scholarly journals Globular Clusters in Elliptical Galaxies: Constraints on Mergers

1999 ◽  
Vol 186 ◽  
pp. 181-184
Author(s):  
Duncan A. Forbes
Keyword(s):  
Galaxy Formation ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Elliptical Galaxies ◽  
Cluster System ◽  
Cluster Systems ◽  
Chemical Enrichment ◽  
Formation And Evolution ◽  
Globular Cluster System ◽  
Parent Galaxy

There exists a relationship between globular cluster mean metallicity and parent galaxy luminosity (e.g. Brodie & Huchra 1991; Forbes et al. 1996), which appears to be similar to that between stellar metallicity and galaxy luminosity. The globular cluster relation has a similar slope but is offset by about 0.5 dex to lower metallicity. The similarity of these relations suggests that both the globular cluster system and their parent galaxy have shared a common chemical enrichment history. If we can understand the formation and evolution of the globulars, we will also learn something about galaxy formation. With this aim in mind we have created the SAGES (Study of the Astrophysics of Globular clusters in Extragalactic Systems) project. Project members include Brodie, Elson, Forbes, Freeman, Grillmair, Huchra, Kissler–Patig and Schroder. We are using HST Imaging and Keck spectroscopy to study extragalactic globular cluster systems. Further details are given at http://www.ucolick.org/~mkissler/Sages/sages.html.

scholarly journals Observational Constraints on the Formation and Evolution of Globular Cluster Systems

2007 ◽  
Vol 3 (S246) ◽  
pp. 394-402
Author(s):  
Stephen E. Zepf
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Dynamical Evolution ◽  
Mass Function ◽  
Cluster System ◽  
Host Galaxy ◽  
Cluster Systems ◽  
Cluster Mass ◽  
Formation And Evolution ◽  
Globular Cluster System

AbstractThis paper reviews some of the observational properties of globular cluster systems, with a particular focus on those that constrain and inform models of the formation and dynamical evolution of globular cluster systems. I first discuss the observational determination of the globular cluster luminosity and mass function. I show results from new very deep HST data on the M87 globular cluster system, and discuss how these constrain models of evaporation and the dynamical evolution of globular clusters. The second subject of this review is the question of how to account for the observed constancy of the globular cluster mass function with distance from the center of the host galaxy. The problem is that a radial trend is expected for isotropic cluster orbits, and while the orbits are observed to be roughly isotropic, no radial trend in the globular cluster system is observed. I review three extant proposals to account for this, and discuss observations and calculations that might determine which of these is most correct. The final subject is the origin of the very weak mass-radius relation observed for globular clusters. I discuss how this strongly constrains how globular clusters form and evolve. I also note that the only viable current proposal to account for the observed weak mass-radius relation naturally effects the globular cluster mass function, and that these two problems may be closely related.

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 The Globular Cluster System of M87

1995 ◽  
Vol 164 ◽  
pp. 441-442
Author(s):  
J.G. Cohen
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Matter Content ◽  
Cluster System ◽  
Cluster Systems ◽  
Galaxy Halos ◽  
Resolution Imaging ◽  
Globular Cluster System ◽  
Imaging Spectrograph ◽  
Parent Galaxy

We have begun a program with the Low Resolution Imaging Spectrograph, operating with 30 multi-slits per exposure (Oke et al 1994, Cohen et al 1993) on the ten – meter W. M. Keck telescope located on Mauna Kea, Hawaii to observe the globular cluster systems of the Virgo ellipticals. We expect to learn about the dark matter content of galaxy halos, the formation of these halos and their cluster systems, possibly the formation of the galaxy's themselves, the interaction of the cluster system with the galaxy's gravitational potential (i.e. rotation and spinup), and the homogeneity of chemical evolution in various places. The metallicity of the globular clusters versus the metallicity of the underlying galaxy can also by analyzed. In addition the dynamics (i.e. in practice, the rotation and velocity dispersion) of the halo of the parent galaxy versus the globular cluster system can be determined.

scholarly journals Metal-rich and Metal-poor Globular Clusters in Ellipticals: Did we Learn Anything? or Constraints on Galaxy Formation and Evolution from Globular Cluster Sub-populations

2002 ◽  
Vol 207 ◽  
pp. 207-217
Author(s):  
Markus Kissler-Patig
Keyword(s):  
Galaxy Formation ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Historical Context ◽  
Cluster System ◽  
System Formation ◽  
Galaxy Formation And Evolution ◽  
Formation And Evolution ◽  
Globular Cluster System

A brief review on globular cluster sub-populations in galaxies, and their constraints on galaxy formation and evolution is given. The metal-poor and metal-rich sub-populations are put in a historical context, and their properties, as known to date, are summarized. We review why the study of these sub-populations is extremely useful for the study of galaxy formation and evolution, but highlight a few caveats with the current interpretations. We re-visit the current globular cluster system formation scenarios and show how they boil down to a single scenario for the metal-poor clusters (namely the formation in “universal”, small fragments at high z) and that a hierarchical formation seems favored for the metal-rich clusters.

