Some Properties of Galaxy Structures

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

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The Orientation of Galaxies in Superclusters

Symposium - International Astronomical Union ◽

10.1017/s0074180900136095 ◽

1988 ◽

Vol 130 ◽

pp. 239-241

Author(s):

Piotr Flin

Keyword(s):

Positive Result ◽

Spatial Orientation ◽

Axial Ratio ◽

Major Axis ◽

Position Angle ◽

Main Plane ◽

Local Supercluster ◽

The Galaxy ◽

Spatial Geometry

The alignment of galaxies with the main plane of supercluster can contribute to recovering information on the structure origin. The positive result of the preliminary search for galaxy alignment in the Local Supercluster /Flin and Godlowski 1986, hereafter FG/ have stimulated further studies. Following Jaaniste and Saar /1977/, the both parameters, the position angle of the galaxy major axis p and the axial ratio b/a of the galaxy image, were used for the better determination of the actual spatial orientation of the galaxy disc. This approach also permit to consider “face-on” objects, whose discounting leads to obvious incompleteness of the analysed data. Each galaxy has two possible orientations and both were taken into account during calculations. The analysis is perfomed by transforming position angle p and coordinates α, δ of galaxies expressed in the equatorial coordinates into coordinate system connected with each parent supercluster separately, which gives parameters P, l and b respectively. The main supercluster plane should be determined, which resticts the present study to the three superclusters with a known spatial geometry, i.e. LSC /Tully 1982/, Perseus and Coma/A1367 /Chincarini et al. 1983/.

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Galaxy Groups: Morphological Segregation Between Spirals

Symposium - International Astronomical Union ◽

10.1017/s0074180900136599 ◽

1988 ◽

Vol 130 ◽

pp. 530-530

Author(s):

G. Giuricin ◽

F. Mardirossian ◽

M. Mezzetti ◽

A. Pisani ◽

M. Ramella

Keyword(s):

Morphological Type ◽

Pairwise Distance ◽

Early Type ◽

Groups Of Galaxies ◽

Galaxy Groups ◽

The Family ◽

The Galaxy ◽

The Mean ◽

Type Code

We have considered the sample of groups of galaxies identified by M. J. Geller and J. P. Huchra (1983, Astrophys. J. Suppl. 52, 61), omitting the groups which are part of well-known clusters or those which are probably affected by the presence of interlopers. We have searched for possible morphological segregation among spirals in galaxy groups considering the mean-pairwise distance of the members of the galaxy system and the mean distance of the members from the center of the system. All the distances are normalized to the mean-pairwise distance (MPD) and to the mean distance from the center (CD), respectively, of all the members of the groups considered. We divided the family of the spirals (plus irregulars) into two subfamilies (S′ and S″); we included in S′ the early-type spirals (with morphological type code 0≤T≤2) and in S″ the galaxies of the late morphological types (with T ≥ 3). The median values of the ratios MPD(S′)/MPD, MPD(S″)/MPD, CD(S′)/CD, CD(S″)/CD are 0.86, 1.17, 0.95, 1.08, respectively.

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Solar Motion with Respect to the Nearest Galaxies

International Astronomical Union Colloquium ◽

10.1017/s0252921100053562 ◽

1977 ◽

Vol 37 ◽

pp. 149-153

Author(s):

G. de Vaucouleurs ◽

W.L. Peters ◽

H.G. Corwin

Keyword(s):

