Infrared array photometry of metal-rich globular clusters. 1: Techniques and first results

1995 ◽  
Vol 109 ◽  
pp. 1131 ◽  
Author(s):  
Leslie E. Kuchinski ◽  
Jay A. Frogel ◽  
D. M. Terndrup ◽  
S. E. Persson
Keyword(s):  
Globular Clusters ◽  
First Results ◽  
Infrared Array

Space velocities of southern globular clusters. I. Astrometric techniques and first results.

1997 ◽  
Vol 114 ◽  
pp. 1014 ◽  
Author(s):  
Dana I. Dinescu ◽  
Terrence M. Girard ◽  
William F. van Altena ◽  
Rene A. Mendez ◽  
Carlos E. Lopez
Keyword(s):  
Globular Clusters ◽  
First Results

scholarly journals The Dark Side of Globular Clusters

1996 ◽  
Vol 174 ◽  
pp. 377-378
Author(s):  
P.-Y. Longaretti ◽  
R. Taillet ◽  
P. Salati
Keyword(s):  
Globular Clusters ◽  
Mass Function ◽  
Dynamical Analysis ◽  
Dark Side ◽  
Low Mass Stars ◽  
First Results ◽  
Low Mass ◽  
Non Parametric

Searches of low-mass stars have become possible in globular clusters, and the first results suggest that the mass function turns up below ∼ 0.4 M⊙ (Fahlman et al. 1989; Richer et al., 1990; Richer et al. 1991; G. Piotto, these proceedings). This conclusion is independently supported by the non-parametric dynamical analysis of four clusters by Gebhardt and Fisher 1995.

scholarly journals 1.12. Structure of the inner galactic disk and the bulge - first results

1998 ◽  
Vol 184 ◽  
pp. 39-40
Author(s):  
S. Feltzing
Keyword(s):  
Observational Data ◽  
Globular Clusters ◽  
Spiral Galaxies ◽  
Galactic Disk ◽  
Galactic Bulge ◽  
Very Old ◽  
Difficult Question ◽  
First Results ◽  
Observational Status

Is there an age and/or a metallicity gradient in the Bulge? This is a notoriously difficult question because of the well known age-metallicity-distance degeneracy in colour magnitude diagrams (CMD) as well as the severe crowding and large reddening towards the Galactic Bulge. The current observational data on the bulge in our galaxy and bulges in other spiral galaxies point in disparate directions, that is evidence for both early (e.g. existence of very old halo and bulge globular clusters) and late formation (e.g. Sgr dSph and bar instabilities) can be found as well as the existence and non-existence of metallicity gradients (for a review of the observational status see Wyse, Gilmore & Franx 1997). We here present the CMDs for two fields, Baade's window and SGR-I, Fig.1c and d. Both these regions have low extinction. To determine the age and metallicity for these stars we compare the CMDs with CMDs of globular clusters, also observed with WFPC2, of known metallicity and age, Fig.1a and b. This method enables us to work entirely in the in-flight magnitude system of WFPC2 and there is no need for transformations to standard colours and magnitudes, something which is not straight forward for WFPC2 passbands.

scholarly journals Extragalactic Globular Cluster Systems in the Near-IR

2002 ◽  
Vol 207 ◽  
pp. 294-300 ◽  
Author(s):  
Thomas H. Puzia ◽  
Markus Kissler-Patig ◽  
Jean Brodie ◽  
Paul Goudfrooij ◽  
Michael Hilker ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Local Group ◽  
Optical Photometry ◽  
Cluster Systems ◽  
Near Ir ◽  
Galaxy Formation And Evolution ◽  
First Results ◽  
Formation And Evolution

Extragalactic Globular Clusters are useful tracers of galaxy formation and evolution. Photometric studies of globular cluster systems beyond the Local Group are still the most popular method to investigate their physical properties, such as their ages and metallicities. However, the limitations of optical photometry are well known. The better wavelength sampling of the underlying cluster's SED using K-band photometry combined with optical passbands allows us to create colors which reduce the age-metallicity degeneracy to the largest extent. Here we report on the very first results of our near-IR photometric survey of globular cluster systems in early-type galaxies outside the Local Group.

scholarly journals The age-abundance relations and age distributions for the star clusters of the Magellanic Clouds

1991 ◽  
Vol 148 ◽  
pp. 183-189 ◽  
Author(s):  
G. S. Da Costa
Keyword(s):  
Globular Clusters ◽  
Main Sequence ◽  
Galactic Halo ◽  
Large Population ◽  
Age Distribution ◽  
Magellanic Clouds ◽  
Number Of Clusters ◽  
First Results ◽  
Single Cluster ◽  
Cluster Age

A sample of Large Magellanic Clouds (LMC) and Small Magellanic Clouds (SMC) clusters for which ages have been directly determined from main sequence turnoff photometry has been compiled. According to this sample, the LMC and SMC cluster age distributions are very different. The LMC contains a large population of 1 to 3 Gyr old clusters as well as a small number of clusters that appear to be as old as the Galactic halo globular clusters. Surprisingly however, only a single cluster is known with an age in the interval between 3 Gyr and the age, taken as 15 Gyr, of the oldest clusters. The SMC age distribution, on the other hand, is much broader. It extends back to approximately 12 Gyr but there appear to be no SMC clusters as old as the oldest in the LMC. The sample of clusters is also used to discuss the age-abundance relations for both galaxies. Little can be learned for the LMC but it appears that the chemical evolution of the SMC differed in form from that experienced in the solar neighbourhood. The first results of an imaging survey designed to find LMC clusters with ages exceeding 3 Gyr are also described.

scholarly journals Globular Cluster Systems in the Hydra I Galaxy Cluster

2002 ◽  
Vol 207 ◽  
pp. 281-286
Author(s):  
Michael Hilker
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Dwarf Galaxies ◽  
Star Clusters ◽  
Galaxy Cluster ◽  
Cluster Center ◽  
Early Type ◽  
Cluster Systems ◽  
First Results ◽  
Globular Cluster System

In this contribution, first results of deep VLT (V,I) photometry in the central region of the Hydra I galaxy cluster are presented. Many star clusters have been identified not only around several early-type galaxies, but also in the intra-cluster field, as far as 250 kpc from the cluster center. Outside the bulges of the central galaxies NGC 3311 and NGC 3309, the intra-cluster globular cluster system is dominated by blue clusters whose spatial distribution is similar to that of the (newly discovered) dwarf galaxies in Hydra I. The color distributions of globular clusters around NGC 3311 and NGC 3309 are multimodal, with a sharp blue peak and a slightly broader distribution of the red cluster population.

Deep Infrared Array Photometry of Globular Clusters. V. M28 (NGC 6626)

1996 ◽  
Vol 468 ◽  
pp. 641 ◽  
Author(s):  
T. J. Davidge ◽  
Patrick Cote ◽  
W. E. Harris
Keyword(s):  
Globular Clusters ◽  
Infrared Array

Infrared array photometry of metal rich globular clusters. 2: Liller 1--the most metal rich cluster?

1995 ◽  
Vol 109 ◽  
pp. 1154 ◽  
Author(s):  
Jay A. Frogel ◽  
Leslie E. Kuchinski ◽  
Glenn P. Tiede
Keyword(s):  
Globular Clusters ◽  
Rich Cluster ◽  
Infrared Array
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