scholarly journals The Status of Absolute Proper Motions and the Kinematics of Globular Clusters

1995 ◽  
Vol 164 ◽  
pp. 406-406 ◽  
Author(s):  
M. Geffert ◽  
B. Dauphole ◽  
J. Colin ◽  
M. Odenkirchen ◽  
H.-J. Tucholke ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Radial Velocities ◽  
Proper Motions ◽  
Preliminary Results ◽  
Space Motion ◽  
The Status ◽  
Galactic Potentials ◽  
Total Energies

We have studied a sample of 26 globular clusters for which so far absolute proper motions exist in the literature. The proper motions were combined with distances and radial velocities for a determination of the space motion of the clusters. Using different galactic potentials (see Dauphole & Colin 1994 and references therein) we calculated the orbits of the globular clusters and their time averaged eccentricities, total energies, and apo- and perigalactic distances. The relation of the orbital quantities to the metallicities of the globular clusters has been studied. Preliminary results of this study were presented in Geffert et al. (1993).

scholarly journals Absolute Proper and Space Motion of the Globular Cluster M2

1994 ◽  
Vol 161 ◽  
pp. 464-466
Author(s):  
M. Geffert ◽  
C. Forner ◽  
M. Hiesgen ◽  
A.R. Klemola
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Milky Way ◽  
Reference Frames ◽  
Proper Motions ◽  
The Past ◽  
Motion Study ◽  
Space Motion ◽  
First Results

Space motions of globular clusters are important for the understanding of the kinematics and chemical evolution of the Milky Way. The greatest problem for the determination of the space motions of the globular clusters arises from the difficulties of getting absolute proper motions. In the past these were determined using classical stellar reference frames, modelling of the non-cluster stars in the field and extragalactic objects in the region of the cluster (see e.g. Cudworth & Hanson 1993; Geffert et al. 1993 for references). However, as shown for M 15 and M 3 (Geffert et al. 1993; Tucholke et al. 1993), the results based on different methods for deriving the absolute proper motions differ by up to yrs. In order to get a more complete view of the differences between the various methods it is therefore very interesting to get absolute proper motions based on all three methods for further objects. We present here the first results of a new proper motion study of the globular cluster M 2.

scholarly journals Testing for Dark Matter in the Outskirts of Globular Clusters

2021 ◽  
Vol 922 (2) ◽  
pp. 104
Author(s):  
Raymond G. Carlberg ◽  
Carl J. Grillmair
Keyword(s):  
Dark Matter ◽  
Globular Clusters ◽  
High Probability ◽  
Velocity Dispersion ◽  
High Redshift ◽  
Dark Matter Halo ◽  
The Sun ◽  
Proper Motions ◽  
Preliminary Results ◽  
Galactic Background

Abstract The proper motions of stars in the outskirts of globular clusters are used to estimate cluster velocity dispersion profiles as far as possible within their tidal radii. We use individual color–magnitude diagrams to select high-probability cluster stars for 25 metal-poor globular clusters within 20 kpc of the Sun, 19 of which have substantial numbers of stars at large radii. Of the 19, 11 clusters have a falling velocity dispersion in the 3–6 half-mass radii range, 6 are flat, and 2 plausibly have a rising velocity dispersion. The profiles are all in the range expected from simulated clusters that started at high redshift in a zoom-in cosmological simulation. The 11 clusters with falling velocity dispersion profiles are consistent with no dark matter above the Galactic background. The six clusters with approximately flat velocity dispersion profiles could have local dark matter, but are ambiguous. The two clusters with rising velocity dispersion profiles are consistent with a remnant local dark matter halo, but need membership confirmation and detailed orbital modeling to further test these preliminary results.

scholarly journals Orbits of Galactic Globular Clusters from Schmidt Plate Astrometry

1994 ◽  
Vol 161 ◽  
pp. 453-459 ◽  
Author(s):  
M. Odenkirchen ◽  
R.-D. Scholz ◽  
M.J. Irwin
Keyword(s):  
Globular Clusters ◽  
Proper Motions ◽  
Mass Model ◽  
Orbital Parameters ◽  
The Galaxy ◽  
Galactic Globular Clusters

We present results from orbit integrations for the globular clusters M 3 and M 92. Absolute proper motions recently measured from Tautenburg Schmidt plates and a three-component mass model for the Galaxy have been used to derive the galactic orbits of these clusters. Orbital parameters and the influence of observational uncertainties on the determination of the orbits are discussed.

scholarly journals Globular clusters in the Fornax cluster: A report from the FDS survey

2019 ◽  
Vol 14 (S351) ◽  
pp. 68-71
Author(s):  
Michele Cantiello ◽  
A. Venhola ◽  
M. Paolillo ◽  
R. D’Abrusco ◽  
A. Grado ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Accurate Determination ◽  
Galaxy Interactions ◽  
The Galaxy ◽  
The Status ◽  
Deep Survey ◽  
Dimensional Distribution ◽  
Fornax Cluster ◽  
Galaxy Luminosity Function

AbstractThe Fornax Deep Survey (FDS) is a multi-band imaging survey of the Fornax cluster of galaxies, executed with the ESO VLT Survey Telescope (VST). The survey is designed to reach unprecedented surface brightness and point-source magnitude depth over one virial radius of the cluster. The scientific objectives of the survey are numerous: the study of the galaxy luminosity function, derivation of galaxy scaling relations, determination of the properties of compact stellar systems, an accurate determination of distances and 3-D geometry of the Fornax cluster, analysis of diffuse stellar light and galaxy interactions, etc.In this contribute we give an overview on the interest of the survey on globular clusters (GC) populations, and present a report the status of the study of GCs also providing some preliminary results of our analysis, with particular regard to the two-dimensional distribution of GC candidates over ∼20 sq. degree area of Fornax centered on NGC 1399.

scholarly journals A Determination of Secular Parallaxes of Reference Stars from Relative Proper Motions of Open Clusters

1970 ◽  
Vol 7 ◽  
pp. 74-76
Author(s):  
A. N. Deutsch
Keyword(s):  
Systematic Errors ◽  
Open Clusters ◽  
Radial Velocities ◽  
Proper Motions ◽  
The Mean

The determination of secular parallaxes of stars is usually based on meridian observations of proper motions of bright stars, this introducing known systematic errors. The mean parallaxes of stars can be obtained by means of radial velocities which are known for the bright stars. The more perspective method, the reference of stars to galaxies, is not applicable at low galactic latitudes.

The Status of Absolute Proper Motions and the Kinematics of Globular Clusters

1995 ◽  
pp. 406-406
Author(s):  
M. Geffert ◽  
B. Dauphole ◽  
J. Colin ◽  
M. Odenkirchen ◽  
H.-J Tucholke ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Proper Motions ◽  
The Status

scholarly journals Astrometric Distances of Globular Clusters

1988 ◽  
Vol 126 ◽  
pp. 523-524
Author(s):  
Kyle Cudworth ◽  
Ruth C. Peterson
Keyword(s):  
Radial Velocity ◽  
High Precision ◽  
Proper Motion ◽  
Globular Clusters ◽  
Small Distance ◽  
Radial Velocities ◽  
Proper Motions ◽  
Velocity Dispersions

With high-precision radial velocities and proper motions, one can equate the proper motion and radial velocity dispersions to obtain astrometric distances independent of any standard candles. We discuss the method and the small distance it yields to M 22.

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