Science Highlights: Rotating Galaxies with ALMA and JWST

The image above shows ALMA CO gas-line data of three galaxies at z=0.5-2 (top row) from the ALPAKA study (Rizzo et al. 2023). The CO line emission revealed that these are regular rotating disk galaxies. JWST imaging (Roman-Oliveira et al. 2026) shows extended and symmetric stellar disks with spiral arms. Deeper analysis of the ALMA rotation patterns shows that rotation in the outer disk is well matched by expectations from stellar light. In the inner disk this is no longer true, with higher rotation speeds than expected. This suggests models fail to capture essential aspects about the bulge, dust attenuation, overmassive black holes, or dark-matter profiles as compared to local galaxies.