3D-Barolo: a new 3D algorithm to derive rotation curves of galaxies

TL;DR

3D-Barolo is a new software that accurately derives galaxy rotation curves from spectroscopic data by fitting 3D models, outperforming traditional 2D methods, and is suitable for large datasets and various observational instruments.

Contribution

The paper introduces 3D-Barolo, a novel 3D algorithm that improves rotation curve derivation from spectroscopic data, especially for barely resolved galaxies, and supports automated analysis of large datasets.

Findings

Performs better than 2D methods on velocity fields.

Recovers true rotation curves even in barely resolved galaxies.

Suitable for diverse instruments and large datasets.

Abstract

We present 3D-Barolo, 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 HI 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. 3D-Barolo can recover the true rotation curve and estimate the intrinsic velocity dispersion even in barely resolved galaxies (about 2 resolution elements) provided that the signal to noise of the data is larger that 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 datasets. These features make 3D-Barolo 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 IFUs, ALMA and the SKA pathfinders.