scholarly journals TiO bands in composite systems

1993 ◽  
Vol 153 ◽  
pp. 313-314
Author(s):  
A. Milone ◽  
B. Barbuy
Keyword(s):  
Globular Cluster ◽  
Elliptical Galaxies ◽  
Galactic Bulge ◽  
Composite Systems ◽  
Composite Spectra

TiO bands at λ 620 nm are synthesized. The behaviour of these bands as a function of stellar parameters is studied. Application to composite spectra of one galactic bulge globular cluster and to bulges of elliptical galaxies is also carried out. TiO bands may be useful metallicity indicators.

scholarly journals Proto–Globular Cluster Candidates in NGC 1275

1999 ◽  
Vol 186 ◽  
pp. 273-274
Author(s):  
Jean P. Brodie
Keyword(s):  
Globular Cluster ◽  
Spiral Galaxies ◽  
Cluster Formation ◽  
Elliptical Galaxies ◽  
Cooling Flows ◽  
Ngc 1275 ◽  
Perseus Cluster ◽  
Important Test

The discovery, with HST imaging, of proto–globular cluster candidates in NGC 1275 (Holtzman et al. 1992) was regarded by many as a major success of the merger model for globular cluster formation (e.g. Ashman & Zepf 1992) and has been cited in support of the idea that elliptical galaxies form from the merger of two or more spiral galaxies. A prediction of the Ashman & Zepf model was that newly-formed clusters should be observable in currently or recently merging systems. The NGC 1275 clusters constitute an important test of globular cluster formation models. NGC 1275 is the peculiar cD galaxy at the center of the Perseus cluster. It shows evidence for a merger history and may indeed be undergoing a merger at present. It also has one of the largest known cooling flows.

scholarly journals EXPLORING THE ROLE OF GLOBULAR CLUSTER SPECIFIC FREQUENCY ON THE NOVA RATES IN THREE VIRGO ELLIPTICAL GALAXIES

2015 ◽  
Vol 811 (1) ◽  
pp. 34 ◽  
Author(s):  
C. Curtin ◽  
A. W. Shafter ◽  
C. J. Pritchet ◽  
J. D. Neill ◽  
A. Kundu ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Elliptical Galaxies ◽  
Specific Frequency

scholarly journals The Formation and Evolution of Star Clusters and Galaxies

2005 ◽  
Vol 13 ◽  
pp. 347-349
Author(s):  
Stephen E. Zepf
Keyword(s):  
Galaxy Formation ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Near Infrared ◽  
Cluster Formation ◽  
Star Clusters ◽  
Elliptical Galaxies ◽  
Cluster Systems ◽  
Important Observation ◽  
Formation And Evolution

AbstractThis paper addresses the questions of what we have learned about how and when dense star clusters form, and what studies of star clusters have revealed about galaxy formation and evolution. One important observation is that globular clusters are observed to form in galaxy mergers and starbursts in the local universe, which both provides constraints on models of globular cluster formation, and suggests that similar physical conditions existed when most early-type galaxies and their globular clusters formed in the past. A second important observation is that globular cluster systems typically have bimodal color distributions. This was predicted by merger models, and indicates an episodic formation history for elliptical galaxies. A third and very recent result is the discovery of large populations of intermediate age globular clusters in several elliptical galaxies through the use of optical to near-infrared colors. These provide an important link between young cluster systems observed in starbursts and mergers and old cluster systems. This continuum of ages of the metal-rich globular cluster systems also indicates that there is no special age or epoch for the formation of the metal-rich globular clusters, which comprise about half of the cluster population. The paper concludes with a brief discussion of recent results on the globular cluster – low-mass X-ray binary connection.

scholarly journals Mercer 5: a probable new globular cluster in the Galactic bulge

