scholarly journals A spectroscopic survey of Abell 1703: is it a rare relaxed cluster hosting a radio halo or a usual merging system?

2020 ◽  
Vol 492 (2) ◽  
pp. 2405-2417 ◽  
Author(s):  
W Boschin ◽  
M Girardi ◽  
F Gastaldello
Keyword(s):  
Gravitational Lensing ◽  
Statistical Tests ◽  
Galaxy Cluster ◽  
Theoretical Models ◽  
Sloan Digital Sky Survey ◽  
Cluster Galaxies ◽  
Radio Halo ◽  
Sky Survey ◽  
Galaxies Kinematics ◽  
First Moment

ABSTRACT We present the study of the internal dynamics of the intriguing galaxy cluster Abell 1703, a system hosting a probable giant radio halo whose dynamical status is still controversial. Our analysis is based on unpublished spectroscopic data acquired at the Italian Telescopio Nazionale Galileo and data publicly available in the literature. We also use photometric data from the Sloan Digital Sky Survey. We select 147 cluster members and compute the cluster redshift 〈z〉 ∼ 0.277 and the global line-of-sight velocity dispersion σv ∼ 1300 km s−1. We infer that Abell 1703 is a massive cluster: M200 ∼ 1–2 × 1015 M⊙. The results of our study disagree with the picture of an unimodal, relaxed cluster as suggested by previous studies based on the gravitational lensing analysis and support the view of a perturbed dynamics proposed by recent works based on Chandra X-ray data. The first strong evidence of a dynamically disturbed cluster comes from the peculiarity of the BCG velocity with respect to the first moment of the velocity distribution of member galaxies. Moreover, several statistical tests employed to study the cluster galaxies kinematics find significant evidence of substructure, being Abell 1703 composed by at least two or three subclumps probably caught after the core–core passage. In this observational scenario, the suspected existence of a radio halo in the centre of this cluster is not surprising and well agrees with the theoretical models describing diffuse radio sources in clusters.

scholarly journals AGN Activity in Brigtest Cluster Galaxies (BCGs)

2019 ◽  
pp. 153-158
Author(s):  
S. Fisek ◽  
S. Alis ◽  
E. K. Ülgen ◽  
F. K. Yelkenci
Keyword(s):  
Galaxy Cluster ◽  
Sloan Digital Sky Survey ◽  
Cluster Galaxies ◽  
Massive Galaxies ◽  
Brightest Cluster Galaxies ◽  
Sky Survey ◽  
Activity Types ◽  
Hα Emission ◽  
Deep Fields ◽  
The Universe

The aim of our study is to classify the Brightest Cluster Galaxies (BCG), which are the brightest and most massive galaxies in the universe and to determine fraction of BCGs showing AGN activity. Within the scope of the study, we combine BCGs from galaxy cluster catalogs which presented by Hao et al. (2010) and Wen et al. (2009) constructed from the SDSS (Sloan Digital Sky Survey) data and BCGs identified from CFHTLS (Canada-France-Hawaii Telescope Legacy Survey) Deep fields (Alis, 2009). Our combined sample contains 42490 BCGs. We determine activity types of BCGs by means of BPT diagrams and WISE color-color diagrams. 140 BCGs show AGN activity out of 42490. In addition, we calculated star formation rates (SFR) by using Hα emission lines for 5569 BCGs with suitable spectral data and investigated the correlation between SFR and redshift.

scholarly journals Searching for Mg ii absorbers in and around galaxy clusters

2021 ◽  
Vol 503 (3) ◽  
pp. 4309-4319
Author(s):  
Jong Chul Lee ◽  
Ho Seong Hwang ◽  
Hyunmi Song
Keyword(s):  
Galaxy Clusters ◽  
Detection Rate ◽  
Massive Star ◽  
Sloan Digital Sky Survey ◽  
Number Density ◽  
Cluster Galaxies ◽  
Star Forming ◽  
Quasar Spectra ◽  
Sky Survey ◽  
The Galaxy

ABSTRACT To study environmental effects on the circumgalactic medium (CGM), we use the samples of redMaPPer galaxy clusters, background quasars, and cluster galaxies from the Sloan Digital Sky Survey (SDSS). With ∼82 000 quasar spectra, we detect 197 Mg ii absorbers in and around the clusters. The detection rate per quasar is 2.7 ± 0.7 times higher inside the clusters than outside the clusters, indicating that Mg ii absorbers are relatively abundant in clusters. However, when considering the galaxy number density, the absorber-to-galaxy ratio is rather low inside the clusters. If we assume that Mg ii absorbers are mainly contributed by the CGM of massive star-forming galaxies, a typical halo size of cluster galaxies is smaller than that of field galaxies by 30 ± 10 per cent. This finding supports that galaxy haloes can be truncated by interaction with the host cluster.

