The Imprints Of Galactic Environment On Cluster Formation and Evolution

AbstractYoung star clusters (YSCs) appear to be a ubiquitous product of star formation in local galaxies, thus, they can be used to study the star formation process at work in their host galaxies. Moreover, YSCs are intrinsically brighter that single stars, potentially becoming the most important tracers of the recent star formation history in galaxies in the local Universe. In local galaxies, we also witness the presence of a large population of evolved star clusters, commonly called globular clusters (GCs). GCs peak formation history is very close to the redshift (z ~ 2) when the cosmic star formation history reached the maximum. Therefore, GCs are usually associated to extreme star formation episodes in high-redshift galaxies. It is yet not clear whether YSCs and GCs share a similar formation process (same physics under different interstellar medium conditions) and evolution process, and whether the former can be used as progenitor analogs of the latter. In this invited contribution, I review general properties of YSC populations in local galaxies. I will summarise some of the current open questions in the field, with particular emphasis to whether or not galactic environments, where YSCs form, leave imprints on the nested populations. The importance of this rapidly developing field can be crucial in understanding GC formation and possibly the galactic environment condition where this ancient population formed.

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From nuclear clusters to halo globulars: Star clusters as basic galactic building blocks

Proceedings of the International Astronomical Union ◽

10.1017/s1743921306005035 ◽

2006 ◽

Vol 2 (S235) ◽

pp. 48-51

Author(s):

Richard de Grijs

Keyword(s):

Star Formation ◽

Globular Clusters ◽

Star Clusters ◽

Galactic Nuclei ◽

Building Blocks ◽

Dominant Mode ◽

Star Formation History ◽

Formation Mode ◽

Formation History ◽

Nuclear Clusters

AbstractI assess the similarities and differences between the star-formation modes in quiescent spiral galaxies versus those in violent starburst regions, including galactic nuclei. As opposed to the quiescent star-formation mode, current empirical evidence on the star-formation processes in the extreme, high-pressure environments induced by galaxy encounters strongly suggests that star cluster formation is an important and perhaps even the dominant mode of star formation in such starburst events. This implies that by using star clusters as unique diagnostic probes, we can trace a galaxy's most violent star formation history very well, at least for the past few Gyr. The sizes, luminosities, and mass estimates of the young massive star clusters are entirely consistent with what is expected for young Milky Way-type globular clusters (GCs). Recent evidence lends support to the scenario that GCs, which were once thought to be the oldest building blocks of galaxies, are still forming today.

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Young Star Clusters: Metallicity Tracers in External Galaxies

Highlights of Astronomy ◽

10.1017/s1539299600017354 ◽

2005 ◽

Vol 13 ◽

pp. 667-669

Author(s):

Peter Anders ◽

Uta Fritze – v. Alvensleben ◽

Richard de Grijs

Keyword(s):

Star Formation ◽

Cluster Formation ◽

Star Clusters ◽

Young Star ◽

Interacting Galaxies ◽

Star Formation History ◽

Host Galaxy ◽

Chemical Enrichment ◽

Major Mode ◽

First Results

AbstractStar cluster formation is a major mode of star formation in the extreme conditions of interacting galaxies and violent star bursts. These newly-formed clusters are built from recycled gas, pre-enriched to various levels within the interacting galaxies. Hence, star clusters of different ages represent a fossil record of the chemical enrichment history of their host galaxy, as well as of the host galaxy’s violent star formation history. We present a new set of evolutionary synthesis models of our GALEV code, specifically developed to include the gaseous emission of presently forming star clusters, and a new tool to analyze multi-color observations with our models. First results for newly-born clusters in the dwarf star-burst galaxy NGC 1569 are presented.

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Young Star Clusters: Progenitors of Globular Clusters!?

Highlights of Astronomy ◽

10.1017/s1539299600015987 ◽

2005 ◽

Vol 13 ◽

pp. 366-368

Author(s):

Peter Anders ◽

Uta Fritze – v. Alvensleben ◽

Richard de Grijs

Keyword(s):

Star Formation ◽

Globular Clusters ◽

Star Clusters ◽

Young Star ◽

Star Cluster ◽

Star Formation History ◽

Starburst Galaxy ◽

Major Mode ◽

Young Clusters ◽

Young Star Clusters

AbstractStar cluster formation is a major mode of star formation in the extreme conditions of interacting galaxies and violent starbursts. Young clusters are observed to form in a variety of such galaxies, a substantial number resembling the progenitors of globular clusters in mass and size, but with significantly enhanced metallicity. From studies of the metal-poor and metal-rich star cluster populations of galaxies, we can therefore learn about the violent star formation history of these galaxies, and eventually about galaxy formation and evolution. We present a new set of evolutionary synthesis models of our GALEV code, with special emphasis on the gaseous emission of presently forming star clusters, and a new tool to compare extensive model grids with multi-color broad-band observations to determine individual cluster masses, metallicities, ages and extinction values independently. First results for young star clusters in the dwarf starburst galaxy NGC 1569 are presented. The mass distributions determined for the young clusters give valuable input to dynamical star cluster system evolution models, regarding survival and destruction of clusters. We plan to investigate an age sequence of galaxy mergers to see dynamical destruction effects in process.