2011 ◽  
pp. no-no ◽  
Author(s):  
A. J. Longmore ◽  
R. Kurtev ◽  
P. W. Lucas ◽  
D. Froebrich ◽  
R. de Grijs ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Galactic Bulge

scholarly journals The history of the Galactic bulge

2016 ◽  
Vol 12 (S323) ◽  
pp. 184-187 ◽  
Author(s):  
A. A. Zijlstra ◽  
K. Gesicki ◽  
M. M. Miller Bertolami
Keyword(s):  
Star Formation ◽  
Planetary Nebulae ◽  
Elliptical Galaxies ◽  
Recent Analysis ◽  
Galactic Bulge ◽  
Luminosity Functions ◽  
New Models ◽  
Show Evidence ◽  
History Of ◽  
Star Formation Histories

AbstractPlanetary nebulae form in stellar populations with ages from 1 to 10 Gyr, and can be used to trace their star formation histories. Here we apply this to the Galactic bulge, where there are indications both for an old origin and for younger stars. We use new stellar models, which have significant different evolutionary speeds during the post-AGB phase. We apply these new models to a sample of 32 planetary nebulae with HST imaging and VLT spectroscopy. The results show evidence for an old starburst, followed by continuous star formation until at least 2Gyr ago. This agrees very well with recent analysis of colour-magnitude diagrams of the bulge. We show that the new models can also explain the [OIII] luminosity functions, and predict the uniform luminosity cut-off both in spiral galaxies and old elliptical galaxies.

scholarly journals Evolution of Globular Cluster Systems in Elliptical Galaxies

2002 ◽  
Vol 207 ◽  
pp. 664-672
Author(s):  
Enrico Vesperini
Keyword(s):  
Globular Cluster ◽  
Total Mass ◽  
Mass Function ◽  
Elliptical Galaxies ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Evolutionary Processes ◽  
Cluster Systems ◽  
Massive Galaxies

We study the evolution of the main properties of globular cluster systems in elliptical galaxies. In particular, we focus our attention on the evolution of the mass function of globular cluster systems (GCMF), on the fraction of surviving clusters and on the ratio of the final to initial total mass in clusters and we explore the dependence of these properties on the structure of the host galaxy and on the initial GCMF. We show that the observed universality of the GCMF parameters in galaxies with different structures can be reconciled with the effects of evolutionary processes and with the significant differences in the efficiency of evolutionary processes in different host galaxies; the final mean masses of globular cluster systems in massive galaxies can be very similar to each other with a small galaxy-to-galaxy dispersion in spite of large differences in the fraction of surviving clusters.

scholarly journals Multimodal Color Distributions in the Globular Cluster Systems of Giant Elliptical Galaxies

1999 ◽  
Vol 186 ◽  
pp. 197-197
Author(s):  
D. Geisler ◽  
M.G. Lee
Keyword(s):  
Globular Cluster ◽  
Surface Density ◽  
Cluster Formation ◽  
Elliptical Galaxies ◽  
Small Cluster ◽  
Cluster Systems ◽  
Density Distributions ◽  
Collapse Model

We report on new observations of the globular cluster systems (GCSs) of two galaxies: M86 (NGC 4406) in Virgo and NGC 4696, the central giant elliptical (gE) in the Centaurus cluster. Previous observations in M86 showed no evidence for bimodality, but using only (V - I) for small cluster samples. The NGC 4696 GCS is unstudied. We used the integrated Washington (C - T1) color. This metallicity index is more than twice as sensitive to [Fe/H] as (V - I). In M86 we have about 1100 good GC candidates, and about 650 in NGC 4696, with mean internal metallicity errors ~ 0.15 dex. Both of these GCSs are found to have bimodal metallicity distributions (MDs). Our data strengthen previous results that MDs for the GCSs of gEs are widespread. The evidence for 2 separate populations in these galaxies is corroborated by examining the surface density distributions: the metal-rich clusters are more centrally concentrated than their metal-poor counterparts. The overall radial metallicity gradient present in the M86 GCS is due to the varying radial mix of the 2 populations. The existence of 2 GC populations signifies that there were 2 distinct epochs or events of cluster formation in a gE. The simple collapse model of gE formation is ruled out.

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