scholarly journals The impact of disturbed galaxy clusters on the kinematics of active galactic nuclei

2020 ◽  
Vol 499 (3) ◽  
pp. 3792-3805
Author(s):  
Lawrence E Bilton ◽  
Kevin A Pimbblet ◽  
Yjan A Gordon
Keyword(s):  
Active Galactic Nuclei ◽  
Galaxy Clusters ◽  
Velocity Dispersion ◽  
Signal To Noise Ratio ◽  
Galactic Nuclei ◽  
Sloan Digital Sky Survey ◽  
X Ray ◽  
Cluster Galaxies ◽  
Sky Survey ◽  
The Impact

ABSTRACT We produce a kinematic analysis of AGN-hosting cluster galaxies from a sample of 33 galaxy clusters selected using the X-ray Clusters Database (BAX) and populated with galaxies from the Sloan Digital Sky Survey Data Release 8. The 33 galaxy clusters are delimited by their relative intensity of member galaxy substructuring as a proxy to core merging to derive two smaller sub-samples of 8 dynamically active (merging) and 25 dynamically relaxed (non-merging) states. The AGN were selected for each cluster sub-sample by employing the WHAN diagram to the strict criteria of log10([N ii]/Hα) ≥ −0.32 and EWHα ≥ 6 Å, providing pools of 70 mergings and 225 non-merging AGN sub-populations. By co-adding the clusters to their respective dynamical states to improve the signal-to-noise ratio of our AGN sub-populations we find that merging galaxy clusters on average host kinematically active AGN between 0–1.5r200 as r200 → 0, where their velocity dispersion profile (VDP) presents a significant deviation from the non-AGN sub-population VDP by ≳3σ. This result is indicative that the AGN-hosting cluster galaxies have recently coalesced on to a common potential. Further analysis of the composite distributions illustrates non-merging AGN-hosting sub-populations have, on average, already been accreted and predominantly lie within backsplash regions of the projected phase-space. This suggests merging cluster dynamical states hold relatively younger AGN sub-populations kinematically compared with those found in non-merging cluster dynamical states.

scholarly journals Probing the missing baryons with the Sunyaev-Zel’dovich effect from filaments

2019 ◽  
Vol 624 ◽  
pp. A48 ◽  
Author(s):  
Anna de Graaff ◽  
Yan-Chuan Cai ◽  
Catherine Heymans ◽  
John A. Peacock
Keyword(s):  
Gravitational Lensing ◽  
Sloan Digital Sky Survey ◽  
Low Density ◽  
Local Universe ◽  
Sky Survey ◽  
The Galaxy ◽  
Sunyaev Zel'dovich Effect ◽  
Galaxy Halo ◽  
The Universe ◽  
Sources Of Contamination

Observations of galaxies and galaxy clusters in the local universe can account for only ∼10% of the total baryon content. Cosmological simulations predict that the “missing baryons” are spread throughout filamentary structures in the cosmic web, forming a low-density gas with temperatures of 105−107 K. We search for this warm-hot intergalactic medium (WHIM) by stacking the Planck Compton y-parameter map of the thermal Sunyaev-Zel’dovich (tSZ) effect for 1 002 334 pairs of CMASS galaxies from the Sloan Digital Sky Survey. We model the contribution from the galaxy halo pairs assuming spherical symmetry, finding a residual tSZ signal at the 2.9σ level from a stacked filament of length 10.5 h−1 Mpc with a Compton parameter magnitude y = (0.6 ± 0.2)×10−8. We consider possible sources of contamination and conclude that bound gas in haloes may contribute only up to 20% of the measured filamentary signal. To estimate the filament gas properties we measure the gravitational lensing signal for the same sample of galaxy pairs; in combination with the tSZ signal, this yields an inferred gas density of ρb = (5.5 ± 2.9) × ρ̄b with a temperature T = (2.7 ± 1.7) × 106 K. This result is consistent with the predicted WHIM properties, and overall the filamentary gas can account for 11 ± 7% of the total baryon content of the Universe. We also see evidence that the gas filament extends beyond the galaxy pair. Averaging over this longer baseline boosts the significance of the tSZ signal and increases the associated baryon content to 28 ± 12% of the global value.

scholarly journals A gravitational lensing detection of filamentary structures connecting luminous red galaxies

2020 ◽  
Vol 633 ◽  
pp. A89 ◽  
Author(s):  
Qianli Xia ◽  
Naomi Robertson ◽  
Catherine Heymans ◽  
Alexandra Amon ◽  
Marika Asgari ◽  
...  
Keyword(s):  
Gravitational Lensing ◽  
Critical Density ◽  
Average Density ◽  
Sloan Digital Sky Survey ◽  
Weak Lensing ◽  
Luminous Red Galaxies ◽  
Sky Survey ◽  
Combining Data ◽  
Red Galaxies ◽  
Cluster Sequence

