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

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...

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Bibliographic Details
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
Description
Summary: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.

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