Velocity Dispersion ◽

Local Group ◽

Galactic Center ◽

Intergalactic Gas ◽

Residual Velocity ◽

First Order ◽

Order Expansion ◽

Solar Motion ◽

Local Supercluster ◽

The Galaxy

AbstractSolutions for solar motion with respect to 12 classical members of the restricted Local Group and 9 additional proposed members of an extended Local Group, all within 2 Mpc, suggest that the Local Group – both restricted and extended – is expanding at a rate, H* = 47 ± 12 ou 57 ± 11 km s-1 Mpc-1, which is significantly lower than its free-space (asymptotic) value Ho ≃, 90 km s-1 Mpc-1, as required by the rotating-expanding model of the Local supercluster. The differential rotation effects predicted by the model are detectable in the velocity residuals with correct phase L*o = 87° and amplitude A* = 30 to 40 km s-1 Mpc-1 in the first-order expansion.V = H*r + V⊙ cos A + A* r sin 2(L-L*o) cos2BThe solar motion with respect to the velocity centroid of the Local Group is V⊙ = 340 ± 18 km s-1 toward the apex 1 = 105° ± 5°, b = -11° ± 3°. With the conventional values of the solar motion within the Galaxy the apex of the galactic center in the Local Group is at supergalactic coordinates L = 325° ± 11°, B = -12° ± 11° with a velocity VG = 140 + 25 km s-1.The residual velocity dispersion σ = 40 to 50 km s-1 implies a virial theorem mass VT ≃ 9 x 1011⊙ not significantly in excess of that which can be accounted for by the member galaxies and intergalactic gas clouds.

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Galaxy Formation: Some Comparisons between Theory and Observation

Symposium - International Astronomical Union ◽

10.1017/s0074180900033350 ◽

1983 ◽

Vol 100 ◽

pp. 391-399 ◽

Cited By ~ 1

Author(s):

S. Michael Fall

Keyword(s):

Galaxy Formation ◽

Total Mass ◽

Virial Theorem ◽

Velocity Dispersion ◽

Rotation Velocity ◽

Morphological Type ◽

Fundamental Parameter ◽

Mass Ratio ◽

First Approximation ◽

Type Form

Before theoretical ideas in this subject can be compared with observational data, it is necessary to consider the properties of galaxies that are likely to be relics of their formation. Most astronomers would agree that the list of important parameters should be headed by the total mass M, energy E and angular momentum J. Next on the list should probably be the relative contributions to these quantities from the disc and bulge components of galaxies and denoted D/B for the mass ratio. They can be estimated from the median (i.e. half-mass) radius R, velocity dispersion σ and rotation velocity v of each component, either through the virial theorem or through the luminosity L and an assumed value of M/L. As a first approximation, it is reasonable to suppose that galaxies of a given disc-to-bulge ratio or morphological type form a sequence with mass as the fundamental parameter. The comparison of theory with data is further simplified by considering the extreme cases of ellipticals, with D/B << 1, and late-type spirals, with D/B >> 1. The approach outlined below is to explore the consequences of relaxing in succession the constraints that E, J and M be conserved during the collapse of proto-galaxies. In this article I concentrate on theories that are based on some form of hierarchical clustering because the pancake and related theories are not yet refined enough for a detailed confrontation with observations.

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Investigating the properties of a galaxy group at z = 0.6

Proceedings of the International Astronomical Union ◽

10.1017/s1743921320001945 ◽

2020 ◽

Vol 15 (S359) ◽

pp. 188-189

Author(s):

Daniela Hiromi Okido ◽

Cristina Furlanetto ◽

Marina Trevisan ◽

Mônica Tergolina

Keyword(s):

Large Scale ◽

The Other ◽

Numerical Density ◽

Spectroscopy Data ◽

Stellar Kinematics ◽

Galaxy Groups ◽

The Galaxy ◽

The Difference ◽

The Impact ◽

The Universe

AbstractGalaxy groups offer an important perspective on how the large-scale structure of the Universe has formed and evolved, being great laboratories to study the impact of the environment on the evolution of galaxies. We aim to investigate the properties of a galaxy group that is gravitationally lensing HELMS18, a submillimeter galaxy at z = 2.39. We obtained multi-object spectroscopy data using Gemini-GMOS to investigate the stellar kinematics of the central galaxies, determine its members and obtain the mass, radius and the numerical density profile of this group. Our final goal is to build a complete description of this galaxy group. In this work we present an analysis of its two central galaxies: one is an active galaxy with z = 0.59852 ± 0.00007, while the other is a passive galaxy with z = 0.6027 ± 0.0002. Furthermore, the difference between the redshifts obtained using emission and absorption lines indicates an outflow of gas with velocity v = 278.0 ± 34.3 km/s relative to the galaxy.

