Kinematics and the Galactic Potential

The analysis of stellar kinematics and the Galactic potential is linked to the study of the spatial distribution of stars in the Galaxy since they are related through the Boltzmann and Poisson equations. Measuring all the visible density and mass distribution from general star counts and the gas cloud density gives only a small fraction of the total amount of the dynamical mass that is deduced from the kinematics of the galactic constituents. As in many spiral galaxies, most of the Galactic mass is unseen and unknown.

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Theoretical Considerations on the Dynamics of Normal Galactic Nuclei

Highlights of Astronomy ◽

10.1017/s1539299600003920 ◽

1980 ◽

Vol 5 ◽

pp. 197-204

Author(s):

Robert H. Sanders

Keyword(s):

Spatial Distribution ◽

Gravitational Field ◽

Mass Distribution ◽

Rotation Curve ◽

Spiral Galaxies ◽

Neutral Hydrogen ◽

Galactic Nuclei ◽

The Galaxy ◽

Theoretical Considerations ◽

Normal Spiral

I want to discuss the origin of non-circular gas motions observed in the nuclei of normal spiral galaxies and the possibility that recurring violent activity in normal nuclei excites such motion. But first, let us review several basic aspects of the nearest normal galactic nucleus — the nucleus of our own Galaxy.The rotation curve as observed in the 21-cm line of neutral hydrogen gives some indication of the form of the gravitational field in the central region of the Galaxy. Figure 1 is a smooth fit to the rotation curve in the inner few kiloparsecs (solid line) taken essentially from the data of Rougoor and Oort (1960) and Simonson and Mader (1973). This rotation curve, within 1 kpc of the centre, is completely accounted for by the mass distribution implied by the extended 2.2-μ emission (Becklin and Neugebauer 1968, Oort 1971). Moreover, there is little doubt that this centrally condensed mass distribution should be identified with the bulge or spheroidal component of the Galaxy, because the spatial distribution of the 2.2-μ intensity is practically identical to the distribution of visible starlight in the bulge of M31 (Sandage, Becklin, and Neugebauer 1969). The conclusion is that the bulge overwhelmingly dominates the gravitational field inside of 1 kpc.

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Rapid evolution and transformation into quiescence?: ALMA view on z > 6 low-luminosity quasars

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319009487 ◽

2019 ◽

Vol 15 (S352) ◽

pp. 139-143

Author(s):

Takuma Izumi ◽

Masafusa Onoue ◽

Yoshiki Matsuoka ◽

Tohru Nagao ◽

Michael A. Strauss ◽

...

Keyword(s):

Black Holes ◽

Mass Distribution ◽

Rapid Evolution ◽

Far Infrared ◽

Significant Fraction ◽

Host Galaxies ◽

Dynamical Mass ◽

The Galaxy ◽

Order Of Magnitude ◽

Wide Scatter

AbstractWe present ALMA [CII] line and far-infrared (FIR) continuum observations of seven z > 6 low-luminosity quasars (M1450 > −25 mag) discovered by our on-going Subaru Hyper Suprime-Cam survey. The [CII] line was detected in all targets with luminosities of ∼(2−10) × 108 L⊙, about one order of magnitude smaller than optically luminous quasars. Also found was a wide scatter of FIR continuum luminosity, ranging from LFIR < 1011L⊙ to ∼2 × 1012L⊙. With the [CII]-based dynamical mass, we suggest that a significant fraction of low-luminosity quasars are located on or even below the local Magorrian relation, particularly at the massive end of the galaxy mass distribution. This is a clear contrast to the previous finding that luminous quasars tend to have overmassive black holes relative to the relation. Our result is expected to show a less-biased nature of the early co-evolution of black holes and their host galaxies.

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Enhanced cluster lensing models with measured galaxy kinematics

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935974 ◽

2019 ◽

Vol 631 ◽

pp. A130 ◽

Cited By ~ 8

Author(s):

P. Bergamini ◽

P. Rosati ◽

A. Mercurio ◽

C. Grillo ◽

G. B. Caminha ◽

...

