세종대학교 두드림 비교과통합관리시스템

물리천문학과 콜로퀴움

‧강연 제목 : Galaxy Kinematics and 3D (IFU) spectroscopy

‧연사 : 연세대 천문우주학과 오슬희 박사님

‧일시 : 2023년 05월 3일 (수요일) 17:00~18:30

‧진행 방법 : 영601호

‧신청 가능 대상 : 세종대학교 재학생 누구나

‧신청기간 : 05월 2일 ~ 3일

‧강의 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 (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.