G.A. Valk

Galaxies are the building blocks of the Universe. They are composed of stars, dust, and gas, embedded within a dark matter halo. We can find galaxies isolated (relatively) in the Universe, in the region known as “field”, or as part of gravitational associations of these objects, called groups and clusters. The properties of galaxies depend on their environments. In high-density environments, galaxies typically exhibit early-type morphologies (Elliptical and Lenticulars), lower star formation rates, less gas content, and are more redder than similar objects in the field. To explain these relationships between galaxies and their environments, several mechanisms are proposed in the literature. These mechanisms are associated with interactions between galaxies, between galaxies and the cluster potential, and between galaxies and the intra-cluster medium. One way to better understand the relative efficiency of these several mechanisms is through dynamic analyses, as these mechanisms act on different time and space scales. In this seminar, I will present the results obtained during my master’s degree, where I analyzed the spatial distribution, the velocity dispersion, and the velocity anisotropy profiles of four galaxy populations. The populations are defined with respect to the main ionizing source of the gas in the galaxy, or in the absence of ionized gas. As I will show, different populations exhibit different properties, and we can understand these differences in a scenario where the environmental mechanisms are affecting the galaxies.

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