Séminaire/Seminar Galaxies |
| « Early disc settling in Milky Way- like galaxies » |
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Camilla Nyhagen |
| Recent JWST and ALMA observations have given us insight into the gas properties of the ISM far into the Epoch of Reionization z > 6. The observations have shown surprising findings of galaxies with disc-like morphologies and high rotation-to-dispersion ratios (V /s > 10), which are properties often associated with more evolved galaxies in the local Universe. Theoretical models have indicated that the inferred kinematics is highly dependent on the gas tracers, and with multi-wavelength observations being available for only a handful of high-redshift systems, this hints towards the need of a multi-phase view of the ISM to understand what gas phases the disc is settling in. In this study, we explore the underlying physics that drives the early formation of dynamically cold (V /s ? 4), Milky Way-like disc galaxies and their high-redshift predecessors. To do this, we employ high-resolution cosmological zoom-in simulations from the VINTERGATAN and VINTERGATAN-GM suites, covering redshifts 0 < z < 9, which allows us to follow the formation, evolution and destruction of the discs. To connect the simulations to observable kinematic properties, we post-process the simulations using a combination of Ramses-RT and Cloudy to model key gas tracers such as CO(3-2), [CII] 158 µm, Ha and [OIII]88µm. Our results reveal the presence of disc-like structures and dynamically cold discs at z ? 4, with cold gas tracers such as CO(3-2) and [CII] 158 µm obtaining higher V /s values compared warmer tracers such as Ha and [OIII]88µm, which is a result of the strong dependency on gas tracers for the inferred velocity dispersion. We further investigate the ISM phases in which the discs manifest by comparing the evolution of M? - V /s for the different tracers. Finally, we also explore the effect of mergers, different modelling approaches and other mechanisms that affect the disc-kinematics at high redshifts and how they connect to lower redshifts. |
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jeudi 8 octobre 2026 - 11:30 Salle 281 Institut d'Astrophysique de Paris |
| Page web du séminaire / Seminar's webpage |