scholarly journals Globular clusters in the Fornax cluster: A report from the FDS survey

2019 ◽  
Vol 14 (S351) ◽  
pp. 68-71
Author(s):  
Michele Cantiello ◽  
A. Venhola ◽  
M. Paolillo ◽  
R. D’Abrusco ◽  
A. Grado ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Accurate Determination ◽  
Galaxy Interactions ◽  
The Galaxy ◽  
The Status ◽  
Deep Survey ◽  
Dimensional Distribution ◽  
Fornax Cluster ◽  
Galaxy Luminosity Function

AbstractThe Fornax Deep Survey (FDS) is a multi-band imaging survey of the Fornax cluster of galaxies, executed with the ESO VLT Survey Telescope (VST). The survey is designed to reach unprecedented surface brightness and point-source magnitude depth over one virial radius of the cluster. The scientific objectives of the survey are numerous: the study of the galaxy luminosity function, derivation of galaxy scaling relations, determination of the properties of compact stellar systems, an accurate determination of distances and 3-D geometry of the Fornax cluster, analysis of diffuse stellar light and galaxy interactions, etc.In this contribute we give an overview on the interest of the survey on globular clusters (GC) populations, and present a report the status of the study of GCs also providing some preliminary results of our analysis, with particular regard to the two-dimensional distribution of GC candidates over ∼20 sq. degree area of Fornax centered on NGC 1399.

scholarly journals The Fornax Deep Survey with the VST

2019 ◽  
Vol 623 ◽  
pp. A1 ◽  
Author(s):  
E. Iodice ◽  
M. Spavone ◽  
M. Capaccioli ◽  
R. F. Peletier ◽  
G. van de Ven ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Surface Brightness ◽  
Major Axis ◽  
Position Angle ◽  
Early Type ◽  
Semi Major Axis ◽  
Cluster Galaxies ◽  
The Galaxy ◽  
Deep Survey ◽  
Fornax Cluster

Context. This paper is based on the multi-band (ugri) Fornax Deep Survey (FDS) with the VLT Survey Telescope (VST). We study bright early-type galaxies (mB ≤ 15 mag) in the 9 square degrees around the core of the Fornax cluster, which covers the virial radius (Rvir  ∼ 0.7 Mpc). Aims. The main goal of the present work is to provide an analysis of the light distribution for all galaxies out to unprecedented limits (in radius and surface brightness) and to release the main products resulting from this analysis in all FDS bands. We give an initial comprehensive view of the galaxy structure and evolution as a function of the cluster environment. Methods. From the isophote fit, we derived the azimuthally averaged surface brightness profiles, the position angle, and ellipticity profiles as a function of the semi-major axis. In each band, we derived the total magnitudes, effective radii, integrated colours, and stellar mass-to-light ratios. Results. The long integration times, the arcsec-level angular resolution of OmegaCam at VST, and the large covered area of FDS allow us to map the light and colour distributions out to large galactocentric distances (up to about 10−15 Re) and surface brightness levels beyond μr = 27 mag arcsec−2 (μB ≥ 28 mag arcsec−2). Therefore, the new FDS data allow us to explore in great detail the morphology and structure of cluster galaxies out to the region of the stellar halo. The analysis presented in this paper allows us to study how the structure of galaxies and the stellar population content vary with the distance from the cluster centre. In addition to the intra-cluster features detected in previous FDS works, we found a new faint filament between FCC 143 and FCC 147, suggesting an ongoing interaction. Conclusions. The observations suggest that the Fornax cluster is not completely relaxed inside the virial radius. The bulk of the gravitational interactions between galaxies happens in the W-NW core region of the cluster, where most of the bright early-type galaxies are located and where the intra-cluster baryons (diffuse light and globular clusters) are found. We suggest that the W-NW sub-clump of galaxies results from an infalling group onto the cluster, which has modified the structure of the galaxy outskirts (making asymmetric stellar halos) and has produced the intra-cluster baryons (ICL and GCs), concentrated in this region of the cluster.

scholarly journals A New Survey of Globular Cluster Structural and Luminosity Parameters

1988 ◽  
Vol 126 ◽  
pp. 489-490
Author(s):  
B. Cameron Reed ◽  
Charles J. Peterson
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Structural Parameters ◽  
Accurate Determination ◽  
Simplex Algorithm ◽  
Photoelectric Photometry ◽  
Central Surface ◽  
The Galaxy ◽  
Photometric Measurements

