Page History
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Title: Dynamically cold disks in the early Universe: myth or reality?
Speaker: Yixian
Summary:
- This paper used mock observations of CII and Ha based on SERRA simulations to study the kinematics of star-forming galaxies with M* > 10^8 M_sun at z~4-9, in particular focusing on the velocity to dispersion ratios (V/sigma).
- Regarding
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the differences between the kinematics of CII and Ha, the authors found that the sigma from Ha increases with M* steeper than the sigma from CII. They attribute the higher sigma of Ha to the inclusion of
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extraplanar ionized gas that may be due to outflows.
- They reported that ~60% of
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the whole sample of 3218 galaxies are dynamically cold disks, with V/sigma from CII between 4-10.
- Surprisingly, they did not find any evolution of V/sigma from both tracers with redshift from z~4-9 (see the figure). Their V/sigma of CII looks higher than the majority of the CII observations (triangles) for z > 5, although they attribute that to the overestimated sigma from the real but low-resolution observations. Their V/sigma from Ha are also higher than the observations (square symbols), and the TNG50 simulations at z ~5.
Title: MALS discovery of a rare HI 21-cm absorber at z∼1.35: origin of the absorbing gas in powerful AGN
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