Rotation curves showing the circular velocity for stars (red), gas (blue) and dark matter (black) as dashed lines and rotation velocities (solid lines) of young stars (age  < 100 Myr at z = 0) and gas as a function of radius. Two blue diamonds denote the inner and outer “disk radii” at an arbitrary vertical position. These values are chosen from inspection of the rotation curve of the gas, surface density maps, stellar surface density profiles and metallicity profiles. The most conservative choice is made to avoid spurious fits but to maintain consistency throughout the analysis.