Solar Motion with Respect to the Nearest Galaxies

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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Some Properties of Galaxy Structures

Open Astronomy ◽

10.1515/astro-2017-0289 ◽

2011 ◽

Vol 20 (2) ◽

Cited By ~ 1

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

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Constrained Simulations of the Local Universe

Proceedings of the International Astronomical Union ◽

10.1017/s1743921307014445 ◽

2007 ◽

Vol 3 (S244) ◽

pp. 395-396

Author(s):

G. Yepes ◽

L. Martinez-Vaquero ◽

Y. Hoffman ◽

S. Gottlöber ◽

A. Klypin

Keyword(s):

Dark Matter ◽

Galaxy Formation ◽

Local Group ◽

Initial Density ◽

High Accuracy ◽

Density Field ◽

Local Universe ◽

Local Mass ◽

Local Supercluster ◽

The Galaxy

AbstractWe have studied the formation of the Local Universe using constrained cosmological simulations. To this end we use the observed local mass and velocity distributions to generate the initial density field. A variety of N-body simulations with different box sizes and resolutions have been done so far. The largest structures, such as Coma, Virgo and the Local Supercluster are reproduced with high accuracy. We have also been able to obtain a representation of the Local Group with unprecedented accuracy and resolution. From these simulations we are studying in detail the dynamics of the dark matter in our neighborhood. The next step will be to include baryons and study in detail the galaxy formation in our local universe.

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The Magellanic Stream: Observational Considerations

Symposium - International Astronomical Union ◽

10.1017/s0074180900015072 ◽

1979 ◽

Vol 84 ◽

pp. 547-556 ◽

Cited By ~ 4

Author(s):

D. S. Mathewson ◽

V. L. Ford ◽

M. P. Schwarz ◽

J. D. Murray

Keyword(s):

Local Group ◽

Galactic Center ◽

Neutral Hydrogen ◽

Great Circle ◽

Magellanic Clouds ◽

Systematic Variation ◽

The Sun ◽

The South ◽

The Galaxy ◽

Magellanic Stream

The Magellanic Stream is an arc of neutral hydrogen which nearly follows a great circle and which contains the Magellanic Clouds - hence its name (Mathewson, Cleary and Murray 1974). This great circle passes within a few degrees of the south galactic pole and lies close to the supergalactic plane. Mathewson and Schwarz (1976) argued that this indicates that the Magellanic Stream and Magellanic Clouds are not bound to the Galaxy. To reinforce this argument, they pointed out that around the supergalactic plane there is a similar systematic variation in the velocities of the Local Group and those of the Stream which may be due to the reflection of the motion of the galactic center if the velocity of rotatior of the Sun is 225 km s−1; if it is 290 km s−1 then the grounds for this argument would disappear.

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The Magellanic Stream: theoretical considerations

Symposium - International Astronomical Union ◽

10.1017/s0074180900015084 ◽

1979 ◽

Vol 84 ◽

pp. 557-566 ◽

Cited By ~ 1

Author(s):

M. Fujimoto

Keyword(s):

Local Group ◽

Galactic Disk ◽

Magellanic Clouds ◽

Particle Simulation ◽

The Past ◽

Local Supercluster ◽

New Models ◽

The Galaxy ◽

Magellanic Stream ◽

Theoretical Considerations

The tidal and the primordial theories for the Magellanic Stream are examined in a frame of test-particle simulation for the interacting triple system of the Galaxy, the Large and Small Magellanic Clouds (LMC and SMC). Difficulties of the radial velocity of the Stream still beset these two theories. Several new models for the Stream and the Clouds are briefly discussed in relation to the bending of the galactic disk, the past binary orbits of the LMC and SMC and also the Local Group and the Local Supercluster of galaxies.

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V. Kinematics

Transactions of the International Astronomical Union ◽

10.1017/s0251107x00006477 ◽

1985 ◽

Vol 19 (1) ◽

pp. 416-423

Keyword(s):

Velocity Dispersion ◽

Galactic Center ◽

Proper Motions ◽

Giant Stars ◽

The Core ◽

Ir Stars ◽

The Galaxy ◽

Red Giant ◽

M Stars ◽

Absolute Coordinates

Wollman et al. (32.155.001) present high-resolution 2 um spectra of three red giant stars in the core of the Galaxy. The properties of 0H/IR stars were studied by Baud et al. (29.131.023), Olnon et al. (29.155.032), Habing et al. (34.155.048), and Baud (34.155.042). Vanderspeck and Ricker (34.041.001) determined absolute coordinates for 19 stars within 2’ of the galactic center for epoch 1958.3 and 1976.3 and calculated their proper motions. Mould (33.155.013) obtained the radial-velocity dispersion for M stars in the nuclear bulge.

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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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A Statistical Estimation of the Occurrence of Extraterrestrial Intelligence in the Milky Way Galaxy

Galaxies ◽

10.3390/galaxies9010005 ◽

2021 ◽

Vol 9 (1) ◽

pp. 5

Author(s):

Xiang Cai ◽

Jonathan H. Jiang ◽

Kristen A. Fahy ◽

Yuk L. Yung

Keyword(s):

Statistical Estimation ◽

Milky Way ◽

Galactic Center ◽

Model Simulation ◽

Temporal Variations ◽

Extraterrestrial Intelligence ◽

Milky Way Galaxy ◽

The Galaxy ◽

Peak Location ◽

Intelligent Life

In the field of astrobiology, the precise location, prevalence, and age of potential extraterrestrial intelligence (ETI) have not been explicitly explored. Here, we address these inquiries using an empirical galactic simulation model to analyze the spatial–temporal variations and the prevalence of potential ETI within the Galaxy. This model estimates the occurrence of ETI, providing guidance on where to look for intelligent life in the Search for ETI (SETI) with a set of criteria, including well-established astrophysical properties of the Milky Way. Further, typically overlooked factors such as the process of abiogenesis, different evolutionary timescales, and potential self-annihilation are incorporated to explore the growth propensity of ETI. We examine three major parameters: (1) the likelihood rate of abiogenesis (λA); (2) evolutionary timescales (Tevo); and (3) probability of self-annihilation of complex life (Pann). We found Pann to be the most influential parameter determining the quantity and age of galactic intelligent life. Our model simulation also identified a peak location for ETI at an annular region approximately 4 kpc from the galactic center around 8 billion years (Gyrs), with complex life decreasing temporally and spatially from the peak point, asserting a high likelihood of intelligent life in the galactic inner disk. The simulated age distributions also suggest that most of the intelligent life in our galaxy are young, thus making observation or detection difficult.

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Gamma-Ray Imaging of the Galactic Center Region

Symposium - International Astronomical Union ◽

10.1017/s007418090018708x ◽

1989 ◽

Vol 136 ◽

pp. 581-585

Author(s):

W. R. Cook ◽

D. M. Palmer ◽

T. A. Prince ◽

S. M. Schindler ◽

C. H. Starr ◽

...

Keyword(s):

Gamma Ray ◽

Galactic Center ◽

Coded Aperture ◽

Center Region ◽

Gamma Ray Imaging ◽

The Galaxy ◽

Γ Ray ◽

Luminous Objects

The Caltech imaging γ-ray telescope was launched by balloon from Alice Springs, NT, Australia and performed observations of the galactic center during the period 12.62 to 13.00 April 1988 UT. The first coded-aperture images of the galactic center region at energies above 30 keV show a single strong γ-ray source which is located 0.7±0.1° from the galactic nucleus and is tentatively identified as 1E1740.7-2942. If the source is at the distance of the galactic center, it is one of the most luminous objects in the galaxy at energies from 35 to 200 keV.

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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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