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 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 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 Wide‐Field Survey of Globular Clusters in M31. II. Kinematics of the Globular Cluster System

2008 ◽  
Vol 674 (2) ◽  
pp. 886-908 ◽  
Author(s):  
Myung Gyoon Lee ◽  
Ho Seong Hwang ◽  
Sang Chul Kim ◽  
Hong Soo Park ◽  
Doug Geisler ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Field Survey ◽  
Cluster System ◽  
Wide Field ◽  
Globular Cluster System

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 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 Wide-field study of the peculiar globular cluster system hosted by the field lenticular NGC 1172

2020 ◽  
Vol 499 (2) ◽  
pp. 2554-2563
Author(s):  
Ana Inés Ennis ◽  
Juan Pablo Caso ◽  
Lilia P Bassino ◽  
Ricardo Salinas ◽  
Matías Gómez
Keyword(s):  
Field Study ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Hubble Space Telescope ◽  
Large Fraction ◽  
Cluster System ◽  
Wide Field ◽  
Full Extension ◽  
Specific Frequency ◽  
Globular Cluster System

ABSTRACT We present a wide-field study of the globular cluster system (GCS) of the field lenticular galaxy NGC 1172, based on observations from Gemini Multi-Object Spectrograph/Gemini (optical), FourStar/Magellan (NIR), and archival data from ACS/Hubble Space Telescope (optical). This analysis covers the full extension of the GCS, and results in a value of specific frequency (SN = 8.6 ± 1.5) peculiarly high for an intermediate-mass galaxy in a low-density environment such as this one. We find that the GCS appears to be bimodal, although the colour distribution is narrow and does not allow for an accurate separation of the subpopulations. However, the combination of optical and NIR filters allows us to obtain an estimation of the metallicity distribution based on the photometry, which supports bimodality. We conclude that the presence of a large fraction of metal-poor globular clusters (GCs) and the high specific frequency point to NGC 1172 having accreted a significant amount of GCs from low-mass satellites in the past.

scholarly journals The SLUGGS Survey: wide field imaging of the globular cluster system of NGC 4278

2013 ◽  
Vol 436 (2) ◽  
pp. 1172-1190 ◽  
Author(s):  
Christopher Usher ◽  
Duncan A. Forbes ◽  
Lee R. Spitler ◽  
Jean P. Brodie ◽  
Aaron J. Romanowsky ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Cluster System ◽  
Wide Field ◽  
Globular Cluster System ◽  
Field Imaging ◽  
Wide Field Imaging

Globular cluster tidal interactions and mergers in the Galactic disc

2019 ◽  
Vol 14 (S351) ◽  
pp. 442-446
Author(s):  
Alessandra Mastrobuono-Battisti ◽  
Sergey Khoperskov ◽  
Paola Di Matteo ◽  
Misha Haywood
Keyword(s):  
Globular Cluster ◽  
Iron Content ◽  
Globular Clusters ◽  
Dynamical Evolution ◽  
Stellar Populations ◽  
Cluster System ◽  
Galactic Disc ◽  
Tidal Interactions ◽  
Globular Cluster System ◽  
Shed Light

AbstractThe Galactic globular cluster system went and is still going through dynamical processes that require to be explored in detail. Here we illustrate how primordial massive globular clusters born in the Milky Way’s disc evolved by stripping material from each other or even merging very early during their lives. These processes might explain the puzzling presence of star-by-star spreads in iron content observed in massive globular clusters and should be taken into account when studying globular cluster stellar populations. In this context, we show how the direct comparison between the predictions provided by our direct N-body simulations and observations can shed light on the origin and chemo-dynamical evolution of globular clusters.

scholarly journals Deep Wide-Field Photometry of the NGC 5128 Globular Cluster System: A Progress Report

2002 ◽  
Vol 207 ◽  
pp. 309-311
Author(s):  
G. L. H. Harris ◽  
D. Geisler ◽  
W. E. Harris ◽  
J. E. Hesser
Keyword(s):  
Globular Cluster ◽  
Luminosity Function ◽  
Progress Report ◽  
Cluster System ◽  
Wide Field ◽  
Preliminary Results ◽  
System A ◽  
Globular Cluster System

We have obtained CMR photometry for a roughly 1° square region centered on NGC 5128. Preliminary results indicate that the limiting magnitude of the images is ≳ 1 magnitude fainter than the peak of the globular cluster luminosity function (GCLF) at R ⋍ 21.

scholarly journals An Overview of the Globular Cluster System of the Galaxy

1988 ◽  
Vol 126 ◽  
pp. 37-48
Author(s):  
Robert Zinn
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Milky Way ◽  
Galactic Center ◽  
Galactic Plane ◽  
Cluster System ◽  
Open Clusters ◽  
The Galaxy ◽  
Globular Cluster System ◽  
Harlow Shapley

Harlow Shapley (1918) used the positions of globular clusters in space to determine the dimensions of our Galaxy. His conclusion that the Sun does not lie near the center of the Galaxy is widely recognized as one of the most important astronomical discoveries of this century. Nearly as important, but much less publicized, was his realization that, unlike stars, open clusters, HII regions and planetary nebulae, globular clusters are not concentrated near the plane of the Milky Way. His data showed that the globular clusters are distributed over very large distances from the galactic plane and the galactic center. Ever since this discovery that the Galaxy has a vast halo containing globular clusters, it has been clear that these clusters are key objects for probing the evolution of the Galaxy. Later work, which showed that globular clusters are very old and, on average, very metal poor, underscored their importance. In the spirit of this research, which started with Shapley's, this review discusses the characteristics of the globular cluster system that have the most bearing on the evolution of the Galaxy.

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