van de Sande, JVaughan, Sam PCortese, LucaScott, NicholasBland-Hawthorn, JossCroom, Scott Mdel P. Lagos, ClaudiaBrough, SarahBryant, Julia JDevriendt, Julien E GOh, Sree2024-03-182024-03-180035-8711http://hdl.handle.net/1885/316046Large galaxy samples from multiobject integral field spectroscopic (IFS) surveys now allow for a statistical analysis of the z similar to 0 galaxy population using resolved kinematic measurements. However, the improvement in number statistics comes at a cost, with multiobject IFS survey more severely impacted by the effect of seeing and lower signal-to-noise ratio. We present an analysis of similar to 1800 galaxies from the SAMI Galaxy Survey taking into account these effects. We investigate the spread and overlap in the kinematic distributions of the spin parameter proxy as a function of stellar mass and ellipticity epsilon(e). For SAMI data, the distributions of galaxies identified as regular and non-regular rotators with kinemetry show considerable overlap in the -epsilon(e) diagram. In contrast, visually classified galaxies (obvious and non-obvious rotators) are better separated in space, with less overlap of both distributions. Then, we use a Bayesian mixture model to analyse the observed -log(M-star/M-circle dot) distribution. By allowing the mixture probability to vary as a function of mass, we investigate whether the data are best fit with a single kinematic distribution or with two. Below log(M-star/M-circle dot) similar to 10.5, a single beta distribution is sufficient to fit the complete distribution, whereas a second beta distribution is required above log(M-star/M-circle dot) similar to 10.5 to account for a population of low- galaxies. While the Bayesian mixture model presents the cleanest separation of the two kinematic populations, we find the unique information provided by visual classification of galaxy kinematic maps should not be disregarded in future studies. Applied to mock-observations from different cosmological simulations, the mixture model also predicts bimodal distributions, albeit with different positions of the peaks. Our analysis validates the conclusions from previous, smaller IFS surveys, but also demonstrates the importance of using selection criteria for identifying different kinematic classes that are dictated by the quality and resolution of the observed or simulated data.The SAMI Galaxy Survey is based on observations made at the Anglo-Australian Telescope. The Sydney-AAO Multi-object Integral field spectrograph (SAMI) was developed jointly by the University of Sydney and the Australian Astronomical Observatory, and funded by ARC grants FF0776384 (Bland-Hawthorn) and LE130100198. The SAMI input catalogue is based on data taken from the Sloan Digital Sky Survey, the GAMA Survey, and the VST ATLAS Survey. The SAMI Galaxy Survey is supported by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013, the Australian Research Council Centre of Excellence for All-sky Astrophysics (CAASTRO), through project number CE110001020, and other participating institutions. JvdS acknowledges support of an Australian Research Council Discovery Early Career Research Award (project number DE200100461) funded by the Australian Government. LC is the recipient of an Australian Research Council Future Fellowship (FT180100066) funded by the Australian Government. NS acknowledges support of an Australian Research Council Discovery Early Career Research Award (project number DE190100375) funded by the Australian Government and a University of Sydney Postdoctoral Research Fellowship. The research of JD is supported by the Beecroft Trust and STFC. JBH is supported by an 0:funding-s ource 3:href="http://dx.doi.org/10.13039/501100001031" ARC /0: funding-source Laureate Fellowship (FL140100278) that funded the SAMI prototype. JJB acknowledges support of an Australian Research Council Future Fellowship (FT180100231). MSO acknowledges the funding support from the Australian Research Council through a Future Fellowship (FT140100255). FDE acknowledges funding through the H2020 ERC Consolidator Grant 683184. Parts of this research were conducted by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013.application/pdfen-AU© 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society202110.1093/mnras/stab14902022-11-13