3D BAROLO: A new 3D algorithm to derive rotation curves of galaxies

We present 3DBAROLO,† a new code that derives rotation curves of galaxies from emission-line observations. This software fits 3D tilted-ring models to spectroscopic data cubes and can be used with a variety of observations: from H I and molecular lines to optical/IR recombination lines. We describe the structure of the main algorithm and show that it performs much better than the standard 2D approach on velocity fields. A number of successful applications, from high to very low spatial resolution data are presented and discussed. 3DBAROLO can recover the true rotation curve and estimate the intrinsic velocity dispersion even in barely resolved galaxies (~2 resolution elements) provided that the signal to noise of the data is larger than 2-3. It can also be run automatically thanks to its source-detection and first-estimate modules, which make it suitable for the analysis of large 3D data sets. These features make 3DBAROLO a uniquely useful tool to derive reliable kinematics for both local and high-redshift galaxies from a variety of different instruments including the new generation Integral Field Units, ALMA and the SKA pathfinders.