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Facultad de Ciencias Astronómicas y Geofísicas - Universidad Nacional de La Plata
Globular Clusters

Research group on

Globular Clusters and Dwarf Galaxies

Dwarf Galaxies


La Plata Astronomical Observatory


Goals


One main challenge in modern Astrophysics is to understand the formation and evolution of galaxies. Very intense activity, aimed at revealing which ingredients and processes led to the great variety of galaxies that we can observe now, is carried out by researchers all along the world.
The keys seem to lie within clusters of galaxies, where ellipticals, spirals, and irregulars are found; interactions between galaxies have surely played an important role in their evolutive histories.

Globular Clusters (GC) and Dwarf Galaxies (DG) are the simplest and most numerous stellar systems that populate these environments, hence their importance is fundamental for tracing the dynamical and chemical evolution that galaxies underwent along the whole age of the Universe.
Both GCs and DGs have been considered as building blocks to form larger galaxies, and, at the same time, as possible by-products of collisions and mergers of galaxies.

The GC - DG connection goes beyond this, involving their stellar populations: both types of systems are composed mainly by old stars, with a moderately low content of heavy elements. Regarding their structure, many GCs could have been formerly the nuclei of "stripped" DGs, after their interaction with larger galaxies.

The simultaneous study of both GCs and DGs is thus necessary to understand the processes that take place within clusters of galaxies. In this sense, our team has studied Milky Way globulars, as well as GC systems and DGs in the Fornax Cluster and other groups of galaxies, by means of polarimetry, surface photometry, mid-resolution spectroscopy, and theoretical models.
Our results have been published in about 35 papers in international refereed journals, which have got more than 800 cites in the scientific literature.
Presently, the Observatorio Astronómico de La Plata "Globular Clusters and Dwarf Galaxies Team" is at a development stage, with the incorporation of new researchers and new observational techniques; this will allow us to enlarge the outreach of our activities.

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Globular Clusters

47 Tuc Globular Clusters are usually considered as the most elemental stellar systems; they are dynamically simple and their stellar populations are homogeneous both in age and in chemical composition. Their study is thus a basic tool to understand the evolutive history of our Galaxy. Similarly, extragalactic globular clusters systems play a key role in the study of the formation of galaxies and clusters of galaxies.
On the other hand, in spite of their apparent simplicity, globular clusters hold still unanswered questions: X-ray sources, millisecond pulsars, nebular material, "blue stragglers", etc.

In recent years, our team performed a strong activity within this subject, particularly studying the interstellar material within Galactic globular clusters, and the metallicity distribution in extragalactic globular clusters systems.
The study of extragalactic globular clusters systems is closely related to that of dwarf galaxies. Our studies of the Fornax Cluster aim at building a general framework including the properties of both type of objects.

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Dwarf Galaxies

NGC5044-N153 Because of their relatively small sizes and masses, Dwarf Galaxies are key objects to study the global mechanisms that rule the formation and evolution of stellar systems. On the other hand, being by far the most numerous type of galaxy within groups and clusters of galaxies, dwarfs are main characters in the interactions, captures, and mergers that, we believe, were the origin of the different galaxy types that we observe today.

Our team has studied the morphological and evolutive properties of dwarf galaxies within the Fornax Cluster and the NGC 5044 Group.
The study of dwarf galaxies is connected with that of extragalactic globular clusters systems. Our studies of the Fornax Cluster aim at building a general framework including the properties of both type of objects.

Publications

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