Compact groups of galaxies (CGs) from the SDSS Data Release 6

Open Physics ◽  
2008 ◽  
Vol 6 (2) ◽  
Author(s):  
Xin-Fa Deng ◽  
Ji-Zhou He ◽  
Xin-sheng Ma ◽  
Peng Jiang ◽  
Xiao-Xun Tang
Keyword(s):  
Cluster Analysis ◽  
Velocity Dispersion ◽  
Three Dimensional ◽  
Compact Groups ◽  
Groups Of Galaxies ◽  
Main Galaxy ◽  
Crossing Time ◽  
Data Release ◽  
Galaxy Sample ◽  
Virial Mass

AbstractFrom the volume-limited MAIN galaxy sample of the SDSS Data Release 6 (SDSS6), we have identified 1298 compact groups of galaxies (CGs) at the neighbourhood radius of R = 1.2 Mpc by three-dimensional cluster analysis. In order to compile the CG catalog, we also estimated velocity dispersion, virial radius, virial mass and crossing time of CGs. In addition, our results show that properties of galaxies may not correlate with merging frequencies.

scholarly journals Triple Galaxies and a Hidden Mass Problem

1990 ◽  
Vol 124 ◽  
pp. 115-127
Author(s):  
I.D. Karachentsev ◽  
V.E. Karachentseva ◽  
V.S. Lebedev
Keyword(s):  
Velocity Dispersion ◽  
Absolute Magnitude ◽  
Mass Excess ◽  
Homogeneous Sample ◽  
Groups Of Galaxies ◽  
Triple Systems ◽  
Crossing Time ◽  
Dynamical Parameters ◽  
Virial Mass ◽  
Harmonic Radius

AbstractWe consider a homogeneous sample of 84 triple systems of galaxies with components brighter than m = 15.7, located in the northern sky and satisfying an isolation criterion with respect to neighboring galaxies in projection. The distributions of basic dynamical parameters for triplets have median values as follows: radial velocity dispersion 133 km/s, mean harmonic radius 63 kpc, absolute magnitude of galaxies MB = —20.38, crossing time τ = 0.04 H−1. For different ways of estimation the median mass-to-luminosity ratio is (20 – 30)f⊙.A comparison of the last value with the ones for single and binary galaxies shows the presence of a virial mass excess for triplets by a factor 4. The mass-to-luminosity ratio is practically uncorrelated with linear size of triplets or with morphological types of their components.We note that a significant part of the virial excess may be explained by the presence of nonisolated triple configurations in the sample, which are produced by debris of more populous groups of galaxies.

scholarly journals The Properties of Isolated Main Galaxies in Sloan Digital Sky Survey Data Release 3 (SDSS DR3)

2006 ◽  
Vol 23 (2) ◽  
pp. 76-81 ◽  
Author(s):  
Xinfa Deng ◽  
Xinsheng Ma ◽  
Chenghong Luo ◽  
Qun Zhang ◽  
Qing-Hua Liao ◽  
...  
Keyword(s):  
Cluster Analysis ◽  
Survey Data ◽  
Sloan Digital Sky Survey ◽  
Early Type ◽  
Double Galaxy ◽  
Main Galaxy ◽  
Sky Survey ◽  
Data Release ◽  
Galaxy Sample

AbstractWe have constructed a Main galaxy subsample of 67777 galaxies with redshifts in the range 0.08 ≤ z ≤ 0.12 from the Sloan Digital Sky Survey Data Release 3. Using cluster analysis, two isolated Main galaxy samples were extracted from this subsample. The two isolated Main galaxy samples identified at different radii have the same properties. Additionally, we find fewer early-type galaxies in isolated Main galaxy samples than in a close double galaxy sample.

Further Investigation of the Effect of Galaxy Interactions on Star Formation

2013 ◽  
Vol 22 (2) ◽  
Author(s):  
Xin-Fa Deng ◽  
Fuyang Zhang
Keyword(s):  
Star Formation ◽  
Survey Data ◽  
Control Sample ◽  
Sloan Digital Sky Survey ◽  
Apparent Magnitude ◽  
Galaxy Interactions ◽  
Main Galaxy ◽  
Sky Survey ◽  
Data Release ◽  
Galaxy Sample

AbstractFrom the apparent magnitude-limited the Main galaxy sample of the Sloan Digital Sky Survey Data Release 7, we construct a paired galaxy sample and a control sample without close companions with the projected separations

scholarly journals Simulations of Compact Groups of Galaxies with Halos

1987 ◽  
Vol 117 ◽  
pp. 281-281
Author(s):  
T. Ishizawa
Keyword(s):  
Velocity Dispersion ◽  
Big Bang ◽  
Compact Groups ◽  
Maximum Expansion ◽  
Groups Of Galaxies ◽  
Elapsed Time ◽  
Self Consistent ◽  
The Big Bang ◽  
Hubble Time

Self-consistent simulations of seven groups are performed from the maximum expansion to the present using Aarseth's N-body code. An initial galaxy consists of 100 stars. Its mass, half-mass radius, and central velocity dispersion are 1, 0.41, and 0.96. Units of mass, length, velocity, and time are 1.4×101 2M⊙, 100 kpc, 245 kms−1 and 4.0×108y. Table 1 gives the elapsed time from the Big Bang to the formation of a multiple merger tm+Tc*/2. For H0=80 kms−1Mpc−1, the Hubble time H0−1=30.6 in our units. Dense groups except B form multiple mergers in a Hubble time.

