천문우주과학과

일시: 2023년 3월 22일 수요일 오후 4시 자4514호(세미나실)

연사: 오슬희 박사님(연세대학교)

제목: Galaxy Kinematics and 3D (IFU) spectroscopy   

초록: 

  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 AGN on the gas and stellar velocity dispersions (σ_gas and σ_star). σ_star (derived from absorption lines) tends to be higher than σ_gas (measured using emission lines), suggesting that stars are generally dynamically hotter than ionised gas. We find that the ratio of σ_gas and σ_∗ (Δσ = log σ_gas/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 (σ_broad) and the power sources: AGN shows a much higher σ_broad. Therefore, we conclude that gas kinematics is sensitive to the power sources, and AGN contributes to inflated gas velocity dispersions. 

관련 논문:

- The SAMI Galaxy Survey: decomposed stellar kinematics of galaxy bulges and disks (https://ui.adsabs.harvard.edu/abs/2020MNRAS.495.4638O/abstract)

- The SAMI Galaxy Survey: the difference between ionized gas and stellar velocity dispersions (https://ui.adsabs.harvard.edu/abs/2022MNRAS.512.1765O/abstract)