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

• Main Authors: Cortese, L., Fogarty, L. M. R., Bekki, K., van de Sande, J., Couch, W., Catinella, B., Colless, M., Obreschkow, D., Taranu, D., Tescari, E., Barat, D., Bland-Hawthorn, J., Bloom, J., Bryant, J. J., Cluver, M., Croom, S. M., Drinkwater, M. J., d'Eugenio, F., Konstantopoulos, I. S., Lopez-Sanchez, A., Mahajan, S., Scott, N., Tonini, C., Wong, O. I., Allen, J. T., Brough, S., Goodwin, M., Green, A. W., Ho, I. -T., Kelvin, L. S., Lawrence, J. S., Lorente, N. P. F., Medling, A. M., Owers, M. S., Richards, S., Sharp, R., Sweet, S. M.
• Format: Text
• Language: unknown
• Published: arXiv 2016
• Subjects: Astrophysics of Galaxies astro-ph.GA; FOS Physical sciences; sami
• Online Access: https://dx.doi.org/10.48550/arxiv.1608.00291; https://arxiv.org/abs/1608.00291

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$_{\odot}$, 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 large-scale 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. : 16 pages, 8 figures, 1 table. Accepted for publication in MNRAS