Abstract
Lenticular (S0) galaxies occupy a pivotal position in the Hubble tuning fork diagram, connecting the branch of ellipticals with the branch of spirals, as they show structural characteristics of both. However, eighty years after their discovery the evolutionary mechanisms that shape these members of the galaxy zoo are relatively poorly understood and still subject to debate. Recent works using spectroscopic data have revealed that these galaxies show a duality in their physical properties (e.g., Coccato et al. 2022) suggesting that S0s follow, at least, two different formation paths depending on whether they are found in the low-density general field or in dense environments. Galaxy clusters are one of the cornerstones in this puzzle, as it is known that they may convert infalling spiral galaxies into lenticulars through hydrodynamical interactions, while the large peculiar velocities at which galaxies move in these large-scale structures disfavor alternative formation mechanisms involving gravity, like galaxy mergers. In addition, it is also possible that lenticular galaxies form within smaller groups and subclusters before they fall into a larger structure as part of a process known as preprocessing.
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In this work, the student will determine the distribution of the local population of S0 galaxies within the phase-space diagram of the groups and clusters identified in the SDSS Legacy catalog by Tempel et al. (2017). The main goal is to study the group/cluster membership of the different spectral populations of lenticular galaxies presented in Tous et al. (2020) and Tous et al. (2023) through the methodology introduced by Rhee et al. (2017) that allows distinguishing between ancient and recent infallers (see their fig. 6), to constrain the habitat of the different types of S0 galaxies and their formation paths.