scholarly journals Observational Properties of Triple Galaxies

2000 ◽  
Vol 174 ◽  
pp. 1-10
Author(s):  
I. D. Karachentsev
Keyword(s):  
Narrow Range ◽  
Triple Systems ◽  
Galaxy Groups ◽  
Crossing Time ◽  
Local Supercluster ◽  
Virial Mass ◽  
Nearby Galaxies

AbstractThis report presents basic observational parameters for galaxy triplets selected by criterion of their isolation on the sky (=Catalog of Triple Galaxies, Karachentseva et al, 1979). The CTG sample is compared with a sample of wide triple systems from Nearby Galaxies Catalog (Tully, 1988) as well from a new whole-sky catalog of small galaxy groups in the Local Supercluster (Makarov & Karachentsev, 2000). For all the samples their medians of the virial mass-to-luminosity ratio lie in a narrow range, 31 < Mvir/L < 36 (M⊙/L⊙), while the medians of the crossing time occupy a wider range, 0.07 < Tcross < 0.37 (in 1/H units).

scholarly journals A new catalogue of multiple galaxies in the Local Supercluster

2000 ◽  
Vol 174 ◽  
pp. 40-45
Author(s):  
D. I. Makarov ◽  
I. D. Karachentsev
Keyword(s):  
New Approach ◽  
Galaxy Groups ◽  
Closed Orbits ◽  
Crossing Time ◽  
Local Supercluster ◽  
Virial Mass ◽  
Nearby Galaxies ◽  
The Individual ◽  
Group Member ◽  
Harmonic Radius

AbstractA new approach is suggested which makes use of the individual properties of galaxies, for the identification of small galaxy groups in the Local Supercluster. The criterion is based on the assumption of closed orbits of the companions around the dominating group member within a zero velocity sphere.The criterion is applied to a sample of 6321 nearby galaxies with radial velocities V0 ≤ 3000 km s−1. These 3472 galaxies have been assigned to 839 groups that include 55% of the sample considered. For the groups identified by the new algorithm (with k ≥ 5 members) the median velocity dispersion is 86 km s−1, the median harmonic radius is 247 kpc, the median crossing time is 0.08(1/H), and the median virial-mass-to-light ratio is 56 M⊙/L⊙.

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 Electromagnetic transients and gravitational waves from white dwarf disruptions by stellar black holes in triple systems

2020 ◽  
Vol 495 (1) ◽  
pp. 1061-1072
Author(s):  
Giacomo Fragione ◽  
Brian D Metzger ◽  
Rosalba Perna ◽  
Nathan W C Leigh ◽  
Bence Kocsis
Keyword(s):  
White Dwarf ◽  
Gamma Ray ◽  
High Energy ◽  
Stellar Mass ◽  
Compact Objects ◽  
Electromagnetic Transients ◽  
Tidal Disruption ◽  
Single Star ◽  
Triple Systems ◽  
Nearby Galaxies

ABSTRACT Mergers of binaries comprising compact objects can give rise to explosive transient events, heralding the birth of exotic objects that cannot be formed through single-star evolution. Using a large number of direct N-body simulations, we explore the possibility that a white dwarf (WD) is dynamically driven to tidal disruption by a stellar-mass black hole (BH) as a consequence of the joint effects of gravitational wave (GW) emission and Lidov–Kozai oscillations imposed by the tidal field of an outer tertiary companion orbiting the inner BH–WD binary. We explore the sensitivity of our results to the distributions of natal kick velocities imparted to the BH and WD upon formation, adiabatic mass loss, semimajor axes and eccentricities of the triples, and stellar-mass ratios. We find rates of WD–tidal disruption events (TDEs) in the range 1.2 × 10−3 − 1.4 Gpc−3 yr−1 for z ≤ 0.1, rarer than stellar TDEs in triples by a factor of ∼3–30. The uncertainty in the TDE rates may be greatly reduced in the future using GW observations of Galactic binaries and triples with LISA. WD–TDEs may give rise to high-energy X-ray or gamma-ray transients of duration similar to long gamma-ray bursts but lacking the signatures of a core-collapse supernova, while being accompanied by a supernova-like optical transient that lasts for only days. WD–BH and WD–NS binaries will also emit GWs in the LISA band before the TDE. The discovery and identification of triple-induced WD–TDE events by future time domain surveys and/or GWs could enable the study of the demographics of BHs in nearby galaxies.

scholarly journals The Orientation of Galaxies in Nearby Galaxy Groups

2004 ◽  
Vol 217 ◽  
pp. 116-117
Author(s):  
P. Flin ◽  
M. Biernacka ◽  
J. Krywult
Keyword(s):  
Statistical Analysis ◽  
Milky Way ◽  
Random Distribution ◽  
Local Group ◽  
Dwarf Galaxies ◽  
Nearby Galaxy ◽  
Groups Of Galaxies ◽  
Galaxy Groups ◽  
Isotropic Distribution ◽  
Local Supercluster

The statistical analysis of six nearby groups of galaxies, connected with the Milky Way, M31, M81, M101, NGC5128 and NGC5236 shows an isotropic distribution of galaxy planes, similarly to galaxies within the Local Group. Also planes of galaxies in the nearby (Vr < 500 km s−1) region of the Local Supercluster exhibit random distribution, disregarding their membership to groups. The result shows that strong environmental effects observed among dwarf galaxies do not change generally random distribution of galaxy planes in this region.

