Saved in:
| Main Authors: | , , , , , , , , , , , , , , , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2025
|
| Subjects: | |
| Online Access: | https://arxiv.org/abs/2512.04060 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866918230460727296 |
|---|---|
| author | Tarantino, Elizabeth J. Roman-Duval, Julia Sandstrom, Karin M. Smith, J. -D. T. Whitcomb, Cory M. Draine, Bruce T. Boyer, Martha L. Chastenet, Jérémy Chown, Ryan Clark, Christopher J. R. Gordon, Karl D. Hensley, Brandon S. Lai, Thomas S. -Y. Lindberg, Christina W. McQuinn, Kristen B. W. Newman, Max J. B. Telford, O. Grace Van De Putte, Dries Williams, Benjamin F. |
| author_facet | Tarantino, Elizabeth J. Roman-Duval, Julia Sandstrom, Karin M. Smith, J. -D. T. Whitcomb, Cory M. Draine, Bruce T. Boyer, Martha L. Chastenet, Jérémy Chown, Ryan Clark, Christopher J. R. Gordon, Karl D. Hensley, Brandon S. Lai, Thomas S. -Y. Lindberg, Christina W. McQuinn, Kristen B. W. Newman, Max J. B. Telford, O. Grace Van De Putte, Dries Williams, Benjamin F. |
| contents | The mid-infrared spectrum of star-forming, high metallicity galaxies is dominated by emission features from aromatic and aliphatic bonds in small carbonaceous dust grains, often referred to as polycyclic aromatic hydrocarbons (PAHs). In metal-poor galaxies, the abundance of PAHs relative to the total dust sharply declines, but the origin of this deficit is unknown. We present JWST observations that detect and resolve emission from PAHs in the 7% Solar metallicity galaxy Sextans A, representing the lowest metallicity detection of PAH emission to date. In contrast to higher metallicity galaxies, the clumps of PAH emission are compact (0.5-1.5'' or 3-10 pc), which explains why PAH emission evaded detection by lower resolution instruments like Spitzer. Ratios between the 3.3, 7.7, and 11.3 $μ$m PAH features indicate that the PAH grains in Sextans A are small and neutral, with no evidence of significant processing from the hard radiation fields within the galaxy. These results favor inhibited grain growth over enhanced destruction as the origin of the low PAH abundance in Sextans A. The compact clumps of PAH emission are likely active sites of in-situ PAH growth within a dense, well-shielded phase of the interstellar medium. Our results show that PAHs can form and survive in extremely metal-poor environments common early in the evolution of the Universe. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_04060 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | JWST Captures Growth of Aromatic Hydrocarbon Dust Particles in the Extremely Metal-poor Galaxy Sextans A Tarantino, Elizabeth J. Roman-Duval, Julia Sandstrom, Karin M. Smith, J. -D. T. Whitcomb, Cory M. Draine, Bruce T. Boyer, Martha L. Chastenet, Jérémy Chown, Ryan Clark, Christopher J. R. Gordon, Karl D. Hensley, Brandon S. Lai, Thomas S. -Y. Lindberg, Christina W. McQuinn, Kristen B. W. Newman, Max J. B. Telford, O. Grace Van De Putte, Dries Williams, Benjamin F. Astrophysics of Galaxies The mid-infrared spectrum of star-forming, high metallicity galaxies is dominated by emission features from aromatic and aliphatic bonds in small carbonaceous dust grains, often referred to as polycyclic aromatic hydrocarbons (PAHs). In metal-poor galaxies, the abundance of PAHs relative to the total dust sharply declines, but the origin of this deficit is unknown. We present JWST observations that detect and resolve emission from PAHs in the 7% Solar metallicity galaxy Sextans A, representing the lowest metallicity detection of PAH emission to date. In contrast to higher metallicity galaxies, the clumps of PAH emission are compact (0.5-1.5'' or 3-10 pc), which explains why PAH emission evaded detection by lower resolution instruments like Spitzer. Ratios between the 3.3, 7.7, and 11.3 $μ$m PAH features indicate that the PAH grains in Sextans A are small and neutral, with no evidence of significant processing from the hard radiation fields within the galaxy. These results favor inhibited grain growth over enhanced destruction as the origin of the low PAH abundance in Sextans A. The compact clumps of PAH emission are likely active sites of in-situ PAH growth within a dense, well-shielded phase of the interstellar medium. Our results show that PAHs can form and survive in extremely metal-poor environments common early in the evolution of the Universe. |
| title | JWST Captures Growth of Aromatic Hydrocarbon Dust Particles in the Extremely Metal-poor Galaxy Sextans A |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2512.04060 |