Globular Clusters as Tracers of the Galaxy Mass Distribution

1988 ◽  
pp. 423-427
Author(s):  
K. A. Innanen
Keyword(s):  
Mass Distribution ◽  
Globular Clusters ◽  
The Galaxy

scholarly journals An Upper Limit to the Mass Loss from the Centre of the Galaxy

1974 ◽  
Vol 64 ◽  
pp. 36-36
Author(s):  
Arcadio Poveda ◽  
Christine Allen
Keyword(s):  
Mass Loss ◽  
Gravitational Waves ◽  
Mass Distribution ◽  
Globular Clusters ◽  
Loss Rate ◽  
Galactic Centre ◽  
Isotropic Source ◽  
The Past ◽  
Upper Limit ◽  
The Galaxy

A mass loss of 200 M⊙ per year, as conservatively suggested if Weber is detecting gravitational waves from an isotropic source at the galactic centre, is shown to be incompatible with the existence of (a) globular clusters, (b) old wide binaries, if this loss rate has been constant over the past 1010 yr.From the orbit of ω Centauri in the galactic field and its observed mass distribution and tidal radius an upper limit to the mass loss from the galactic centre is found to be 1 M⊙ yr-1 over the past 1010 yr.

scholarly journals Structural and Kinematic Properties of Populations of the Andromeda Galaxy

1972 ◽  
Vol 44 ◽  
pp. 37-45 ◽  
Author(s):  
J. Einasto
Keyword(s):  
Mass Distribution ◽  
Globular Clusters ◽  
Velocity Dispersion ◽  
Strong Dependence ◽  
Stellar Content ◽  
Distribution Models ◽  
Model Calculations ◽  
The Galaxy ◽  
Spectrophotometric Data ◽  
Virial Mass

New observational data (Spinrad, 1970; Van den Bergh, 1970; Rubin and Ford, 1970) are used to determine structural and kinematic parameters of the nucleus, the subsystem of globular clusters, and interstellar hydrogen in M31.The mass derived for the nucleus from the new spectrophotometric data is in good agreement with the virial mass 6 × 108M⊙. Model calculations show that there is no appreciable exchange of stars between the nucleus and the bulge. The rotation energy of the nucleus is only 7.5% of the total kinetic energy; the central density is 2 × 106M⊙ pc−3.The mean radius of the subsystem of globular clusters is 4.5 kpc. This indicates that the subsystem of old stars is not identical with the spheroidal component of the galaxy, whose mean radius is only 1 kpc. Radial velocity dispersion of globular clusters is only half of that of the nucleus. This shows a strong dependence of the velocity dispersion on distance to the center of the galaxy and a bias in mass determination of a galaxy from velocity dispersion near the nucleus.On the basis of data on rotation two mass distribution models have been found, differing from each other in respect of the mass concentration to the center. Spectrophotometric data on the stellar content of the bulge are urgently needed to solve the mass distribution problem.

Extra-tidal features using Gaia DR2

2019 ◽  
Vol 14 (S351) ◽  
pp. 420-421
Author(s):  
Julio A. Carballo-Bello
Keyword(s):  
Mass Distribution ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Milky Way ◽  
Space Mission ◽  
Cluster Center ◽  
Proper Motions ◽  
The Galaxy ◽  
Tidal Tails ◽  
Gaia Dr2

AbstractIn recent years, we have gathered enough evidence showing that most of the Galactic globular clusters extend well beyond their King tidal radii and fill their Jacobi radii in the form of “extended stellar haloes”. In some cases, because of the interaction with the Milky Way, stars are able to exceed the Jacobi radius, generating tidal tails which may be used to trace the mass distribution in the Galaxy. In this work, we use the precious information provided by the space mission Gaia (photometry, parallaxes and proper motions) to analyze NGC 362 in the search for member stars in its surroundings. Our preliminar results suggest that it is possible to identify member stars and tidal features up to distances of a few degrees from the globular cluster center.

scholarly journals Globular Clusters as Tracers of the Galaxy Mass Distribution

1988 ◽  
Vol 126 ◽  
pp. 423-429
Author(s):  
K. A. Innanen
Keyword(s):  
Mass Distribution ◽  
Globular Clusters ◽  
New Method ◽  
Local Standard ◽  
The Galaxy ◽  
Local Standard Of Rest

This review will consist of two parts: (a) a brief description of a new method to determine Vo, the circular speed of the local standard of rest, and which, of course, plays a fundamental role in the mass distribution of the Galaxy, and (b) a review of the globular clusters as tracers of the mass distribution in the Galaxy.

scholarly journals The accreted nuclear clusters of the Milky Way

2020 ◽  
Vol 500 (2) ◽  
pp. 2514-2524
Author(s):  
Joel Pfeffer ◽  
Carmela Lardo ◽  
Nate Bastian ◽  
Sara Saracino ◽  
Sebastian Kamann
Keyword(s):  
Globular Clusters ◽  
Milky Way ◽  
Dwarf Galaxy ◽  
Star Clusters ◽  
Host Galaxy ◽  
The Galaxy ◽  
Nuclear Clusters ◽  
The Common ◽  
Massive Clusters ◽  
Peculiar Case