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Star and Globular Cluster Formation in Mergers

Symposium - International Astronomical Union ◽

10.1017/s0074180900232956 ◽

1996 ◽

Vol 171 ◽

pp. 376-376

Author(s):

Uta Fritze - v. Alvensleben

Keyword(s):

Star Formation ◽

Globular Cluster ◽

Globular Clusters ◽

Cluster Formation ◽

Star Clusters ◽

Young Star ◽

Evolutionary Synthesis ◽

Secondary Population ◽

Ngc 1275 ◽

Young Star Clusters

The high burst strengths and star formation efficiencies found with spectrophotmetric and chemical evolutionary synthesis for mergers of gas-rich spirals led us to expect the formation of a secondary population of globular clusters (GC) with enhanced metallicity (F. – v. A. & Gerhard 1994, A&A 285, 751 u.775). HST imaging of NGC 7252, NGC 4038/39 and NGC 1275 revealed rich populations of bright young star clusters (YSC).

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Dissecting the Formation Histories of Galaxies with Stellar Populations Models

Proceedings of the International Astronomical Union ◽

10.1017/s174392131000270x ◽

2009 ◽

Vol 5 (S262) ◽

pp. 153-163

Author(s):

Ivo Labbé

Keyword(s):

Star Formation ◽

Current Knowledge ◽

High Redshift ◽

Local Environment ◽

Stellar Populations ◽

Current Data ◽

Star Formation History ◽

Spectral Energy ◽

Formation History ◽

History Of

AbstractHow did galaxies evolve from primordial fluctuations to the well-ordered but diverse population of disk and elliptical galaxies that we observe today? Stellar populations synthesis models have become a crucial tool in addressing this question by helping us to interpret the spectral energy distributions of present-day galaxies and their high redshift progenitors in terms of fundamental characteristics such as stellar mass and age. I will review our current knowledge on the evolution of stellar populations in early- and late type galaxies at z < 1 and the tantalizing – but incomplete – view of the stellar populations in galaxies at 1 < z < 3, during the global peak of star formation. Despite great progress, many fundamental questions remain: what processes trigger episodes of galaxy-scale star formation and what quenches them? To what degree does the star formation history of galaxies depend on the merger history, (halo) mass, or local environment? I will discuss some of the challenges posed in interpreting current data and what improved results might be expected from new observational facilities in the near- and more distant future.

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Open, Massive and Globular Clusters — Part of the Same Family?

Symposium - International Astronomical Union ◽

10.1017/s0074180900224133 ◽

2002 ◽

Vol 207 ◽

pp. 421-427 ◽

Cited By ~ 4

Author(s):

Søren S. Larsen

Keyword(s):

Globular Clusters ◽

Cluster Formation ◽

Formation Rate ◽

Star Clusters ◽

Young Star ◽

Host Galaxy ◽

Host Galaxies ◽

Cluster Systems ◽

Physical Description ◽

Super Star Clusters

Populations of young star clusters show significant differences even among “normal” disk galaxies. In this contribution I discuss how properties of young cluster systems are related to those of their host galaxies, based on a recent study of clusters in a sample of 22 nearby spiral galaxies. Luminous young clusters similar to the “super” star clusters observed in starbursts and mergers exist in several of these galaxies, and it is found that the luminosity of the brightest star cluster as well as the specific luminosity of the cluster systems both correlate well with the host galaxy star formation rate. When considering star clusters in different environments the traditional distinction between “open”, “massive” and “globular” clusters breaks down, underscoring the need for a universal physical description of cluster formation.

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Modelling Stellar Populations at High Redshift

Proceedings of the International Astronomical Union ◽

10.1017/s174392131102268x ◽

2010 ◽

Vol 6 (S277) ◽

pp. 158-165

Author(s):

Claudia Maraston

Keyword(s):

Star Formation ◽

High Redshift ◽

Stellar Populations ◽

Star Formation History ◽

Population Modelling ◽

Massive Galaxies ◽

Star Forming ◽

Formation History ◽

Derived Properties ◽

Stellar Masses

AbstractStellar populations carry information about the formation of galaxies and their evolution up to the present epoch. A wealth of observational data are available nowadays, which are analysed with stellar population models in order to obtain key properties such as ages, star formation histories, stellar masses. Differences in the models and/or in the assumptions regarding the star formation history affect the derived properties as much as differences in the data. I shall review the interpretation of high-redshift galaxy data from a model perspective. While data quality dominates galaxy analysis at the highest possible redshifts (z > 5), population modelling effects play the major part at lower redshifts. In particular, I discuss the cases of both star-forming galaxies at the peak of the cosmic star formation history as well as passive galaxies at redshift below 1 that are often used as cosmological probes. Remarks on the bridge between low and high-z massive galaxies conclude the contribution.

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Modeling Formation of Globular Clusters: Beacons of Galactic Star Formation

Proceedings of the International Astronomical Union ◽

10.1017/s1743921311000676 ◽

2010 ◽

Vol 6 (S270) ◽

pp. 381-384

Author(s):

Oleg Y. Gnedin

Keyword(s):

Star Formation ◽

Galaxy Formation ◽

Globular Cluster ◽

Globular Clusters ◽

Cluster Formation ◽

Star Clusters ◽

Mass Function ◽

Giant Molecular Clouds ◽

Early Galaxies ◽

The Masses

AbstractModern hydrodynamic simulations of galaxy formation are able to predict accurately the rates and locations of the assembly of giant molecular clouds in early galaxies. These clouds could host star clusters with the masses and sizes of real globular clusters. I describe current state-of-the-art simulations aimed at understanding the origin of the cluster mass function and metallicity distribution. Metallicity bimodality of globular cluster systems appears to be a natural outcome of hierarchical formation and gradually declining fraction of cold gas in galaxies. Globular cluster formation was most prominent at redshifts z > 3, when massive star clusters may have contributed as much as 20% of all galactic star formation.

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