Unveiling the Secrets of Extragalactic Molecular Clouds: A JWST Adventure
The cosmos just got a little clearer, but also a lot more mysterious!
The James Webb Space Telescope (JWST) has gifted us with unprecedented views of nearby spiral galaxies, revealing intricate structures of polycyclic aromatic hydrocarbons (PAHs) that trace molecular gas, even in regions devoid of carbon monoxide (CO).
Our team, PHANGS-JWST, has identified an astonishing 108,466 to 146,040 interstellar medium (ISM) cloud structures in 66 galaxies, using PAH maps at two different resolutions. We've inferred molecular properties by converting PAH emissions to CO, a standard practice, but with an intriguing twist: the most massive clouds tend to reside in spiral arms, suggesting enhanced formation due to gravitational forces.
But here's where it gets controversial... While molecular surface densities generally decrease as we move away from the galaxy centers, the trend varies wildly between individual galaxies. Some show flat or even no decline, hinting at the influence of large-scale processes and unique morphologies.
And this is the part most people miss... We've published two comprehensive catalogs online, one at a common resolution of 30 pc and another at the native resolution, offering a treasure trove for future studies on PAH clouds, molecular clouds, and star formation. These catalogs are a game-changer, providing an unprecedented level of detail and utility.
So, what do you think? Are we on the right track with our interpretations, or is there something else at play here? Feel free to share your thoughts and insights in the comments below! We'd love to hear your opinions and engage in a thought-provoking discussion.
Authors: Z. Bazzi, D. Colombo, F. Bigiel, A. K. Leroy, E. Rosolowsky, K. Sandstrom, et al.
Comments: 24 pages, 18 figures, accepted for publication in A&A
Subjects: Astrophysics of Galaxies (astro-ph.GA)
For more details and the full paper, visit: https://doi.org/10.48550/arXiv.2511.06596
