Year: 2025
Type: article
Abstract: We present an analysis of the molecular specific angular momentum–mass (jH2 − MH2) relation using a sample of 51 nearby disc galaxies from the PHANGS-ALMA survey with deep high-resolution molecular gas rotation curves and surface density profiles. For the very first time, using a statistical sample, we report the discovery of a well-defined jH2 − MH2 relation. We quantify the scaling law by fitting a power law with a Bayesian framework, finding jH2 ∝ MH20.53. This slope closely resembles the well-known stellar j*–M* (Fall) relation, highlighting the dynamical connection between molecular gas and stars. We show that the jH2 − MH2 relation cannot be fully explained by analytic models of disc stability, but instead is well recovered with more complex physics as implemented in the SHARK semi-analytical model. These findings demonstrate the power of our novel jH2 − MH2 relation in testing galaxy evolution theories and in setting new constraints for models and simulations that reproduce a realistic interstellar medium. Additionally, our findings provide a critical benchmark for upcoming high-redshift studies of molecular gas kinematics, offering a local baseline to study the evolution of cold gas dynamics across cosmic time.
Source: Astronomy and Astrophysics
Institutions: Leiden University, Leiden Observatory
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
OpenAlex ID: W4408780924