Keyword(s):

Mass Distribution ◽

Velocity Dispersion ◽

Stellar Kinematics ◽

Multiple Images ◽

Effective Velocity ◽

Strong Lensing ◽

The Galaxy ◽

Galaxy Kinematics ◽

Halo Masses

We present an improved determination of the total mass distribution of three massive clusters from the Cluster Lensing and Supernova Survey with Hubble and Hubble Frontier Fields, MACS J1206.2−0847 (z = 0.44), MACS J0416.1−2403 (z = 0.40), Abell S1063 (z = 0.35). We specifically reconstructed the sub-halo mass component with robust stellar kinematics information of cluster galaxies, in combination with precise strong lensing models based on large samples of spectroscopically identified multiple images. We used integral-field spectroscopy in the cluster cores, from the Multi Unit Spectroscopic Explorer on the Very Large Telescope, to measure the stellar velocity dispersion, σ, of 40−60 member galaxies per cluster, covering four to five magnitudes to mF160W ≃ 21.5. We verified the robustness and quantified the accuracy of the velocity dispersion measurements with extensive spectral simulations. With these data, we determined the normalization and slope of the galaxy L–σ Faber–Jackson relation in each cluster and used these parameters as a prior for the scaling relations of the sub-halo population in the mass distribution modeling. When compared to our previous lens models, the inclusion of member galaxies’ kinematics provides a similar precision in reproducing the positions of the multiple images. However, the inherent degeneracy between the central effective velocity dispersion, σ0, and truncation radius, rcut, of sub-halos is strongly reduced, thus significantly alleviating possible systematics in the measurements of sub-halo masses. The three independent determinations of the σ0 − rcut scaling relation in each cluster are found to be fully consistent, enabling a statistical determination of sub-halo sizes as a function of σ0, or halo masses. Finally, we derived the galaxy central velocity dispersion functions of the three clusters projected within 16% of their virial radius, finding that they are well in agreement with each other. We argue that such a methodology, when applied to high-quality kinematics and strong lensing data, allows the sub-halo mass functions to be determined and compared with those obtained from cosmological simulations.

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The Mass Distribution of the Milky Way Deduced from Globular Cluster Dynamics

Symposium - International Astronomical Union ◽

10.1017/s0074180900230593 ◽

1996 ◽

Vol 169 ◽

pp. 697-702 ◽

Cited By ~ 2

Author(s):

B. Dauphole ◽

J. Colin ◽

M. Geffert ◽

M. Odenkirchen ◽

H.-J. Tucholke

Keyword(s):

Spatial Distribution ◽

Mass Distribution ◽

Globular Cluster ◽

Total Mass ◽

Globular Clusters ◽

Large Scale ◽

Milky Way ◽

Proper Motions ◽

Orbital Parameters ◽

Galactic Potential

We present here a new analytical Galactic potential. We used the constraint of galactic globular cluster dynamics compared to their spatial distribution. This was done with the help of the globular clusters' proper motions. The result for the clusters dynamics show a better agreement between orbital parameters and statistical distribution of the studied globular clusters than in previous published potentials. The globular cluster dynamics constrain the mass distribution on a large scale, until 40 kpc from the centre. In this model, the total mass for the Milky Way is 7.9 1011 M⊙.

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Supernovae and Molecular Clouds in Spiral Galaxies

Symposium - International Astronomical Union ◽

10.1017/s0074180900221566 ◽

2001 ◽

Vol 205 ◽

pp. 392-393

Author(s):

Guo-Xuan Song

Keyword(s):

Spatial Distribution ◽

Molecular Clouds ◽

Supernova Remnants ◽

Spiral Galaxies ◽

Inelastic Collisions ◽

Spiral Arms ◽

The Galaxy ◽

Random Distributions

We report N-body simulations of the birthrate and distribution of supernovae in spiral galaxies. The simulations assume that stars form in GMCs with mass greater than 105M⊙ and that a Miller-Scalo IMF results. We assume that the resulting supernovae disrupt the GMC into smaller clouds; these clouds aggregrate to form new GMCs via inelastic collisions. Imposing a spiral potential, we find that supernovae form throughout the disk, but concentrated in the spiral arms. Using conditions appropriate for the Galaxy, a set of simulations with different initial random distributions of molecular clouds predicts 755τ5 supernova remnants (SNR) should exist in the Galaxy (where τ5 is the ratio of the lifetimes of SNRs to 105 yr). The predicted number of remnants and their spatial distribution can be compared to observations.