We have made an analysis of the visual photometric data contained in the Catalogue of Concentric Aperture UBVRI Photoelectric Photometry of Globular Clusters (Peterson 1986). Structural parameters have been obtained by use of the Simplex algorithm of Caceci and Cacheris (1984) to fit the model curves of King (1966) to the run of cluster luminosity with radius. We find that concentric aperture photometry alone can be used to determine globular cluster core radii and central surface brigtnesses reliably. Application of this techique, however, is limited to about two-thirds of the known clusters of the Galaxy because no or inadequate numbers of photometric measurements exist for the remaining clusters. Accurate determination of cluster concentration classes still requires use of other types of data, such as star counts.

scholarly journals Microarcsec Astrometry: The Gaia Mission

1998 ◽  
Vol 11 (1) ◽  
pp. 581-582
Author(s):  
L. Lindegren ◽  
M.A.C. Perryman
Keyword(s):  
Accurate Determination ◽  
Distance Measurements ◽  
Profound Impact ◽  
Individual Stars ◽  
The Galaxy ◽  
Direct Distance ◽  
Scientific Potential ◽  
Space Astrometry ◽  
Small Instrument

The Hipparcos mission demonstrated the efficiency of space astrometry (in terms of number of objects, accuracy, and uniformity of results) and the fact that a relatively small instrument can have a very large scientific potential in the area of astrometry. However, Hipparcos could probe less than 0.1 per cent of the volume of the Galaxy by direct distance measurements. Using a larger instrument and more efficient detectors, it is now technically feasible to increase the efficiency of a space astrometry mission by several orders of magnitude, thus encompassing a large part of the Galaxy within its horizon for accurate determination of parallaxes and transverse velocities. Such a mission will have immediate and profound impact in the areas of the physics and evolution of individual stars and of the Galaxy as a whole.

scholarly journals Orbits of Galactic Globular Clusters from Schmidt Plate Astrometry

1994 ◽  
Vol 161 ◽  
pp. 453-459 ◽  
Author(s):  
M. Odenkirchen ◽  
R.-D. Scholz ◽  
M.J. Irwin
Keyword(s):  
Globular Clusters ◽  
Proper Motions ◽  
Mass Model ◽  
Orbital Parameters ◽  
The Galaxy ◽  
Galactic Globular Clusters

We present results from orbit integrations for the globular clusters M 3 and M 92. Absolute proper motions recently measured from Tautenburg Schmidt plates and a three-component mass model for the Galaxy have been used to derive the galactic orbits of these clusters. Orbital parameters and the influence of observational uncertainties on the determination of the orbits are discussed.

scholarly journals CCD Photometry in the Core of the Fornax Dwarf Galaxy

1988 ◽  
Vol 126 ◽  
pp. 583-584
Author(s):  
Robert M. Light ◽  
P. Seitzer
Keyword(s):  
Globular Clusters ◽  
Stellar Population ◽  
Dwarf Galaxy ◽  
Field Population ◽  
Ccd Photometry ◽  
The Core ◽  
The Galaxy ◽  
Good Determination ◽  
Giant Branch Stars

The present study is concerned with the examination of properties of stars in the core of the Fornax dwarf spheroidal galaxy. Previous studies have shown that Fornax has a very diverse stellar population. Four of the globular clusters associated with Fornax were found to have metallicities significantly lower than the mean metallicity of the field population of the galaxy (Buonanno et al. 1985); these clusters point out an older, metal-poor population. Also, there are a number of luminous carbon stars, which are indicative of a much younger population (see Mould and Aaronson 1986). Studies of the field population of Fornax (Demers, Kunkel, and Hardy, 1979; Buonanno et al., 1985) have shown a dispersion in metallicity. We have measured a large sample of giant branch stars, enabling a good determination of mean properties of the Fornax stellar population, as well as allowing a comparison of stars as a function of distance from the center of Fornax.

scholarly journals Red Giants in Globular Clusters and Large-Scale Variations in The Galaxy

1980 ◽  
Vol 5 ◽  
pp. 817-826
Author(s):  
B. E. J. Pagel
Keyword(s):  
Recent Work ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Large Scale ◽  
Red Giants ◽  
Mixing Effects ◽  
The Galaxy ◽  
Metal Abundance ◽  
Red Giant

SummaryThis review concerns recent work on the determination of overall metallicities [Fe/H] in a number of globular clusters and the systematics of mixing effects displayed (usually) by weak CH and strong CN. Special attention is given to the globular cluster ω Centauri, where both metal abundance variations and mixing effects occur and are closely intertwined. Recent observations carried out at the Anglo-Australian Telescope by E.A. Mallia and D.C. Watts have revealed large variations in the strength of metallic lines across the red giant branch of this cluster.

