The formation of bars in massive disc galaxies

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The formation and evolution of disc galaxies is thought to consist essentially of two main phases. After the initial turbulent phase, when violent mergers with other galaxies play a major role, the disc of stars and gas settles in a more uniform configuration. After the disc settling, internal dynamical processes often lead to the formation of a bar in the disc, i.e., a significant number of stars begin to move in more eccentric orbits, forming the elongated bar. A number of theoretical studies shows that bars can form very easily in a stellar disc, either spontaneously or during interactions with other galaxies. Yet, about 30% of disc galaxies in the local Universe do not host a bar and this fraction was larger when the Universe was younger. We still do not fully understand why some disc galaxies remain unbarred and the main goal of this PhD project is to answer this question. Important clues may reside in how stars move in the discs of unbarred galaxies. This therefore calls for a study of the kinematics of stars and the ultimate origin of the gravitational forces that govern their movement.However, the scientific outcome of this project is not limited to our main question. Since dark matter haloes can also interfere with the formation of bars, the results of this investigation will shed light on the properties of dark matter in the Universe. In addition, we will investigate the properties of stellar populations at the ends of the bar with unprecedented physical spatial resolution, allowing us to study the formation of stellar structures such as spiral arms and galactic rings as never done before. This work will employ archival, state-of-the-art data from the integral-field spectrograph MUSE at the Very Large Telescope in Chile. It will be based on a suite of analyses to explore the kinematics, ages and chemical content of stars in a sample of tens of barred and unbarred galaxies in the local Universe (e.g., Gadotti et al. 2020; Bittner et al. 2020). Furthermore, we will use archival JWST data to assess the fraction and properties of barred galaxies at redshifts beyond z ~ 1, and compare these results with earlier studies that employed HST data. By making use of the JWST improved capabilities (as compared to HST) this study will consolidate our understanding on the evolution with redshift of the fraction and properties of barred galaxies (e.g., bar length and axial ratio).Working within an international team of researchers, the student will gain experience with large data sets, parallel computing, photometric analyses and spectral fitting techniques. Furthermore, they will have the opportunity to participate in (or lead) the writing of proposals for telescope time. If a proposal is successful, they may participate actively in the observations at the telescope in Chile or other observatory sites.