Space Velocities of Globular Clusters. III. Cluster Orbits and Halo Substructure

Dinescu, D. I.; Girard, Terrence M.; Altena, W. F. van

doi:10.1086/300807

Cited by 449 publications

(703 citation statements)

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“…Criteria using the space velocity V, as proposed by Dinescu, Girard, & van Altena (1997), Dinescu, van Altena, & Girard (1999a), Dinescu, Girard, & van Altena (1999b), Dinescu et al (2003), and Casetti- Dinescu et al (2007Dinescu et al ( , 2010Dinescu et al ( , 2013, are only feasible if proper motions are available, besides radial velocities. In particular, Dinescu et al (2003) verified the classification of clusters as members of different galaxy components in terms of kinematics.…”

Section: The Sample Of Bulge Globular Clustersmentioning

confidence: 99%

Globular Clusters in the Galactic Bulge

Bica

Ortolani

Barbuy

2016

Publ. Astron. Soc. Aust.

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A view of the Galactic bulge by means of their globular clusters is fundamental for a deep understanding of its formation and evolution. Connections between the globular cluster and field star properties in terms of kinematics, orbits, chemical abundances, and ages should shed light on different stellar population components. Based on spatial distribution and metallicity, we define a probable best list of bulge clusters, containing 43 entries. Future work on newly discovered objects, mostly from the VVV survey, is suggested. These candidates might alleviate the issue of missing clusters on the far side of the bulge. We discuss the reddening law affecting the cluster distances towards the centre of the Galaxy, and conclude that the most suitable total-to-selective absorption value appears to be R V =3.2, in agreement with recent analyses. An update of elemental abundances for bulge clusters is provided.

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Section: The Sample Of Bulge Globular Clustersmentioning

confidence: 99%

Globular Clusters in the Galactic Bulge

Bica

Ortolani

Barbuy

2016

Publ. Astron. Soc. Aust.

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“…These times are given in Gyr in Table 2 (assuming a value of 10 Gyr for a Hubble time) where the two values of the total destruction rate given by Gnedin & Ostriker (1997) for the two galactic models used in their calculations have been averaged in column (10). The observed clusters cover quite a large range of T d from a minimum of 4 Gyr for NGC 6397 to 213 Gyr for NGC 5272 (using Gnedin & Ostriker's values), or from 2 Gyr for NGC 6121 to 275 Gyr for NGC 5272 (following Dinescu et al 1999). These values should in principle be regarded as upper limits to the true T d , as both Gnedin & Ostriker and Dinescu et al treat the internal dynamical evolution of the clusters by using single-mass Michie-King models and, thus, tend to underestimate the effects of mass segregation.…”

Section: Physical Data and Tidal Disruptionmentioning

confidence: 99%

“…In particular, the LF of the four clusters in the sample that extend well beyond the peak luminosity down to close to the Hydrogen burning limit (NGC 6341, NGC 6397, NGC 6752, and NGC 6809) can only be reproduced by such distributions and not by a single power-law in the 0.1 − 0.6 M ⊙ range. After correction for the effects of mass segregation, the variation of the ratio of the number of higher to lower mass stars with cluster mass or any simple orbital parameter or the expected time to disruption recently computed for these clusters by Gnedin & Ostriker (1997) and Dinescu et al (1999) shows no statistically significant trend over a range of this last parameter of more than a factor of ∼ 100. We conclude that the global MF of these clusters have not been measurably modified by evaporation and tidal interactions with the Galaxy and, thus, should reflect the initial distribution of stellar masses.…”

mentioning

confidence: 92%

On the Globular Cluster IMF Below 1 M⊙

Paresce

Marchi

2000

The Evolution of the Milky Way

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Accurate luminosity functions (LF) for a dozen globular clusters have now been measured at or just beyond their half-light radius using HST. They span almost the entire cluster main sequence (MS) below 0.75 M ⊙ . All these clusters exhibit LF that rise continuously from an absolute I magnitude M I ≃ 6 to a peak at M I ≃ 8.5−9 and then drop with increasing M I . Transformation of the LF into mass functions (MF) by means of the mass luminosity (ML) relations of Baraffe et al. (1997) and Cassisi et al. (1999) that are consistent with all presently available data on the physical properties of low mass, low metallicity stars shows that all the LF observed so far can be obtained from MF having the shape of a log-normal distribution with characteristic mass m c = 0.33 ± 0.03 M ⊙ and standard deviation σ = 1.81 ± 0.19. In particular, the LF of the four clusters in the sample that extend well beyond the peak luminosity down to close to the Hydrogen burning limit (NGC 6341, NGC 6397, NGC 6752, and NGC 6809) can only be reproduced by such distributions and not by a single power-law in the 0.1 − 0.6 M ⊙ range. After correction for the effects of mass segregation, the variation of the ratio of the number of higher to lower mass stars with cluster mass or any simple orbital parameter or the expected time to disruption recently computed for these clusters by Gnedin & Ostriker (1997) and Dinescu et al. (1999) shows no statistically significant trend over a range of this last parameter of more than a factor of ∼ 100. We conclude that the global MF of these clusters have not been measurably modified by evaporation and tidal interactions with the Galaxy and, thus, should reflect the initial distribution of stellar masses. Since 1 Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS5-26555 -2 -the log-normal function that we find is also very similar to the one obtained independently for much younger clusters and to the form expected theoretically, the implication seems to be unavoidable that it represents the true stellar IMF for this type of stars in this mass range.

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“…Three other subjects deserve some comment. First, Dinescu, Girard &;van Altena (1999) have complied a catalogue of absolute proper motions for 38 globular clusters, including 15 southern clusters measured as part of their own program (see references in Dinescu et al 1999). These motions were used as a basis for orbit integrations using models of the Galaxy's potential.…”

Section: Abundance Anomaliesmentioning

confidence: 99%

Commission 37: Star Clusters and Associations: (Amas Stellaires et Associations)

Costa¹,

Meylan²,

Aarseth³

et al. 2000

Trans. Int. Astron. Union

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With the exception of the activities associated with the XXIII IAU General Assembly in Kyoto, Japan, in August 1997, the report period (July 1, 1996 through June 30, 1999) has been a relatively quiet one for Commission 37. Commission activities have been restricted primarily to the consideration of proposals for IAU Symposia and Colloquia together with some activity related to cluster nomenclature issues. At the General Assembly the commission was involved in either supporting or co-supporting four Joint Discussion sessions and one of the accompanying Symposia. Eighteen new members were added to the commission, increasing membership by just under 10%.

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Space Velocities of Globular Clusters. III. Cluster Orbits and Halo Substructure

Cited by 449 publications

References 58 publications

Globular Clusters in the Galactic Bulge

Globular Clusters in the Galactic Bulge

On the Globular Cluster IMF Below 1 M⊙

Commission 37: Star Clusters and Associations: (Amas Stellaires et Associations)

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