The SAMI galaxy survey:gas velocity dispersions in low-z star-forming galaxies and the drivers of turbulence

• Published in: Monthly Notices of the Royal Astronomical Society
• Main Authors: Varidel, Mathew R., Croom, Scott M., Lewis, Geraint F., Fisher, Deanne B., Glazebrook, Karl, Catinella, Barbara, Cortese, Luca, Krumholz, Mark R., Bland-Hawthorn, Joss, Bryant, Julia J., Groves, Brent, Brough, Sarah, Federrath, Christoph, Lawrence, Jon S., Lorente, Nuria P., Owers, Matt S., Richards, Samuel N., López-Sánchez, Ángel R., Sweet, Sarah M., van de Sande, Jesse, Vaughan, Sam P.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2020
• Subjects: Galaxies: disc; Methods: data analysis; Methods: statistical; Techniques: imaging spectroscopy; sami
• Online Access: https://researchers.mq.edu.au/en/publications/ce087aa9-d965-4ae7-9aec-3189a0dad289; https://doi.org/10.1093/MNRAS/STAA1272; https://research-management.mq.edu.au/ws/files/161807398/161804817.pdf; http://www.scopus.com/inward/record.url?scp=85091878320&partnerID=8YFLogxK; http://purl.org/au-research/grants/arc/FT140100255

We infer the intrinsic ionized gas kinematics for 383 star-forming galaxies across a range of integrated star formation rates (SFR ∈ [10 −3 , 10 2 ] M ⊙ yr −1 ) at z ≲ 0.1 using a consistent 3D forward-modelling technique. The total sample is a combination of galaxies from the Sydney-AAO Multiobject Integral field Spectrograph (SAMI) Galaxy survey and DYnamics of Newly Assembled Massive Objects survey. For typical low-z galaxies taken from the SAMI Galaxy Survey, we find the vertical velocity dispersion (σ v ,z ) to be positively correlated with measures of SFR, stellar mass, H I gas mass, and rotational velocity. The greatest correlation is with SFR surface density (∑ SFR ). Using the total sample, we find σ v ,z increases slowly as a function of integrated SFR in the range SFR ∈ [10 −3 , 1] M ⊙ yr −1 from 17 ± 3 to 24 ± 5 km s −1 followed by a steeper increase up to σ v ,z ∼80 km s −1 for SFR 1M ⊙ yr −1 . This is consistent with recent theoretical models that suggest a σ v ,z floor driven by star formation feedback processes with an upturn in σ v ,z at higher SFR driven by gravitational transport of gas through the disc.