2025/09/26 by Savannah Gramze, Gramze, Savannah, Adam Ginsburg +30 · 1 voice · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Extinction (optical mineralogy) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Milky Way #Protein filament #Star formation #Stars #astro-ph.GA
paper · pdf · open access · doi:10.33232/001c.165431
published in The Open Journal of Astrophysics 9
openalex publication_date 2026/07/23 · openalex created_date 2026/07/24 · openalex updated_date 2026/08/05
CO gas emission is a fundamental tool for measuring column density, but in cold, dark clouds, much of the CO is locked away in ice. We present JWST results from observations of a star forming filament (G0.342+0.024) that that appears to be associated with the 3 kpc arm. This filament is backlit by the Galactic Center, which has allowed us to construct a high-resolution extinction map (mean separation between stars of ~1” outside the filament, ~2” in the filament). ALMA Band 3 data reveals embedded star formation within the cloud. Using the CO ice feature covered by the F466N band, we map the CO ice column density of the filament. By combining the extinction map, CO ice column density map, and archival CO observations, we examine the efficacy of standard CO X-factor measurements of mass in star forming gas. We find that 50-88% of the CO is locked away in ice at large column densities () in the filament. The primary sources of uncertainty in this estimate are due to uncertainty in the ice composition and lab measurements of ice opacities. This shows that systematic corrections are needed for mass measurements in the Milky Way and nearby galaxies at high column densities.