scholarly journals A new era for the globular cluster system in M31

2009 ◽  
Vol 5 (S266) ◽  
pp. 117-122
Author(s):  
Myung Gyoon Lee ◽  
Sang Chul Kim ◽  
Ho Seong Hwang ◽  
Hong Soo Park ◽  
Doug Geisler ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Cluster System ◽  
Entire Body ◽  
Wide Field ◽  
Chemical Abundance ◽  
New Era ◽  
Group A ◽  
Formation And Evolution ◽  
Globular Cluster System

AbstractThe globular cluster system in M31 is an ideal laboratory for studying the formation and evolution of M31 as well as the globular clusters themselves. There have been numerous surveys and studies of the globular clusters in M31. However, only recently has the entire body of M31 been searched for globular clusters using wide-field CCD images by our group. A new era for the M31 globular cluster system has begun with the advent of wide-field CCD surveys of M31. We have discovered more than 100 new globular clusters in M31. Our catalog currently includes more than 500 globular clusters confirmed either based on spectra or HST images, many more than in the Milky Way. We present the structure, kinematics and chemical abundance of the M31 globular cluster system based on this large sample, and the implications for the formation and evolution of M31.

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 Globular Clusters as Probes of the Formation History of Elliptical Galaxies: Results for NGC 4472

2002 ◽  
Vol 207 ◽  
pp. 333-335
Author(s):  
K.L. Rhode ◽  
S.E. Zepf
Keyword(s):  
Galaxy Formation ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Spiral Galaxies ◽  
Elliptical Galaxy ◽  
Elliptical Galaxies ◽  
Cluster Systems ◽  
Large Sample ◽  
Formation History ◽  
History Of

We have undertaken a survey of the globular cluster systems of a large sample of elliptical and spiral galaxies in order to test predictions of elliptical galaxy formation models. Here we outline the survey and present a summary of our results for the Virgo elliptical NGC 4472.

scholarly journals THE GLOBULAR CLUSTER SYSTEM OF NGC 4636 AND FORMATION OF GLOBULAR CLUSTERS IN GIANT ELLIPTICAL GALAXIES

2012 ◽  
Vol 759 (2) ◽  
pp. 116 ◽  
Author(s):  
Hong Soo Park ◽  
Myung Gyoon Lee ◽  
Ho Seong Hwang ◽  
Sang Chul Kim ◽  
Nobuo Arimoto ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Elliptical Galaxies ◽  
Cluster System ◽  
Globular Cluster System

scholarly journals The Globular Cluster System of NGC 5128: Ages, Metallicities, Kinematics and Structural Parameters

2010 ◽  
Vol 27 (4) ◽  
pp. 379-389 ◽  
Author(s):  
K. A. Woodley ◽  
M. Gómez
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Structural Parameters ◽  
Cluster System ◽  
High Signal ◽  
Galactocentric Distance ◽  
Noise Spectroscopy ◽  
Formation And Evolution ◽  
Globular Cluster System ◽  
Cluster Age

AbstractWe review our recent studies of the globular cluster system of NGC 5128. First, we have obtained low-resolution, high signal-to-noise spectroscopy of 72 globular clusters using Gemini-S/GMOS to obtain the ages, metallicities, and the level of alpha enrichment of the metal-poor and metal-rich globular cluster subpopulations. Second, we have explored the rotational signature and velocity dispersion of the galaxy's halo using over 560 globular clusters with radial velocity measurements. We have also compared the dependence of these properties on galactocentric distance and globular cluster age and metallicity. Using globular clusters as tracer objects, we have analyzed the mass, and mass-to-light ratio of NGC 5128. Last, we have measured the structural parameters, such as half-light radii, of over 570 globular clusters from a superb 1.2-square-degree Magellan/IMACS image. We will present the findings of these studies and discuss the connection to the formation and evolution of NGC 5128.

scholarly journals Globular Cluster Systems of Elliptical Galaxies

1999 ◽  
Vol 186 ◽  
pp. 173-180
Author(s):  
Stephen E. Zepf ◽  
Keith M. Ashman
Keyword(s):  
Galaxy Formation ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Spiral Galaxies ◽  
Elliptical Galaxies ◽  
Cluster Systems ◽  
Physical Mechanisms ◽  
Cd Galaxies ◽  
Simplifying Assumptions ◽  
Poor Population

We review the observed properties of globular cluster systems and their implications for models of galaxy formation. Observations show that globular clusters form in gas-rich mergers, and that bimodal metallicity distributions are common in the globular cluster systems of ellipticals, with the metal-poor population more extended than the metal-rich one. These are three of the four predictions of the simple merger model of Ashman & Zepf (1992). The fourth prediction concerns the properties of the globular cluster systems of spirals, and is still to be tested by observation. Adopting Occam's razor, the confirmation of the fundamental predictions of the merger model from both young and old globular cluster systems is strong evidence that typical elliptical galaxies formed from the mergers of spiral galaxies. However, the simplifying assumptions of the Ashman-Zepf merger model limit its applicability to certain complex situations such as the formation of cD galaxies. We conclude this review by introducing new observational and theoretical programs that will further the understanding of the physical mechanisms of globular cluster and galaxy formation.

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