The SAMI Galaxy Survey: the link between angular momentum and optical morphology

Abstract

We investigate the relationship between stellar and gas specific angular momentum j, stellar mass M * and optical morphology for a sample of 488 galaxies extracted from the SAMI Galaxy Survey. We find that j, measured within one effective radius, monotonically increases with M * and that, for M * >10 9.5 M , the scatter in this relation strongly correlates with optical morphology (i.e., visual classification and Sérsic index). These findings confirm that massive galaxies of all types lie on a plane relating mass, angular momentum and stellar light distribution, and suggest that the largescale morphology of a galaxy is regulated by its mass and dynamical state. We show that the significant scatter in the M * − j relation is accounted for by the fact that, at fixed stellar mass, the contribution of ordered motions to the dynamical support of galaxies varies by at least a factor of three. Indeed, the stellar spin parameter (quantified via λ R ) correlates strongly with Sérsic and concentration indices. This correlation is particularly strong once slow-rotators are removed from the sample, showing that late-type galaxies and early-type fast rotators form a continuous class of objects in terms of their kinematic properties.

Angular momentum-related probe of cold gas deficiencies

“…To estimate j * , they used star particles only, while the estimation of j gas made use of all gas particles that have a neutral gas fraction > 0. Lagos et al showed that the stellar M *j * relation in EAGLE galaxies of different morphologies has good agreement with measurements in the local universe by Romanowsky & Fall (2012); Obreschkow & Glazebrook (2014); Cortese et al (2016). The resolution limit of the simulation constrains the galaxy selection.…”

From peculiar morphologies to Hubble-type spirals: the relation between galaxy dynamics and morphology in star-forming galaxies at z ∼ 1.5

“…We show the relation between ∆j and Sérsic index for z ∼ 0 galaxies from Romanowsky & Fall (2012). The parameterisation of the relation is taken from Cortese et al (2016) who established the j * -M *n relation for the SAMI survey. We note the parameterisation derived in Cortese et al (2016) is for a morphologically diverse population of both quiescent and star-forming low redshift galaxies, and therefore should not be compared directly to our sample of star-forming selected high-redshift galaxies.…”

“…More recent integral field studies of low redshift galaxies have analysed the connection between a galaxy's parameterised morphology (e.g. Sérsic index, stellar bulge to total ratio) and specific angular momentum (Obreschkow & Glazebrook 2014;Cortese et al 2016). More bulge dominated galaxies, with higher Sérsic indices, have been shown to have lower specific angular momentum at fixed stellar mass (Fall & Romanowsky 2018).…”

The SAMI Galaxy Survey: Data Release One with emission-line physics value-added products

“…A galaxy's accretion and merger history is central to defining its character, and aspects of this history are encoded in the lineof-sight velocity distributions. By studying the detailed kinematics of galaxies across the mass and environment plane, we unlock a new view of galaxy evolution (Cortese et al 2016;van de Sande et al 2017). IFS has defined a new set of morphological classifications in terms of dynamical properties (e.g.…”