What do globular clusters tell us about isolated ellipticals? The case of NGC 6411

2019 ◽  
Vol 14 (S351) ◽  
pp. 60-63
Author(s):  
J. P. Caso ◽  
Lilia P. Bassino ◽  
T. Richtler ◽  
R. Salinas
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Luminosity Function ◽  
Elliptical Galaxy ◽  
Cluster System ◽  
Colour Distribution ◽  
Globular Cluster System

AbstractWe summarize the results from a study of the globular cluster (GC) system of the isolated elliptical galaxy NGC 6411, based on Gemini/GMOS g', r', i’ photometry. The extent of the globular cluster system is about 70 kpc. It contains ≍700 members. The colour distribution and luminosity function are typical of old GC systems. An excess of bright GCs with intermediate colours might evidence an intermediate-age merger.

scholarly journals A Gemini/GMOS study of the bright elliptical galaxy NGC 3613 and its globular cluster system

2020 ◽  
Vol 492 (3) ◽  
pp. 4313-4324 ◽  
Author(s):  
Bruno J De Bórtoli ◽  
Lilia P Bassino ◽  
Juan P Caso ◽  
Ana I Ennis
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Elliptical Galaxy ◽  
Small Sample ◽  
Cluster System ◽  
Host Galaxy ◽  
Surface Photometry ◽  
Host Galaxies ◽  
Colour Distribution ◽  
Globular Cluster System

ABSTRACT We present the first photometric study of the globular cluster system (GCS) of the E galaxy NGC 3613 (MV = −21.5, d ∼ 30.1 Mpc), as well as the surface photometry of the host galaxy, based on Gemini/GMOS images. Being considered the central galaxy of a group, NGC 3613 inhabits a low-density environment although its intrinsic brightness is similar to the expected one for galaxies in the centre of clusters. The following characteristics are obtained for this GCS. The colour distribution is bimodal, with metal-poor globular clusters (GCs) getting slightly bluer with increasing radius. The radial and azimuthal projected distributions show that metal-rich GCs are more concentrated towards the host galaxy and trace its light distribution very precisely, while metal-poor GCs present a more extended and uniform distribution. The GC luminosity function helps validate the adopted distance. The estimated total GC population of Ntot = 2075 ± 130 leads to a specific frequency SN = 5.2 ± 0.7, a value within the expected range for GCSs with host galaxies of similar luminosity. The surface photometry of NGC 3613 reveals a three-component profile and a noticeable substructure. Finally, a small sample of ultracompact dwarf candidates are identified in the surroundings of the host galaxy.

Globular cluster system of NGC 3613, a massive elliptical galaxy in a poor environment

2019 ◽  
Vol 14 (S351) ◽  
pp. 84-88
Author(s):  
Bruno J. De Bórtoli ◽  
Lilia P. Bassino ◽  
Juan P. Caso ◽  
Ana I. Ennis
Keyword(s):  
Globular Cluster ◽  
Elliptical Galaxy ◽  
Cluster System ◽  
Host Galaxy ◽  
Low Density ◽  
Stellar Component ◽  
Magnitude Diagram ◽  
The Galaxy ◽  
Colour Distribution ◽  
Globular Cluster System

AbstractWe present an analysis of the globular cluster system (GCS) of the galaxy NGC 3613, an intrinsically bright elliptical galaxy (MV = −21.5) in a low density environment (it is the central galaxy of a group of a dozen galaxies). Based on Gemini/GMOS photometry of NGC 3613 we obtained the following properties for this GCS. A ‘blue tilt’ is detected in the colour-magnitude diagram. The colour distribution is bimodal, presenting the two classical globular cluster (GC) sub-populations. The spatial and azimuthal projected distributions show that red sub-population correlates with the stellar component of the host galaxy.

scholarly journals NGC 5128: The Giant Beneath

2010 ◽  
Vol 27 (4) ◽  
pp. 475-481 ◽  
Author(s):  
Gretchen L. H. Harris
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Stellar Population ◽  
Total Population ◽  
Elliptical Galaxy ◽  
Cluster System ◽  
Fundamental Plane ◽  
Galaxy Type ◽  
Globular Cluster System ◽  
Distance Indicators

AbstractThis paper reviews what has been learned about the old stellar population of NGC 5128, the only large elliptical galaxy close enough that we can currently observe individual stars as faint as the horizontal branch. Although its galaxy type is still a matter of debate, the uncertainties over distance are now largely resolved; comparison of five stellar distance indicators gives d= 3.8±0.1 Mpc. The globular cluster system, which was once perplexingly invisible, is now known to be predominantly old with a substantial metal-rich component. The globular cluster system (GCS) total population and luminosity function are normal and the clusters follow the same fundamental plane relation as those in the Milky Way and M31. Finally, the halo out to at least ∼7reff is dominated by metal-rich stars which are also predominantly old, with age and metallicity tantalizingly similar to the majority of globular clusters.

scholarly journals Ages and Metallicities of Globular Clusters in NGC 5128

2002 ◽  
Vol 207 ◽  
pp. 269-274 ◽  
Author(s):  
Enrico V. Held ◽  
Luciana Federici ◽  
Carla Cacciari ◽  
Vincenzo Testa
Keyword(s):  
Absorption Line ◽  
Globular Cluster ◽  
Hydrogen Absorption ◽  
Metal Content ◽  
Globular Clusters ◽  
Elliptical Galaxy ◽  
Cluster System ◽  
Globular Cluster System ◽  
Metallicity Distribution

We have obtained multislit spectroscopy of 40 known globular clusters in the nearby peculiar elliptical galaxy NGC 5128 at the ESO NTT telescope. Measurements of metal and hydrogen absorption line indices have been used to estimate the age and metal content of individual clusters. The results have been combined with previous data from multifibre spectroscopy of clusters in the halo of NGC 5128 to study the age and metallicity distribution of the globular cluster system.

scholarly journals Globular Cluster Systems: Comparison with the Milky Way

2002 ◽  
Vol 207 ◽  
pp. 68-72
Author(s):  
Dante Minniti
Keyword(s):  
Globular Cluster ◽  
Reference Point ◽  
Luminosity Function ◽  
Milky Way ◽  
Elliptical Galaxy ◽  
Cluster System ◽  
Cluster Systems ◽  
Distant Galaxies ◽  
Globular Cluster System

The Milky Way globular cluster system serves as a reference for the study of more distant galaxies. Here I stress that there are still things we do not know about the globular cluster system of our own galaxy: their total number, their spatial motions and distances, and their IR properties. If our best reference point is not fully known, caution should be exercised when interpreting observations of distant systems. At the same time, when studying distant ellipticals it is not always advisable to rely on the Milky Way as a comparison. For example, only recently the first full calibration of the luminosity function of the globular cluster system of an elliptical galaxy was made, necessary to compare apples with apples.

Metallicity and Luminosity Functions of the Globular Clusters in NGC 4472

1996 ◽  
Vol 174 ◽  
pp. 393-394
Author(s):  
Myung Gyoon Lee ◽  
Eunhyeuk Kim ◽  
Doug Geisler
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Elliptical Galaxy ◽  
Virgo Cluster ◽  
Cluster System ◽  
Luminosity Functions ◽  
Globular Cluster System

NGC 4472, the brightest elliptical galaxy in the Virgo cluster, has a rich globular cluster system. We present a study of the metallicity and luminosity functions of a large number of globular clusters in NGC 4472. Deep Washington CT1 photometry of a wide (16′ × 16′) field of NGC 4472 was obtained using Tek 2048 × 2048 CCD at the KPNO 4m telescope.

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.

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.

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