ABSTRACT A number of the massive clusters in the halo, bulge, and disc of the Galaxy are not genuine globular clusters (GCs) but instead are different beasts altogether. They are the remnant nuclear star clusters (NSCs) of ancient galaxies since accreted by the Milky Way. While some clusters are readily identifiable as NSCs and can be readily traced back to their host galaxy (e.g. M54 and the Sagittarius Dwarf galaxy), others have proven more elusive. Here, we combine a number of independent constraints, focusing on their internal abundances and overall kinematics, to find NSCs accreted by the Galaxy and trace them to their accretion event. We find that the true NSCs accreted by the Galaxy are: M54 from the Sagittarius Dwarf, ω Centari from Gaia-Enceladus/Sausage, NGC 6273 from Kraken, and (potentially) NGC 6934 from the Helmi Streams. These NSCs are prime candidates for searches of intermediate-mass black holes (BHs) within star clusters, given the common occurrence of galaxies hosting both NSCs and central massive BHs. No NSC appears to be associated with Sequoia or other minor accretion events. Other claimed NSCs are shown not to be such. We also discuss the peculiar case of Terzan 5, which may represent a unique case of a cluster–cluster merger.

scholarly journals Anisotropy in ω Centauri and 47 Tucanae

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).

scholarly journals What to expect when using globular clusters as tracers of the total mass distribution in Milky Way-mass galaxies

2021 ◽  
Vol 502 (2) ◽  
pp. 2828-2844
Author(s):  
Meghan E Hughes ◽  
Prashin Jethwa ◽  
Michael Hilker ◽  
Glenn van de Ven ◽  
Marie Martig ◽  
...  
Keyword(s):  
Dark Matter ◽  
Radial Distribution ◽  
Globular Clusters ◽  
Dominant Factor ◽  
Quality Uncertainty ◽  
Dynamical Models ◽  
Accuracy And Precision ◽  
The Galaxy ◽  
Dark Matter Distribution ◽  
Ideal Tracer

ABSTRACT Dynamical models allow us to connect the motion of a set of tracers to the underlying gravitational potential, and thus to the total (luminous and dark) matter distribution. They are particularly useful for understanding the mass and spatial distribution of dark matter (DM) in a galaxy. Globular clusters (GCs) are an ideal tracer population in dynamical models, since they are bright and can be found far out into the halo of galaxies. We aim to test how well Jeans-Anisotropic-MGE (JAM) models using GCs (positions and line-of-sight velocities) as tracers can constrain the mass and radial distribution of DM haloes. For this, we use the E-MOSAICS suite of 25 zoom-in simulations of L* galaxies. We find that the DM halo properties are reasonably well recovered by the JAM models. There is, however, a strong correlation between how well we recover the mass and the radial distribution of the DM and the number of GCs in the galaxy: the constraints get exponentially worse with fewer GCs, and at least 150 GCs are needed in order to guarantee that the JAM model will perform well. We find that while the data quality (uncertainty on the radial velocities) can be important, the number of GCs is the dominant factor in terms of the accuracy and precision of the measurements. This work shows promising results for these models to be used in extragalactic systems with a sample of more than 150 GCs.

scholarly journals Where Does the Galaxy End?

1996 ◽  
Vol 169 ◽  
pp. 669-680
Author(s):  
F.D.A. Hartwick
Keyword(s):  
Spatial Distribution ◽  
Globular Clusters ◽  
Semimajor Axis ◽  
Three Dimensional ◽  
Minor Axis ◽  
Spatial Extension ◽  
The Galaxy ◽  
Nested Hierarchy ◽  
Satellite Galaxies ◽  
Dimensional Surface

The spatial distribution of the outlying satellites of the Galaxy has been determined by fitting a three dimensional surface to the positions of 10 companion galaxies and 13 distant globular clusters. Both groups show a highly flattened distribution whose minor axes are aligned to within ∼ 5°. The combined group of 23 objects shows a triaxial distribution with semimajor axis extending ∼ 400 kpc. The minor axis is inclined at ∼ 76° to the Galactic poles. There is a suggestion of a nested hierarchy consisting of satellite galaxies, globular clusters, and distant halo field stars, in order of decreasing spatial extension.

scholarly journals Hidden infrared star clusters in our Galaxy: follow-up observations

2009 ◽  
Vol 5 (S266) ◽  
pp. 366-366
Author(s):  
Jura Borissova ◽  
Radostin Kurtev ◽  
Margaret M. Hanson ◽  
Leonid Georgiev ◽  
Valentin Ivanov ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Star Cluster ◽  
Open Clusters ◽  
Star Formation History ◽  
Stellar Disk ◽  
Physical Parameters ◽  
Formation History ◽  
The Galaxy ◽  
History Of ◽  
Infrared Star

AbstractWe are reporting some recent results from our long-term program aimed at characterizing the obscured present-day star cluster population in the Galaxy. Our goal is to expand the current census of the Milky Way's inner stellar disk to guide models seeking to understand the structure and recent star-formation history of our Galaxy. The immediate goal is to derive accurate cluster physical parameters using precise infrared photometry and spectroscopy. So far, we observed approximately 60 star cluster candidates selected from different infrared catalogs. Their nature, reddening, distance, age and mass are analyzed. Two of them, Mercer 3 and Mercer 5, are new obscured Milky Way globular clusters. Among the newly identified open clusters, the objects [DBS2003] 179, Mercer 23, Mercer 30, Mercer 70, and [DBS2003] 106 are particularly interesting because they contain massive young OB and Wolf–Rayet stars with strong emission lines.

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