J/A+A/695/A59 Five superstructures in nearby Universe (Boehringer+, 2025)
Unveiling the largest structures in the nearby Universe:
Discovery of the Quipu superstructure.
Boehringer H., Chon G., Truemper J., Kraan-Korteweg R.C., Schartel N.
<Astron. Astrophys. 695, A59 (2025)>
=2025A&A...695A..59B 2025A&A...695A..59B (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; X-ray sources ; Redshifts
Keywords: galaxies: clusters: general - cosmic background radiation -
cosmology: observations - dark matter -
large-scale structure of Universe
Abstract:
For a precise determination of cosmological parameters we need to
understand the effects of the local large-scale structure of the
Universe on the measurements. They include modifications of the cosmic
microwave background, distortions of sky images by large-scale
gravitational lensing, and the influence of large-scale streaming
motions on measurements of the Hubble constant. The streaming motions,
for example, originate from mass concentrations with distances up to
250Mpc. In this paper we provide the first all-sky assessment of the
largest structures at distances between 130 and 250Mpc and discuss
their observational consequences, using X-ray galaxy clusters to map
the matter density distribution. Among the five most prominent
superstructures found, the largest has a length longer than 400Mpc
with an estimated mass of about 2e17 solar masses. This entity, which
we named Quipu, is the largest cosmic structure discovered to date.
These superstructures contain about 45% of the galaxy clusters, 30% of
the galaxies, 25% of the matter, and occupy a volume fraction of 13%,
thus constituting a major part of the Universe. The galaxy density is
enhanced in the environment of superstructures out to larger distances
from the nearest member clusters compared to the outskirts of clusters
in the field. We find superstructures with similar properties in
simulations based on LambdaCDM cosmology models. We show that the
superstructures should produce a modification on the cosmic microwave
background through the integrated Sachs-Wolf effect. Searching for
this effect in the Planck data we found a signal of the expected
strength, however, with low significance. Characterising these
superstructures is also important for astrophysical research, for
example the study of the environmental dependence of galaxy evolution
as well as for precision tests of cosmological models.
Description:
The paper gives a description of the five largest superstructures in
the nearby Universe as traced by galaxy clusters at redshifts from
0.03 to 0.06. The table provides the catalog of the 185 clusters,
which are contained in these superstructures.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
clusters.dat 60 185 Catalog of the 185 clusters which are contained
in the 5 superstructures
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See also:
J/A+A/656/A144 : Superclusters in local Universe at z≤0.03 (Bohringer+, 2021)
Byte-by-byte Description of file: clusters.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name CLASSIX cluster catalogue name,
RXCJHHMM.m+DDMM
18 I1 --- SSID [1/5] ID number of the superstructure (1)
21- 28 F8.4 deg RAdeg Right ascension (J2000)
30- 37 F8.4 deg DEdeg Declination (J2000)
39- 44 F6.4 --- z Redshift
48- 52 F5.3 10+37W LX500 X-ray luminosity (2)
55- 60 F6.3 10+14Msun M200 Mass in units of 1014 solar masses
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Note (1): The SSID refers to the following superstructures as follows:
1 = Quipu superstructure
2 = Shapley supercluster
3 = Serpens - Corona Borealis superstructure
4 = Extended Hercules supercluster
5 = Sculptor - Pegasus superstructure
Note (2): LX500 is given in units of 1044erg/s for a radius of r500,
the radius inside which the mean density of the cluster is 500 times the
critical density of the Universe at the redshift of the cluster
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Acknowledgements:
Hans Boehringer, hxb(at)mpe.mpg.de
(End) Patricia Vannier [CDS] 17-Feb-2025