THE SAMI GALAXY SURVEY: TOWARD A UNIFIED DYNAMICAL SCALING RELATION FOR GALAXIES OF ALL TYPES

• Published in: The Astrophysical Journal
• Main Authors: Cortese, L., Fogarty, L. M. R., Ho, I.-T., Bekki, K., Bland-Hawthorn, J., Colless, M., Couch, W., Croom, S. M., Glazebrook, K., Mould, J., Scott, N., Sharp, R., Tonini, C., Allen, J. T., Bloom, J., Bryant, J. J., Cluver, M., Davies, Roger L., Drinkwater, M. J., Goodwin, M., Green, A., Kewley, L. J., Kostantopoulos, I. S., Lawrence, J. S., Mahajan, S., Medling, A. M., Owers, M., Richards, S. N., Sweet, S. M., Wong, O. I.
• Other Authors: Swinburne University of Technology
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: American Astronomical Society 2014
• Subjects: sami
• Online Access: http://hdl.handle.net/1959.3/388853; https://doi.org/10.1088/2041-8205/795/2/L37

We take advantage of the first data from the Sydney-AAO Multi-object Integral field Galaxy Survey to investigate the relation between the kinematics of gas and stars, and stellar mass in a comprehensive sample of nearby galaxies. We find that all 235 objects in our sample, regardless of their morphology, lie on a tight relation linking stellar mass (M∗) to internal velocity quantified by the S0.5 parameter, which combines the contribution of both dispersion (σ) and rotational velocity (Vrot) to the dynamical support of a galaxy (S0.5 = √ 0.5 Vrot2 + σ2). Our results are independent of the baryonic component from which σ and V rot are estimated, as the S 0.5 of stars and gas agree remarkably well. This represents a significant improvement compared to the canonical M∗ versus Vrot and M∗ versus σ relations. Not only is no sample pruning necessary, but also stellar and gas kinematics can be used simultaneously, as the effect of asymmetric drift is taken into account once Vrot and σ are combined. Our findings illustrate how the combination of dispersion and rotational velocities for both gas and stars can provide us with a single dynamical scaling relation valid for galaxies of all morphologies across at least the stellar mass range 8.5