The SAMI Galaxy Survey:the contribution of different kinematic classes to the stellar mass function of nearby galaxies

• Published in: Monthly Notices of the Royal Astronomical Society
• Main Authors: Guo, Kexin, Cortese, Luca, Obreschkow, Danail, Catinella, Barbara, van de Sande, Jesse, Croom, Scott M., Brough, Sarah, Sweet, Sarah, Bryant, Julia J., Medling, Anne, Bland-Hawthorn, Joss, Owers, Matt, Richards, Samuel N.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2020
• Subjects: Galaxies: abundances; Galaxies: kinematics and dynamics; Galaxies: stellar content; sami
• Online Access: https://researchers.mq.edu.au/en/publications/289ccca1-8b0b-43c3-94f1-5061e3d7b86b; https://doi.org/10.1093/mnras/stz3042; http://www.scopus.com/inward/record.url?scp=85079669162&partnerID=8YFLogxK; http://purl.org/au-research/grants/arc/CE170100013; http://purl.org/au-research/grants/arc/FT140100255

We use the complete Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey to determine the contribution of slow rotators (SRs), as well as different types of fast rotators (FRs), to the stellar mass function of galaxies in the local Universe. We use stellar kinematics not only to discriminate between fast and SRs, but also to distinguish between dynamically cold systems (i.e. consistent with intrinsic axis ratios <0.3) and systems including a prominent dispersion-supported bulge. We show that FRs account for more than 80 per cent of the stellar mass budget of nearby galaxies, confirming that their number density overwhelms that of SRs at almost all masses from 10 9 to 10 11.5 M ☉ . Most importantly, dynamically cold discs contribute to at least 25 per cent of the stellar mass budget of the local Universe, significantly higher than what is estimated from visual morphology alone. For stellar masses up to 10 10.5 M ☉ , this class makes up >= 30 per cent of the galaxy population in each stellar mass bin. The fact that many galaxies that are visually classified as having two-components have stellar spin consistent with dynamically cold discs suggests that the inner component is either rotationally dominated (e.g. bar, pseudo-bulge) or has little effect on the global stellar kinematics of galaxies.