The central region of the Fornax cluster

Hilker, M.; Infante, L.; Vieira, G.; Kissler-Patig, M.; Richtler, T.

doi:10.1051/aas:1999434

Cited by 245 publications

(282 citation statements)

References 23 publications

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“…It is worth mentioning, however, that they are well worth a study on their own, because they contain important clues for the GCLF formation and overall shape (see the discussions by McLaughlin 1994;Richtler 2003Richtler , 2006, and because they represent a link between the star clusters and the so-called Ultra Compact Galaxies or Dwarf-Galaxy Transition Objects (Hilker et al 1999;Haşegan et al 2005;Rejkuba et al 2007;Mieske et al 2002Mieske et al , 2008.…”

Section: A Historical Notementioning

confidence: 99%

Globular cluster luminosity function as distance indicator

Rejkuba¹

2012

Astrophys Space Sci

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Globular cluster luminosity function as distance indicatorM. Rejkuba 1 Globular clusters are among the first objects used to establish the distance scale of the Universe. In the 1970-ies it has been recognized that the differential magnitude distribution of old globular clusters is very similar in different galaxies presenting a peak at M V ∼ −7.5. This peak magnitude of the so-called Globular Cluster Luminosity Function has been then established as a secondary distance indicator. The intrinsic accuracy of the method has been estimated to be of the order of ∼ 0.2 mag, competitive with other distance determination methods. Lately the study of the Globular Cluster Systems has been used more as a tool for galaxy formation and evolution, and less so for distance determinations. Nevertheless, the collection of homogeneous and large datasets with the ACS on board HST presented new insights on the usefulness of the Globular Cluster Luminosity Function as distance indicator. I discuss here recent results based on observational and theoretical studies, which show that this distance indicator depends on complex physics of the cluster formation and dynamical evolution, and thus can have dependencies on Hubble type, environment and dynamical history of the host galaxy. While the corrections are often relatively small, they can amount to important systematic differences that make the Globular Cluster Luminosity Function a less accurate distance indicator with respect to some other standard candles.

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Section: A Historical Notementioning

confidence: 99%

Globular cluster luminosity function as distance indicator

Rejkuba¹

2012

Astrophys Space Sci

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“…7b demonstrates that for a large fraction of early-type galaxies only high-luminosity objects were considered. This is partly due to detection limits especially at large distances, but also due to the fact that since the discovery of UCDs in the Fornax Cluster by Hilker et al (1999) and Drinkwater et al (2000), much effort has been made to detect and to analyze EOs brighter than about M V = −10 mag, while fainter EOs were neither in the focus of UCD studies nor in those investigating GCs.…”

Section: Eos In Late-type Galaxiesmentioning

confidence: 99%

“…In recent years, hundreds of ECs have been detected in all types of galaxies ranging from dwarfs to giant elliptical galaxies. A&A 547, A65 (2012) Hilker et al (1999) and Drinkwater et al (2000) discovered in the Fornax Cluster compact objects with luminosities above the brightest known GCs and which were not resolved by ground-based observations. These objects have masses between a few 10 6 M and 10 8 M and effective radii between r eff = 10 and 100 pc.…”

Section: Introductionmentioning

confidence: 98%

A catalog of extended clusters and ultra-compact dwarf galaxies

Kroupa

2012

A&A

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Context. In the past decade, very extended old stellar clusters with masses in the range from a few 10 4 to 10 8 M and effective radii larger than 10 pc have been found in various types of galaxies in different environments. Objects with masses comparable to normal globular clusters (GCs) are called extended clusters (ECs), while objects with masses in the dwarf galaxy regime are called ultra-compact dwarf galaxies (UCDs). Aims. The paper analyses the observational parameters total luminosity, M V , effective radius, r eff , and projected distance to the host galaxy, R proj , of all known ECs and UCDs and the dependence of these parameters on the type and the total luminosity of their host galaxy. Methods. We searched the available literature to compile a catalog of star clusters with effective radii larger than 10 pc. As there is no clear distinction between ECs and UCDs, both types of objects will be called extended stellar objects -abbreviated "EOs" -in this paper.Results. In total, we found 813 EOs of which 171 are associated with late-type galaxies and 642 EOs associated with early-type galaxies. EOs cover a luminosity range from about M V = −4 to −14 mag. However, the vast majority of EOs brighter than M V = −10 mag are associated with giant elliptical galaxies. At each magnitude extended objects are found with effective radii between 10 pc and an upper size limit, which shows a clear trend: the more luminous the object the larger is the upper size limit. For EOs associated with early-and late-type galaxies, the EO luminosity functions peak at −6.40 mag and −6.47 mag, respectively, which is about one magnitude fainter than the peak of the GC luminosity function. EOs and GCs form a coherent structure in the r eff vs. M V parameter space, while there is a clear gap between EOs and early-type dwarf galaxies. However, there is a small potential overlap at the high-mass end, where the most extended EOs are close to the parameters of some compact elliptical galaxies. We compare the EO sample with the numerical models of a previous paper and conclude that the parameters of the EO sample as a whole can be very well explained by a star cluster origin, where EOs are the results of merged star clusters of cluster complexes.

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“…Ultra-compact dwarfs (UCDs) are massive but compact gravitationallybound stellar systems discovered in the nearby Fornax [1][2] [3][4] [5] and Virgo [6] galaxy clusters. Several UCD formation theories have emerged -that they are ultra-massive examples of globular clusters (GCs) [4]; or stellar superclusters created in gas-rich galaxy mergers [7]; or the remnant cores of tidallystripped nucleated dwarf galaxies [8].…”

Section: Observing the Ucd/gc Interfacementioning

confidence: 99%