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04-05-2023
Colloquium: Cold gas dynamics in high-z galaxies
| Submitter: | Federico Lelli |
| Description: | Gas dynamics play a key role in our understanding of the formation and evolution of galaxies. At z=0, gas dynamics has been extensively studied using a variety of tracers, such as the emission lines of atomic gas (HI), molecular gas (CO), and ionized gas (H-alpha). At high z, the study of gas dynamics has been often restricted to warm ionized gas (H-alpha and [OIII] lines), but the advent of high-resolution ALMA observations opened up the possibility to trace cold neutral gas using CO, [CI] and [CII] lines. In this talk, I will present in-depth studies of individual galaxies at z=1-6 with ALMA data at resolutions of 0.05"-0.5". In such galaxies, the cold gas forms dynamically-cold rotation-supported disks with high rotation-to-dispersion ratios, in contrast to the common picture of "turbulent" high-z disks from H-alpha data. In most cases, the inner rotation curve of the galaxies requires the presence of a central mass concentration (a stellar bulge) in addition to a pure exponential disk. The existence of rotation-supported gas disks and stellar bulges up to z=6 suggest that massive galaxies must have formed and evolved surprisingly fast during the first billion years of the Universe's lifetime. |
| Copyright: | Federico Lelli |
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