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When the Largest Spiral is Formed

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313001543 ◽

2012 ◽

Vol 8 (S292) ◽

pp. 328-328

Author(s):

Rafael T. Eufrasio ◽

Duília F. de Mello ◽

Fernanda Urrutia-Viscarra ◽

Claudia Mendes de Oliveira ◽

Eli Dwek

Keyword(s):

Spatial Distribution ◽

Star Formation ◽

Spatial Correlation ◽

Spiral Galaxy ◽

Stellar Population ◽

Spiral Galaxies ◽

Dwarf Galaxy ◽

Archival Data ◽

Physical Size ◽

The Galaxy

AbstractWe used UV-to-IR archival data to investigate the nature of the giant spiral galaxy, NGC 6872, 65 Mpc away. It belongs to the southern Pavo group and is interacting with a small lenticular galaxy, IC4970. GALEX UV images show a very large part of the galaxy not seen before, making it one of the largest spiral galaxies known, with a physical size greater than 150 kpc. The SED of 17 regions (10 kpc of diameter) across the two arms show a remarkable spatial distribution, as if they were mirror images with respect to their stellar population. However, the last 40 kpc of the northeastern arm are much bluer than any other region of the southwestern one. There is a strong spatial correlation between the NUV luminosity and the distance to the nucleus. The UV data supports the scenario of an interaction at 130 Myr which triggered star formation all over the disk of NGC 6872. The tip of the northeastern arm resembles a tidal dwarf galaxy in the process of formation.

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Two Double Galaxy Systems

Publications of the Astronomical Society of Australia ◽

10.1017/s1323358000011942 ◽

1969 ◽

Vol 1 (6) ◽

pp. 288-289 ◽

Cited By ~ 2

Author(s):

B. M. Lewis

Keyword(s):

High Resolution ◽

Mass Distribution ◽

Differential Rotation ◽

Large Scale ◽

Spiral Galaxies ◽

Circular Symmetry ◽

Present Epoch ◽

Double Galaxy ◽

The Galaxy ◽

M 31

It is generally assumed from an inspection of prints of non-magellanic spiral galaxies that all constituents, including the HI, are distributed with a large-scale circular symmetry in the plane of the galaxy. This assumption is supported by the expectation that any primordial asymmetry in the mass distribution would have disintegrated by the present epoch under the shearing effects of differential rotation into an approximately circularly symmetric ring. It is therefore surprising to find that the recent high-resolution studies of M 31, M 101, NGC 300 and our own galaxy all show that the HI centroid is significantly displaced from the nucleus. This is a sign that the HI distribution is markedly asymmetric.

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Dark Matter

Symposium - International Astronomical Union ◽

10.1017/s0074180900159807 ◽

1987 ◽

Vol 124 ◽

pp. 699-712 ◽

Cited By ~ 3

Author(s):

R. Sancisi ◽

T.S. van Albada

Keyword(s):

Dark Matter ◽

Spatial Distribution ◽

Spiral Galaxies ◽

Stellar System ◽

Large Mass ◽

Observational Evidence ◽

Density Parameter ◽

Clusters Of Galaxies ◽

The Galaxy

The observational evidence for unseen matter is briefly reviewed for objects ranging from small to very large scales. The existence of large mass discrepancies is clearly recognized in individual spiral galaxies and in rich clusters of galaxies. For other systems - dwarfs, ellipticals, binaries and groups - the results are more uncertain and still rather controversial. The data on spirals indicate values of the cosmological density parameter Ω around 0.02, those on clusters Ω ≃ 0.2. The spatial distribution of this dark matter is still largely unknown: while on the galaxy scale it must be located mainly in the outer parts of the stellar system, in clusters it is unclear whether it follows the distribution of the visible galaxies or not.

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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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