J/MNRAS/481/1055 ShaSS filamentary network connecting clusters (Haines+, 2018)
Shapley Supercluster Survey: mapping the filamentary network connecting the
clusters.
Haines C.P., Busarello G., Merluzzi P., Pimbblet K.A., Vogt F.P.A.,
Dopita M.A., Mercurio A., Grado A., Limatola L.
<Mon. Not. R. Astron. Soc., 481, 1055-1074 (2018)>
=2018MNRAS.481.1055H 2018MNRAS.481.1055H (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs ; Clusters, galaxy ; Redshifts
Keywords: catalogues, galaxies: clusters: general -
large-scale structure of Universe - cosmology: observations -
galaxies: clusters: individual: A3552, A3554, A3556, A3558, A3559,
A3560, A3562
Abstract:
We have mapped the structure and connectivity of the Shapley
supercluster core and its surroundings as traced by its member
galaxies. To achieve this, we have carried out a new redshift survey
of galaxies across a 21 square degree region (17x17Mpc2) of the
Shapley supercluster containing 11 rich clusters, all lying at
z∼0.048. This survey aims to provide full spectroscopic coverage of
galaxies for the Shapley Supercluster Survey (ShaSS), a
multiwavelength survey based on high-quality optical ugri and
near-infrared K-band imaging acquired with the 2.6-m VST and 4.1-m
VISTA telescopes. Targets were selected from the VST images as having
i<18.0 and WISE/W1<15.5mag, and the observations were carried out with
the AAOmega spectrograph on the 3.9-m Anglo-Australian Telescope. We
present here redshift measurements for 4037 galaxies, of which 957
belong to the Shapley Supercluster. Including existing measurements,
there are now reliable redshifts for 95 per cent of galaxies within
the survey's magnitude limits over the 21deg2 region. This has
enabled us to: (i) obtain a detailed map of the galaxy number density
across the whole region; (ii) identify new groups and cluster
substructures; (iii) establish the existence of a stream of galaxies
connecting A3559 to the supercluster core. We provide updated central
redshifts and velocity dispersions of the 11 clusters, confirming that
they all lie within 1300km/s of the central cluster Abell3558. These
11 systems are all inter-connected and lie within a coherent sheet of
galaxies that fills the entire survey region without gaps. Clear
velocity caustics extend right to the survey boundary, indicating that
the entire structure is gravitationally bound and in the process of
collapse.
Description:
The ShaSS (Merluzzi et al. 2015MNRAS.446..803M 2015MNRAS.446..803M) is based on VST
optical imaging (Capaccioli & Schipani 2011Msngr.146....2C 2011Msngr.146....2C), acquired
within the Italian INAF Guaranteed Time of Observations (PI: P.
Merluzzi). The OmegaCAM instrument (Kuijken 2011Msngr.146....8K 2011Msngr.146....8K) on
the VST has a corrected field of view of 1degx1deg, enabling the whole
ShaSS area to be covered with 23 VST fields. Each field was observed
in four optical bands, u (texp=2955s), g (1400s), r (2664s), and i
(1000s), reaching 5σ (AB) magnitude limits of 24.4, 24.6, 24.1,
and 23.3, respectively (Mercurio et al. 2015MNRAS.453.3685M 2015MNRAS.453.3685M). While
observations for all four bands took place contemporaneously from 2012
February onwards, the highest priority was given to the i-band
observations, to ensure that complete coverage of the entire survey
region was obtained in one band as soon as possible, in order to
prepare targets for the redshift survey.
Our spectroscopic observations were carried out using the AAOmega
system (Smith et al. 2004SPIE.5492..410S 2004SPIE.5492..410S; Sharp et al.
2006SPIE.6269E..0GS) on the 3.9m Anglo Australian Telescope, on the
four nights of 2013 May 9-12. AAOmega consists of the 2dF fibre
positioner (Lewis et al. 2002MNRAS.333..279L 2002MNRAS.333..279L), linked to a stable,
bench-mounted dual-beam spectrograph. The 2dF positioner can place 392
fibres, with 2arcsec projected diameter, across a 2deg diameter field
of view. A further eight fibre bundles are used for guiding.
Observations were carried out with 580V and 385R gratings on the blue
and red arm, respectively, covering the wavelength range 370-880 nm at
a resolution of λ/Δλ∼1300. The integration time
for each configuration was 1.5h, split into three 1800s exposures.
In total, we have obtained reliable redshifts for 4037 unique galaxies
through our AAOmega observations. The complete catalogue of these
redshifts is published here in Table 5.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 60 4037 Galaxy redshifts
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- ID ShaSS galaxy ID (ShaSSNNNNNNNNN)
16- 26 F11.7 deg RAdeg Right ascension (J2000)
28- 38 F11.7 deg DEdeg Declination (J2000)
40- 45 F6.3 mag imag i-band Kron magnitude
47- 53 E7.5 --- z Redshift measured from the AAOmega spectra
55- 60 E6.4 --- e_z Error on z
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 08-Jun-2022