scholarly journals Compact Groups of Galaxies

1999 ◽  
Vol 186 ◽  
pp. 367-373
Author(s):  
P. Hickson
Keyword(s):  
Galaxy Evolution ◽  
Mass Velocity ◽  
Velocity Dispersion ◽  
Continuous Process ◽  
Physical Nature ◽  
Compact Groups ◽  
Early Type ◽  
Natural Explanation ◽  
Groups Of Galaxies ◽  
Formation And Evolution

This paper reviews some of the outstanding questions concerning compact groups of galaxies. These relate to the physical nature and dynamical status of the groups, their formation and evolution, and their role in galaxy evolution. The picture that emerges is that compact groups are generally physically dense systems, although often contaminated by optical projections. Their evolution is likely a continuous process of infall, interaction and merging. As new galaxies are added, and previous ones merge, the membership of the group evolves. I suggest that while the size of the group changes little, other physical properties such as total mass, gas mass, velocity dispersion, fraction of early-type galaxies increase with time. This picture is at least qualitatively consistent with observations and provides a natural explanation for the strongest correlations found in compact group samples.

scholarly journals The X-Ray Emitting Galaxy Group SHKH 360

1996 ◽  
Vol 171 ◽  
pp. 453-453
Author(s):  
H. Tiersch ◽  
H. Oleak ◽  
D. Stoll ◽  
A.D. Schwope ◽  
S. Neizvestny ◽  
...  
Keyword(s):  
Velocity Dispersion ◽  
Red Shift ◽  
Space Density ◽  
X Ray ◽  
Strongly Interacting ◽  
Crossing Time ◽  
Virial Mass ◽  
Image Position

Shkh 360 has the characteristic signature of a strongly interacting group. Seven galaxies are embedded in a common extended halo and the isophotes indicate clear signs of alignment in B,V, and R. The parameters of the group as the red shift, z, the distance, d, the projected diameter, D, (basing on H = 55 km/s/Mpc), the virial radius, Rvir, the velocity dispersion, σv, the virial mass, the crossing time, τ, and the space density of galaxies, n, are given in the Table.

Dependence of the clustering properties of galaxies on stellar velocity dispersion in the Main galaxy sample of SDSS DR10

2014 ◽  
Vol 352 (2) ◽  
pp. 833-838 ◽  
Author(s):  
Xin-Fa Deng ◽  
Jun Song ◽  
Yi-Qing Chen ◽  
Peng Jiang ◽  
Ying-Ping Ding
Keyword(s):  
Velocity Dispersion ◽  
Main Galaxy ◽  
Stellar Velocity ◽  
Galaxy Sample

scholarly journals Effects of Interactions on Galaxy Properties in the Main Galaxy Sample of SDSS Data Release 5

2008 ◽  
Vol 677 (2) ◽  
pp. 1040-1045 ◽  
Author(s):  
Xin‐Fa Deng ◽  
Ji‐Zhou He ◽  
Peng Jiang ◽  
Jun Song ◽  
Xiao‐Xun Tang
Keyword(s):  
Main Galaxy ◽  
Data Release ◽  
Galaxy Sample

scholarly journals Disentangling the intragroup HI in Compact Groups of galaxies by means of X3D visualization

2016 ◽  
Vol 11 (S321) ◽  
pp. 241-243
Author(s):  
Lourdes Verdes-Montenegro ◽  
Frederic Vogt ◽  
Claire Aubery ◽  
Laetitie Duret ◽  
Julián Garrido ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Compact Groups ◽  
Evolutionary Sequence ◽  
Groups Of Galaxies ◽  
Data Cubes ◽  
Tidal Interactions ◽  
Evolutionary Phase ◽  
Hickson Compact Groups ◽  
Access To Data ◽  
Uncertain Distribution

AbstractAs an extreme kind of environment, Hickson Compact groups (HCGs) have shown to be very complex systems. HI-VLA observations revealed an intrincated network of HI tails and bridges, tracing pre-processing through extreme tidal interactions. We found HCGs to show a large HI deficiency supporting an evolutionary sequence where gas-rich groups transform via tidal interactions and ISM (interstellar medium) stripping into gas-poor systems. We detected as well a diffuse HI component in the groups, increasing with evolutionary phase, although with uncertain distribution. The complex net of detected HI as observed with the VLA seems hence so puzzling as the missing one. In this talk we revisit the existing VLA information on the HI distribution and kinematics of HCGs by means of X3D visualization. X3D constitutes a powerful tool to extract the most from HI data cubes and a mean of simplifying and easing the access to data visualization and publication via three-dimensional (3-D) diagrams.

Environmental Dependence of Different Colors for the Apparent Magnitude-Limited Main Galaxy Sample of the SDSS DR7

2013 ◽  
Vol 22 (2) ◽  
Author(s):  
Xin-Fa Deng ◽  
Cheng-Hong Luo ◽  
Yong Xin ◽  
Ping Wu
Keyword(s):  
Survey Data ◽  
Sloan Digital Sky Survey ◽  
Apparent Magnitude ◽  
Main Galaxy ◽  
Sky Survey ◽  
Data Release ◽  
Galaxy Sample ◽  
Environmental Dependence

AbstractThe apparent magnitude-limited Main galaxy sample of the Sloan Digital Sky Survey Data Release 7 is used to investigate the environmental dependence of

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