scholarly journals Some Properties of Galaxy Structures

2011 ◽  
Vol 20 (2) ◽  
Author(s):  
Piotr Flin ◽  
Monika Biernacka ◽  
Włodzimierz Godłowski ◽  
Elena Panko ◽  
Paulina Piwowarska
Keyword(s):  
Spatial Orientation ◽  
Velocity Dispersion ◽  
Statistical Tests ◽  
Scale Up ◽  
Morphological Type ◽  
Strongly Correlated ◽  
Galaxy Groups ◽  
Abell Clusters ◽  
Local Supercluster ◽  
The Galaxy

AbstractWe analysed some properties of galaxies structures based on the PF catalog of galaxy structures (Panko & Flin 2006) and the Tully NBG catalog (Tully 1988). At first, we analyzed the orientation of galaxies in the 247 optically selected rich Abell clusters, having at least 100 members. The distribution of the position angles of galaxies as well as of two angles describing spatial orientation of the galaxy planes were tested for isotropy, applying three statistical tests. We found the relation between the anisotropy and the cluster richness. The relation between the galaxy alignment and the Bautz-Morgan morphological type of the parent cluster is not present. A statistically marginal relation between the velocity dispersion and cluster richness is observed. We also analyzed ellipticities for 6188 low redshift (z < 0.18) poor and rich galaxy structures which have been examined along with their evolution. Finally, we analyzed the Binggeli effect and found that the orientation of galaxy groups in the Local Supercluster (LSC), is strongly correlated with the distribution of neighbouring groups in the scale up to about 20 Mpc. Analysis of galaxy structures from the PF catalog shows quite different situation - the efect is observed only for more elongated structures (e ≤ 0.3). The effect is present in a distance range of about 60 h

scholarly journals Structure and kinematics of the Bootes filament

2014 ◽  
Vol 11 (S308) ◽  
pp. 187-192
Author(s):  
O. Nasonova ◽  
I. Karachentsev ◽  
V. Karachentseva
Keyword(s):  
Dark Matter ◽  
Stellar Mass ◽  
Average Density ◽  
Virgo Cluster ◽  
Galaxy Groups ◽  
Peculiar Velocities ◽  
Galaxy Distribution ◽  
The Galaxy ◽  
Virial Mass ◽  
Individual Distance

AbstractBootes filament of galaxies is a dispersed chain of groups residing on sky between the Local Void and the Virgo cluster. We consider a sample of 361 galaxies inside the sky area of RA = 13h0...18h.5 and Dec = .5°... + 10° with radial velocities VLG < 2000 km/s to clarify its structure and kinematics. In this region, 161 galaxies have individual distance estimates. We use these data to draw the Hubble relation for galaxy groups, pairs as well as the field galaxies, and to examine the galaxy distribution on peculiar velocities. Our analysis exposes the known Virgo-centric infall at RA < 14h and some signs of outflow from the Local Void at RA > 17h. According to the galaxy grouping criterion, this complex contains the members of 13 groups, 11 pairs and 140 field galaxies. The most prominent group is dominated by NGC 5846. The Bootes filament contains the total stellar mass of 2.7 ×1012M⊙ and the total virial mass of 9.07×1013M⊙, having the average density of dark matter to be Ωm = 0.09, i.e. a factor three lower than the global cosmic value.

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.

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 Dark Matter in Groups and Clusters of Galaxies

1995 ◽  
Vol 164 ◽  
pp. 454-454
Author(s):  
M. Kalinkov ◽  
I. Kuneva ◽  
I. Valtchanov
Keyword(s):  
Line Of Sight ◽  
Clusters Of Galaxies ◽  
Dynamical Models ◽  
Dynamical Characteristics ◽  
Velocity Statistics ◽  
Total Luminosity ◽  
Crossing Time ◽  
Pair Separation ◽  
Virial Mass ◽  
Harmonic Radius

Samples of groups, clusters and superclusters of galaxies have been collected from existing catalogs. The group sample consisted of 70 systems, the list of clusters contains 50 systems, and there are five superclusters. Kinematical and dynamical characteristics are obtained — elongation (along the line of sight, RA and Dec), velocity statistics, total luminosity, harmonic radius, mean pair separation, crossing time, virial mass … We have compared some of the observational features with dynamical models of groups, clusters and superclusters. Aarseth's (1985) code is used.

scholarly journals Detecting galaxy–filament alignments in the Sloan Digital Sky Survey III

2019 ◽  
Vol 485 (2) ◽  
pp. 2492-2504 ◽  
Author(s):  
Yen-Chi Chen ◽  
Shirley Ho ◽  
Jonathan Blazek ◽  
Siyu He ◽  
Rachel Mandelbaum ◽  
...  
Keyword(s):  
Narrow Range ◽  
Stellar Mass ◽  
Sloan Digital Sky Survey ◽  
Nearby Galaxy ◽  
Matter Distribution ◽  
Direction Parallel ◽  
Significant Alignment ◽  
Sky Survey ◽  
Nearby Galaxies ◽  
Web Reconstruction

Abstract Previous studies have shown the filamentary structures in the cosmic web influence the alignments of nearby galaxies. We study this effect in the LOWZ sample of the Sloan Digital Sky Survey using the ‘Cosmic Web Reconstruction' filament catalogue. We find that LOWZ galaxies exhibit a small but statistically significant alignment in the direction parallel to the orientation of nearby filaments. This effect is detectable even in the absence of nearby galaxy clusters, which suggests it is an effect from the matter distribution in the filament. A non-parametric regression model suggests that the alignment effect with filaments extends over separations of 30–40 Mpc. We find that galaxies that are bright and early-forming align more strongly with the directions of nearby filaments than those that are faint and late-forming; however, trends with stellar mass are less statistically significant, within the narrow range of stellar mass of this sample.

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