James Webb Space Telescope Feed Post

Arxiv: JWST Observations of Starbursts: Relations between PAH features and CO clouds in the starburst galaxy M 82 Published: 1/24/2025 9:33:31 PM Updated: 1/28/2025 1:16:40 PM

Paper abstract: We present a study of new 7.7-11.3 \mum data obtained with the James WebbSpace Telescope Mid-InfraRed Instrument in the starburst galaxy M 82. Inparticular, we focus on the dependency of the integrated CO(1-0) line intensityon the MIRI-F770W and MIRI-F1130W filter intensities to investigate thecorrelation between CO content and the 7.7 and 11.3 \mum features frompolycyclic aromatic hydrocarbons (PAH) in M 82's outflows. To perform ouranalysis, we identify CO clouds using archival ^{12}CO(J=1-0) NOEMA moment0 map within 2 kpc from the center of M 82, with sizes ranging between ~21and 270 pc; then, we compute the CO-to-PAH relations for the 306 validated COclouds. On average, the power-law slopes for the two relations in M 82 arelower than what is seen in local main-sequence spirals. In addition, there is amoderate correlation between I_{\rm CO(1-0)}-I_{\rm 7.7\mu m} /I_{\rm11.3\mu m} for most of the CO cloud groups analyzed in this work. Our resultssuggest that the extreme conditions in M 82 translate into CO not tracing thefull budget of molecular gas in smaller clouds, perhaps as a consequence ofphotoionization and/or emission suppression of CO molecules due to hardradiation fields from the central starburst.