We present a weak lensing detection of filamentary structures in the cosmic web, combining data from the Kilo-Degree Survey, the Red Cluster Sequence Lensing Survey, and the Canada-France-Hawaii Telescope Lensing Survey. The line connecting luminous red galaxies with a separation of 3 − 5 h−1 Mpc was chosen as a proxy for the location of filaments. We measured the average weak lensing shear around ∼11 000 candidate filaments selected in this way from the Sloan Digital Sky Survey. After nulling the shear induced by the dark matter haloes around each galaxy, we reported a 3.4σ detection of an anisotropic shear signal from the matter that connects them. Adopting a filament density profile, motivated from N-body simulations, the average density at the centre of these filamentary structures was found to be 15 ± 4 times the critical density.

scholarly journals Composite Luminosity Functions Based on the Sloan Digital Sky Survey “Cut and Enhance” Galaxy Cluster Catalog

2002 ◽  
Vol 54 (4) ◽  
pp. 515-525 ◽  
Author(s):  
Tomotsugu Goto ◽  
Sadanori Okamura ◽  
Timothy A. Mckay ◽  
Neta A. Bahcall ◽  
James Annis ◽  
...  
Keyword(s):  
Galaxy Cluster ◽  
Sloan Digital Sky Survey ◽  
Luminosity Functions ◽  
Sky Survey

scholarly journals Preferred Alignments of Angular Momentum Vectors of Galaxies in the SDSS Supercluster S[202-001+0084]

NUTA Journal ◽  
2019 ◽  
Vol 6 (1-2) ◽  
pp. 12-17
Author(s):  
Janak Ratna Malla ◽  
Binil Aryal ◽  
Walter Saurer
Keyword(s):  
Angular Momentum ◽  
Galaxy Formation ◽  
Particle Physics ◽  
Statistical Tests ◽  
Three Dimensional ◽  
Sloan Digital Sky Survey ◽  
Sky Survey ◽  
Hierarchy Model ◽  
Vector Orientation ◽  
Almost All

We present a study of spin vector orientation of 1331 SDSS (Sloan Digital Sky Survey) galaxies in SDSS Supercluster S[202-001+0084] having redshift 0.02 to 0.03. The data are provided by our collaborator, Institute of Astro-particle Physics, Innsbruck University, Austria. We have converted two dimensional data to three dimensional by Godlowskian Transformation. Our aim is to find out non-random effects in the preferred alignments of angular momentum vectors of galaxies. In general, no preferred alignments angular momentum vectors of galaxies are noticed, supporting Hierarchy model of galaxy formation. In almost all sub samples the 1st order Fourier coefficient suggests that the angular momentum vectors are randomly oriented but other statistical tests suggest anisotropic distribution probably due to the binning effect and gravitational shearing effect.

scholarly journals The rotational profiles of cluster galaxies

2019 ◽  
Vol 490 (4) ◽  
pp. 5017-5032 ◽  
Author(s):  
Lawrence E Bilton ◽  
Matthew Hunt ◽  
Kevin A Pimbblet ◽  
Elke Roediger
Keyword(s):  
Galaxy Clusters ◽  
Extreme Environments ◽  
Sloan Digital Sky Survey ◽  
Cluster Galaxies ◽  
Main Cluster ◽  
Sky Survey ◽  
Two Samples ◽  
Core Rotation ◽  
Blue Galaxy ◽  
Additional Sample

ABSTRACT We compile two samples of cluster galaxies with complimentary hydrodynamic and N-body analysis using flash code to ascertain how their differing populations drive their rotational profiles and to better understand their dynamical histories. We select our main cluster sample from the X-ray Galaxy Clusters Database (BAX), which are populated with Sloan Digital Sky Survey (SDSS) galaxies. The BAX clusters are tested for the presence of substructures, acting as proxies for core mergers, culminating in sub-samples of eight merging and 25 non-merging galaxy clusters. An additional sample of 12 galaxy clusters with known dumbbell components is procured using galaxy data from the NASA/IPAC Extragalactic Database (NED) to compare against more extreme environments. BAX clusters of each sample are stacked on to a common RA–Dec. space to produce rotational profiles within the range of 0.0–2.5 r200. Merging stacks possess stronger core rotation at ≲0.5r200 primarily contributed by a red galaxy sub-population from relaxing core mergers; this is alongside high rotational velocities from blue galaxy sub-populations, until they mix and homogenize with the red sub-populations at ∼r200, indicative of an infalling blue galaxy sub-population with interactive mixing between both sub-populations at ≳ r200. flash code is utilized to simulate the merger phase between two originally independent clusters and test the evolution of their rotational profiles. Comparisons with the dumbbell clusters leads to the inference that the peculiar core rotations of some dumbbell clusters are the result of the linear motions of core galaxies relaxing on to the potential during post second infall.

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