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A new catalogue of multiple galaxies in the Local Supercluster

International Astronomical Union Colloquium ◽

10.1017/s0252921100054725 ◽

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⊙.

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Anisotropy in ω Centauri and 47 Tucanae

Symposium - International Astronomical Union ◽

10.1017/s0074180900043503 ◽

1988 ◽

Vol 126 ◽

pp. 663-664

Author(s):

G. Meylan

Keyword(s):

Globular Clusters ◽

Velocity Dispersion ◽

Dynamical Models ◽

Comprehensive Description ◽

Great Opportunity ◽

The Galaxy

The southern sky gives us the great opportunity to observe two among the brightest and nearest globular clusters of the Galaxy: ω Cen and 47 Tuc. For these giant clusters, we present the comparison between observations and King-Michie multi-mass dynamical models with anisotropy in the velocity dispersion. A more comprehensive description of this work is to be published (Meylan 1986a,b).

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Supermassive Black Hole feedback in early type galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921320004081 ◽

2020 ◽

Vol 15 (S359) ◽

pp. 119-125

Author(s):

W. Forman ◽

C. Jones ◽

A. Bogdan ◽

R. Kraft ◽

E. Churazov ◽

...

Keyword(s):

Dark Matter Halo ◽

Scaling Relations ◽

Radio Sources ◽

Early Type ◽

X Ray ◽

Galaxy Groups ◽

Sufficient Energy ◽

The Galaxy ◽

Simple Scaling ◽

Halo Masses

AbstractOptically luminous early type galaxies host X-ray luminous, hot atmospheres. These hot atmospheres, which we refer to as coronae, undergo the same cooling and feedback processes as are commonly found in their more massive cousins, the gas rich atmospheres of galaxy groups and galaxy clusters. In particular, the hot coronae around galaxies radiatively cool and show cavities in X-ray images that are filled with relativistic plasma originating from jets powered by supermassive black holes (SMBH) at the galaxy centers. We discuss the SMBH feedback using an X-ray survey of early type galaxies carried out using Chandra X-ray Observatory observations. Early type galaxies with coronae very commonly have weak X-ray active nuclei and have associated radio sources. Based on the enthalpy of observed cavities in the coronae, there is sufficient energy to “balance” the observed radiative cooling. There are a very few remarkable examples of optically faint galaxies that are 1) unusually X-ray luminous, 2) have large dark matter halo masses, and 3) have large SMBHs (e.g., NGC4342 and NGC4291). These properties suggest that, in some galaxies, star formation may have been truncated at early times, breaking the simple scaling relations.

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Poor Groups Around Strong Gravitational Lenses

Proceedings of the International Astronomical Union ◽

10.1017/s174392130600634x ◽

2006 ◽

Vol 2 (S235) ◽

pp. 230-230

Author(s):

Ivelina Momcheva ◽

Kurtis Williams ◽

Ann Zabludoff ◽

Charles Keeton

Keyword(s):

Galaxy Evolution ◽

Velocity Dispersion ◽

Gravitational Lenses ◽

Local Universe ◽

Groups Of Galaxies ◽

Hot Gas ◽

Gas Kinematics ◽

The Galaxy ◽

Group Centroid ◽

Group Galaxy

AbstractPoor groups are common and interactive environments for galaxies, and thus are important laboratories for studying galaxy evolution. Unfortunately, little is known about groups at z ≥ 0.1, because of the difficulty in identifying them in the first place. Here we present results from our ongoing survey of the environments of strong gravitational lenses, in which we have so far discovered six distant (z ≥ 0.5) groups of galaxies. As in the local Universe, the highest velocity dispersion groups contain a brightest member spatially coincident with the group centroid, whereas lower-dispersion groups tend to have an offset brightest group galaxy. This suggests that higher-dispersion groups are more dynamically relaxed than lower-dispersion groups and that at least some evolved groups exist by z ~ 0.5. We also compare the galaxy and hot gas kinematics with those of similarly distant clusters and of nearby groups.

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