scholarly journals The Status of Absolute Proper Motions and the Kinematics of Globular Clusters

1995 ◽  
Vol 164 ◽  
pp. 406-406 ◽  
Author(s):  
M. Geffert ◽  
B. Dauphole ◽  
J. Colin ◽  
M. Odenkirchen ◽  
H.-J. Tucholke ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Radial Velocities ◽  
Proper Motions ◽  
Preliminary Results ◽  
Space Motion ◽  
The Status ◽  
Galactic Potentials ◽  
Total Energies

We have studied a sample of 26 globular clusters for which so far absolute proper motions exist in the literature. The proper motions were combined with distances and radial velocities for a determination of the space motion of the clusters. Using different galactic potentials (see Dauphole & Colin 1994 and references therein) we calculated the orbits of the globular clusters and their time averaged eccentricities, total energies, and apo- and perigalactic distances. The relation of the orbital quantities to the metallicities of the globular clusters has been studied. Preliminary results of this study were presented in Geffert et al. (1993).

scholarly journals The Fornax 3D project: Globular clusters tracing kinematics and metallicities

2020 ◽  
Vol 637 ◽  
pp. A26 ◽  
Author(s):  
K. Fahrion ◽  
M. Lyubenova ◽  
M. Hilker ◽  
G. van de Ven ◽  
J. Falcón-Barroso ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
Globular Clusters ◽  
Spectroscopic Studies ◽  
Host Galaxy ◽  
Massive Galaxies ◽  
The Galaxy ◽  
Stellar Body ◽  
Galaxy Assembly ◽  
Fossil Records ◽  
Fornax Cluster

Globular clusters (GCs) are found ubiquitously in massive galaxies and due to their old ages, they are regarded as fossil records of galaxy evolution. Spectroscopic studies of GC systems are often limited to the outskirts of galaxies, where GCs stand out against the galaxy background and serve as bright tracers of galaxy assembly. In this work, we use the capabilities of the Multi Unit Explorer Spectrograph (MUSE) to extract a spectroscopic sample of 722 GCs in the inner regions (≲3 Reff) of 32 galaxies in the Fornax cluster. These galaxies were observed as part of the Fornax 3D project, a MUSE survey that targets early and late-type galaxies within the virial radius of Fornax. After accounting for the galaxy background in the GC spectra, we extracted line-of-sight velocities and determined metallicities of a sub-sample of 238 GCs. We found signatures of rotation within GC systems, and comparing the GC kinematics and that of the stellar body shows that the GCs trace the spheroid of the galaxies. While the red GCs prove to closely follow the metallicity profile of the host galaxy, the blue GCs show a large spread of metallicities but they are generally more metal-poor than the host.

scholarly journals A Robust Technique for Estimating Cosmological Parameters

2005 ◽  
Vol 201 ◽  
pp. 467-468
Author(s):  
Martin A. Hendry ◽  
Stéphane Rauzy
Keyword(s):  
Luminosity Function ◽  
Spatial Clustering ◽  
Cosmological Parameters ◽  
Bias Parameter ◽  
Galaxy Surveys ◽  
The Galaxy ◽  
Distance Data ◽  
Galaxy Luminosity Function

We present a new ROBUST technique for extracting information from galaxy surveys which allows determination of cosmological parameters free of almost any model assumptions concerning the galaxy luminosity function and spatial clustering. We illustrate ROBUST by estimating H0 and the linear bias parameter, β, from recent redshift-distance data.

scholarly journals Resolving Globular Clusters in the Fornax Cluster and Beyond

2002 ◽  
Vol 207 ◽  
pp. 327-329
Author(s):  
Carl J. Grillmair ◽  
Jon Holtzman ◽  
Rebecca Elson
Keyword(s):  
Globular Clusters ◽  
Structural Parameters ◽  
Stellar Clusters ◽  
Early Type ◽  
Minimization Method ◽  
Luminosity Functions ◽  
Fornax Cluster ◽  
Structure Spectrum

We describe an ongoing program to measure structural parameters for globular clusters with a range of ages in early-type galaxies. Using deep, optimally-dithered HST WFPC2 observations of NGC 3597, NGC 1316, and NGC 1399, we apply a χ2 minimization method to the determination of cluster sizes. The goals include studying the structure spectrum of stellar clusters at birth, and determining the rate at which tidal and evaporative destruction mechanisms operate to alter luminosity functions and specific frequencies to what we see in ellipticals today.

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