Kinematics of galaxy bulges, disks, and ionised gas from 3D spectroscopy

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• Sree Oh (ANU)
• Friday 23 June 2023, 11:30-12:30
• Ryle seminar room + online.

If you have a question about this talk, please contact Sandro Tacchella.

The spatially-resolved kinematics of bulge and disk components from 3D spectroscopy describe how galaxies have a wide range of stellar kinematics according to galaxy types. Kinematic scaling relations demonstrate that the galaxy stellar mass scales with kinematics for both bulge and disk components of all galaxy types, which suggests kinematics of two components are less dependent on galaxy populations and largely determined by the mass. Our findings also suggest that the relative contributions of bulge and disk components explain, at least to first order, the complex kinematic behaviour of galaxies according to galaxy type. 3D spectroscopy also allows studying the impact of feedback processes on the gas and stellar velocity dispersions (σgas and σstar). σstar (derived from absorption lines) tends to be higher than σgas (measured using emission lines), suggesting that stars are generally dynamically hotter than ionised gas. We find that the ratio of σgas and σ∗ (Δσ = log σgas/σ∗) strongly correlates with the contribution of AGN , implying that AGN inflates gas velocity dispersions. One possibility is AGN -driven outflow. We confirm the impact of AGN on gas kinematics by fitting emission lines with broad and narrow components. Galaxies with broad component show inflated gas velocity dispersions than the prediction. Also, we find a tight correlation between the velocity dispersion of the broad component (σbroad) and the power sources: AGN shows a much higher σbroad. Therefore, we conclude that gas kinematics is sensitive to the power sources, and AGN contributes to inflated gas velocity dispersions.

This talk is part of the Galaxies Discussion Group series.

This talk is included in these lists:

• Cambridge Astronomy Talks
• Combined External Astrophysics Talks DAMTP
• Cosmology, Astrophysics and General Relativity
• Galaxies Discussion Group
• Institute of Astronomy Talk Lists
• Kavli Institute for Cosmology Talk Lists
• Ryle seminar room + online

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