Dissecting disks and bulges with SAMI and Romulus

Dan Taranu (University of Western Australia)

June 27, 2016

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Abstract: Most stars in nearby galaxies are either part of dispersion-supported ellipsoids (bulges) or rotation-supported disks. While bulges are dominant at high masses and disks at low mass, most massive galaxies are composite systems embedded in a dark matter halo. Because of this, reducing galaxies to single measurements of fundamental physical quantities like size, mass, energy and spin is a significant challenge. I will introduce a novel method to simultaneously fit multi- wavelength photometry, resolved stellar kinematics from integral field spectroscopy and 21cm HI spectra with equilibrium 3D bulge/disk/halo models. Using data from the SAMI galaxy survey, we will provide robust structural decompositions for thousands of galaxies across broad ranges in stellar mass and morphology. I will also show predictions from the new Romulus cosmological simulation, a well-resolved 25 Mpc-cubed volume with innovative black hole accretion and feedback prescriptions. Together, these projects will strongly constrain local galaxy scaling relations and (when combined with z~1 observations) the physics of galaxy formation and evolution.