43- 54 F12.10 --- z [0.0/0.2] Redshift of the final system
centroid
56- 67 F12.8 deg RABdeg [1.0/359.2] Right ascension of the
brightest member of the system (J2000)
69- 83 F15.11 deg DEBdeg [-10.3/68.1] Declination of the
brightest member of the system (J2000)
85- 96 F12.10 --- zB [0.0/0.2] Redshift of the brightest
member of the system
98-109 F12.7 km/s sigma [14.6/2251.2] Velocity dispersion
calculated for the system
111-122 F12.10 Mpc Rh [0.0/2.3] Harmonic radius calculated for
the system (in h70-1Mpc unit)
124-135 F12.10 Mpc Rvir [0.0/3.6] Virial radius calculated for
the system (in h70-1Mpc unit)
137-140 I4 --- ACO [0/2593]?=0 Cross-reference with Abell clusters
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Acknowledgements:
Iris Santiago-Bautista, isantiago(at)irap.omp.eu
(End) Patricia Vannier [CDS] 05-Apr-2020