The SAMI galaxy survey:Mass and environment as independent drivers of galaxy dynamics

• Published in: Monthly Notices of the Royal Astronomical Society
• Main Authors: van de Sande, Jesse, Croom, Scott M., Bland-Hawthorn, Joss, Cortese, Luca, Scott, Nicholas, Lagos, Claudia D. P., D'Eugenio, Francesco, Bryant, Julia J., Brough, Sarah, Catinella, Barbara, Foster, Caroline, Groves, Brent, Harborne, Katherine E., López-Sánchez, Ángel R., McDermid, Richard, Medling, Anne, Owers, Matt S., Richards, Samuel N., Sweet, Sarah M., Vaughan, Sam P.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2021
• Subjects: cosmology: observations; galaxies: evolution; galaxies: formation; galaxies: kinematics and dynamics; galaxies: stellar content; galaxies: structure; sami
• Online Access: https://researchers.mq.edu.au/en/publications/002af51d-3d3b-42f6-b396-e594f34f9108; https://doi.org/10.1093/mnras/stab2647; https://research-management.mq.edu.au/ws/files/180023362/180018724.pdf; http://www.scopus.com/inward/record.url?scp=85119042543&partnerID=8YFLogxK; http://purl.org/au-research/grants/arc/FL150100019; http://purl.org/au-research/grants/arc/FT140100255

The kinematic morphology-density relation of galaxies is normally attributed to a changing distribution of galaxy stellar masses with the local environment. However, earlier studies were largely focused on slow rotators; the dynamical properties of the overall population in relation to environment have received less attention. We use the SAMI Galaxy Survey to investigate the dynamical properties of ∼1800 early and late-type galaxies with log (M ★ /M ⊙ ) > 9.5 as a function of mean environmental overdensity (Σ 5 ) and their rank within a group or cluster. By classifying galaxies into fast and slow rotators, at fixed stellar mass above log (M ★ /M ⊙ ) > 10.5, we detect a higher fraction (∼3.4σ) of slow rotators for group and cluster centrals and satellites as compared to isolated-central galaxies. We find similar results when using Σ 5 as a tracer for environment. Focusing on the fast-rotator population, we also detect a significant correlation between galaxy kinematics and their stellar mass as well as the environment they are in. Specifically, by using inclination-corrected or intrinsic λ Re values, we find that, at fixed mass, satellite galaxies on average have the lowest λ Re,intr , isolated-central galaxies have the highest λ Re,intr , and group and cluster centrals lie in between. Similarly, galaxies in high-density environments have lower mean λ Re,intr values as compared to galaxies at low environmental density. However, at fixed Σ 5 , the mean λ Re,intr differences for low and high-mass galaxies are of similar magnitude as when varying Σ 5 (Δ λ Re,intr ∼ 0.05, with σ random = 0.025, and σ syst < 0.03). Our results demonstrate that after stellar mass, environment plays a significant role in the creation of slow rotators, while for fast rotators we also detect an independent, albeit smaller, impact of mass and environment on their kinematic properties.