Astrochemistry

JWST Observations of Starbursts: Relations Between PAH Features and CO Clouds in the Starburst Galaxy M 82

By Keith Cowing
Status Report
astro-ph.GA
January 29, 2025
Filed under , , , , , , ,
JWST Observations of Starbursts: Relations Between PAH Features and CO Clouds in the Starburst Galaxy M 82
From left to right: M 82 NOEMA CO(J=1-0), MIRI-F770W, and MIRI-F1130W images in cutouts of 5′ ×4.2 ′. The left panel also contains the molecular clouds identified in §3.2 (white contours), the centroid of the CO(J = 1 − 0) and the different regions identified in the starburst as described in Krieger et al. (2021). The inset in the left panel correspond to the NOEMA beamsize at ν = 115 GHz. The green crosses in the middle and right panels are indicate the optical center of M 82. The black contours in the middle and right panels correspond to the regions covered by the MIRI-MRS and the yellow boxes are the regions with Spitzer IRS data from Beirão et al. (2008); both are used in this work to apply a first-order continuum subtraction (see §3.1). — astro-ph.GA

We present a study of new 7.7-11.3 μm data obtained with the James Webb Space Telescope Mid-InfraRed Instrument in the starburst galaxy M 82.

In particular, we focus on the dependency of the integrated CO(1-0) line intensity on the MIRI-F770W and MIRI-F1130W filter intensities to investigate the correlation between CO content and the 7.7 and 11.3 μm features from polycyclic aromatic hydrocarbons (PAH) in M 82’s outflows.

To perform our analysis, we identify CO clouds using archival 12CO(J=1-0) NOEMA moment 0 map within 2 kpc from the center of M 82, with sizes ranging between ∼21 and 270 pc; then, we compute the CO-to-PAH relations for the 306 validated CO clouds. On average, the power-law slopes for the two relations in M 82 are lower than what is seen in local main-sequence spirals.

In addition, there is a moderate correlation between ICO(1−0)-I7.7μm/I11.3μm for most of the CO cloud groups analyzed in this this http URL results suggest that the extreme conditions in M 82 translate into CO not tracing the full budget of molecular gas in smaller clouds, perhaps as a consequence of photoionization and/or emission suppression of CO molecules due to hard radiation fields from the central starburst.

V. Villanueva, A. D. Bolatto, R. Herrera-Camus, A. Leroy, D. B. Fisher, R. C. Levy, T. Böker, L. Boogaard, S. A. Cronin, D. A. Dale, K. Emig, I. De Looze, G. P. Donnelly, T. S.-Y. Lai, L. Lenkic, S. Lopez, D. S. Meier, J. Ott, M. Relano, J. D. Smith, E. Tarantino, S. Veilleux, P. van der Werf

Subjects: Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2501.14893 [astro-ph.GA] (or arXiv:2501.14893v1 [astro-ph.GA] for this version)
https://doi.org/10.48550/arXiv.2501.14893
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Submission history
From: Vicente Villanueva
[v1] Fri, 24 Jan 2025 19:33:31 UTC (5,437 KB)
https://arxiv.org/abs/2501.14893
Astrobiology,

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