JWST Observations of Starbursts: Polycyclic Aromatic Hydrocarbons Closely Trace the Cool Phase of M82’s Galactic Wind

Abstract Stellar feedback drives multiphase gas outflows from starburst galaxies, but the interpretation of dust emission in these winds remains uncertain. To investigate this, we analyze new JWST mid-infrared images tracing polycyclic aromatic hydrocarbon (PAH) emission at 7.7 and 11.3 μ m from the outflow of the prototypical starburst M82 out to 3.2 kpc. We find that PAH emission shows significant correlations with CO, H α , and X-ray emission within the outflow, though the strengths and behaviors of these correlations vary with gas phase and distance from the starburst. PAH emission correlates strongly with cold molecular gas, with PAH–CO scaling relations in the wind nearly identical to those in galaxy disks despite the very different conditions. The H α –PAH correlation indicates that H α traces the surfaces of PAH-bearing clouds, consistent with arising from ionized layers produced by shocks. Meanwhile, the PAH–X-ray correlation disappears once distance effects are controlled for past 2 kpc, suggesting that PAHs are decoupled from the hot gas and the global correlation merely reflects the large-scale structure of the outflow. The PAH-to-neutral gas ratio remains nearly flat to 2 kpc, with variations following changes in the radiation field. This implies that the product of PAH abundance and dust-to-gas ratio does not change significantly over the inner portion of the outflow. Together, these results demonstrate that PAHs robustly trace the cold phase of M82’s wind, surviving well beyond the starburst and providing a powerful, high-resolution proxy for mapping the life cycle of entrained cold material in galactic outflows.

Authors

Institutions

Publication Details

Journal
The Astrophysical Journal Letters
Published
2026-02-24
DOI
https://doi.org/10.3847/2041-8213/ae4508
Primary Topic
Gamma-ray bursts and supernovae
Type
article
Field-Weighted Citation Impact
0.00
Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

JWST Observations of Starbursts: Polycyclic Aromatic Hydrocarbons Closely Trace the Cool Phase of M82’s Galactic Wind

J. D. Smith, David S. Meier, Thomas S. -Y. Lai, Fabian Walter et al.
The Astrophysical Journal Letters
Gamma-ray bursts and supernovae
article

JWST Observations of Starbursts: Polycyclic Aromatic Hydrocarbons Closely Trace the Cool Phase of M82’s Galactic Wind

J. D. Smith, David S. Meier, Thomas S. -Y. Lai, Fabian Walter, Martha L. Boyer, K. L. Emig, Colton Ring, Ryan Chown, Rebecca C. Levy, Sylvain Veilleux, L. Armus, Vicente Villanueva, Rodrigo Herrera-Camus, Simon C. O. Glover, David B. Fisher, Laura Lenkić, J. Ott, Leindert Boogaard, Todd A. Thompson, Elisabeth A. C. Mills, Ralf S. Klessen, Alberto D. Bolatto, Elizabeth Tarantino, Sebastián López, Laura A. Lopez, Evan D. Skillman, P. van der Werf, Serena A. Cronin, Daniel A. Dale, Keaton Donaghue, Adam K. Leroy
article en

Abstract

Abstract Stellar feedback drives multiphase gas outflows from starburst galaxies, but the interpretation of dust emission in these winds remains uncertain. To investigate this, we analyze new JWST mid-infrared images tracing polycyclic aromatic hydrocarbon (PAH) emission at 7.7 and 11.3 μ m from the outflow of the prototypical starburst M82 out to 3.2 kpc. We find that PAH emission shows significant correlations with CO, H α , and X-ray emission within the outflow, though the strengths and behaviors of these correlations vary with gas phase and distance from the starburst. PAH emission correlates strongly with cold molecular gas, with PAH–CO scaling relations in the wind nearly identical to those in galaxy disks despite the very different conditions. The H α –PAH correlation indicates that H α traces the surfaces of PAH-bearing clouds, consistent with arising from ionized layers produced by shocks. Meanwhile, the PAH–X-ray correlation disappears once distance effects are controlled for past 2 kpc, suggesting that PAHs are decoupled from the hot gas and the global correlation merely reflects the large-scale structure of the outflow. The PAH-to-neutral gas ratio remains nearly flat to 2 kpc, with variations following changes in the radiation field. This implies that the product of PAH abundance and dust-to-gas ratio does not change significantly over the inner portion of the outflow. Together, these results demonstrate that PAHs robustly trace the cold phase of M82’s wind, surviving well beyond the starburst and providing a powerful, high-resolution proxy for mapping the life cycle of entrained cold material in galactic outflows.

The Astrophysical Journal LettersVol. 999(1)
Leiden University (NL), California Institute of Technology (US), University of Wyoming (US), Space Telescope Science Institute (US), University of Minnesota (US), University of Kansas (US), University of Concepción (CL), New Mexico Institute of Mining and Technology (US), Heidelberg University (DE), National Radio Astronomy Observatory (US), European Space Agency (FR), Millennium Science Initiative (CL), ASTRO-3D (AU), Max Planck Institute for Astronomy (DE), Joint Space Science Institute (US), ARC Centre of Excellence for All-sky Astrophysics (AU), Millenium Nucleus for Planet Formation (CL), Infrared Processing and Analysis Center (US), The Ohio State University (US), Swinburne University of Technology (AU), University of Maryland, College Park (US), Heidelberg Institute for Theoretical Studies (DE), University of Toledo (US)
Openalex Percentile: Top 100%
Gamma-ray bursts and supernovae
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.