TY - JOUR
T1 - The SAMI survey
T2 - evidence for dynamical coupling of ionized gas and young stellar populations
AU - Foster, Caroline
AU - Vaughan, Sam
AU - Fraser-McKelvie, Amelia
AU - Brough, Sarah
AU - Bryant, Julia J.
AU - Croom, Scott M
AU - D’Eugenio, Francesco
AU - Groves, Brent
AU - Konstantopoulos, Iraklis S.
AU - López-Sánchez, Ángel R.
AU - Oh, Sree
AU - Owers, Matt S.
AU - Sweet, Sarah M.
AU - van de Sande, Jesse
AU - Wisnioski, Emily
AU - Yi, Sukyoung K
AU - Zovaro, Henry R. M.
PY - 2023/5/1
Y1 - 2023/5/1
N2 - We explore local and global dynamical differences between the kinematics of ionized gas and stars in a sample of galaxies from Data Release 3 of the SAMI Galaxy Survey. We find better agreement between local (i.e. comparing on a spaxel-to-spaxel basis) velocities and dispersion of gas and stars in younger systems as with previous work on the asymmetric drift in galaxies, suggesting that the dynamics of stars and ionized gas are initially coupled. The intrinsic scatter around the velocity and dispersion relations increases with increasing stellar age and mass, suggesting that subsequent mechanisms, such as internal processes, divergent star formation, and assembly histories, also play a role in setting and altering the dynamics of galaxies. The global (flux-weighted) dynamical support of older galaxies is hotter than in younger systems. We find that the ionized gas in galaxies is almost always dynamically colder than the stars with a steeper velocity gradient. In absolute terms, the local difference in velocity dispersion is more pronounced than the local difference in velocity, possibly reflecting inherent differences in the impact of turbulence, inflow and/or feedback on gas compared to stars. We suggest how these findings may be taken into account when comparing high and low redshift galaxy samples to infer dynamical evolution.
AB - We explore local and global dynamical differences between the kinematics of ionized gas and stars in a sample of galaxies from Data Release 3 of the SAMI Galaxy Survey. We find better agreement between local (i.e. comparing on a spaxel-to-spaxel basis) velocities and dispersion of gas and stars in younger systems as with previous work on the asymmetric drift in galaxies, suggesting that the dynamics of stars and ionized gas are initially coupled. The intrinsic scatter around the velocity and dispersion relations increases with increasing stellar age and mass, suggesting that subsequent mechanisms, such as internal processes, divergent star formation, and assembly histories, also play a role in setting and altering the dynamics of galaxies. The global (flux-weighted) dynamical support of older galaxies is hotter than in younger systems. We find that the ionized gas in galaxies is almost always dynamically colder than the stars with a steeper velocity gradient. In absolute terms, the local difference in velocity dispersion is more pronounced than the local difference in velocity, possibly reflecting inherent differences in the impact of turbulence, inflow and/or feedback on gas compared to stars. We suggest how these findings may be taken into account when comparing high and low redshift galaxy samples to infer dynamical evolution.
KW - galaxies: evolution
KW - galaxies: kinematics and dynamics
KW - galaxies: stellar content
UR - http://www.scopus.com/inward/record.url?scp=85150605882&partnerID=8YFLogxK
U2 - 10.1093/mnras/stad487
DO - 10.1093/mnras/stad487
M3 - Article
SN - 1365-2966
VL - 521
SP - 84
EP - 98
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 1
ER -