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Polycyclic aromatic hydrocarbon destruction in star-forming regions across 42 nearby galaxies

Polycyclic aromatic hydrocarbons (PAHs) are widespread in the interstellar medium (ISM) of near solar metallicity galaxies, where they play a critical role in ISM heating, cooling, and reprocessing stellar radiation. The PAH fraction, the abundance of PAHs relative to total dust mass, is a key param...

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Main Authors: Egorov, Oleg (Author) , Leroy, Adam K. (Author) , Sandstrom, Karin (Author) , Kreckel, Kathryn (Author) , Baron, Dalya (Author) , Belfiore, Francesco (Author) , Chown, Ryan (Author) , Sutter, Jessica (Author) , Boquien, Médéric (Author) , Saguer, Mar Canal i (Author) , Congiu, Enrico (Author) , Dale, Daniel A. (Author) , Egorova, Evgeniya (Author) , Huber, Michael (Author) , Li, Jing (Author) , Williams, Thomas G. (Author) , Chastenet, Jérémy (Author) , Chiang, I.-Da (Author) , Gerasimov, Ivan (Author) , Hassani, Hamid (Author) , Kim, Hwihyun (Author) , Koziol, Hannah (Author) , Lee, Janice C. (Author) , McClain, Rebecca L. (Author) , Delgado, José Eduardo Méndez (Author) , Pan, Hsi-An (Author) , Pathak, Debosmita (Author) , Rosolowsky, Erik (Author) , Sarbadhicary, Sumit K. (Author) , Schinnerer, Eva (Author) , Thilker, David (Author) , Ubeda, Leonardo (Author) , Weinbeck, Tony (Author)
Format: Article (Journal)
Language:English
Published: November 2025
In: Astronomy and astrophysics
Year: 2025, Volume: 703, Pages: 1-19
ISSN:1432-0746
DOI:10.1051/0004-6361/202556427
Online Access:Verlag, kostenfrei, Volltext: https://doi.org/10.1051/0004-6361/202556427
Verlag, kostenfrei, Volltext: https://www.aanda.org/articles/aa/abs/2025/11/aa56427-25/aa56427-25.html
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Author Notes:Oleg V. Egorov, Adam K. Leroy, Karin Sandstrom, Kathryn Kreckel, Dalya Baron, Francesco Belfiore, Ryan Chown, Jessica Sutter, Médéric Boquien, Mar Canal i Saguer, Enrico Congiu, Daniel A. Dale, Evgeniya Egorova, Michael Huber, Jing Li, Thomas G. Williams, Jérémy Chastenet, I.-Da Chiang, Ivan Gerasimov, Hamid Hassani, Hwihyun Kim, Hannah Koziol, Janice C. Lee, Rebecca L. McClain, José Eduardo Méndez Delgado, Hsi-An Pan, Debosmita Pathak, Erik Rosolowsky, Sumit K. Sarbadhicary, Eva Schinnerer, David Thilker, Leonardo Ubeda, and Tony Weinbeck
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Summary:Polycyclic aromatic hydrocarbons (PAHs) are widespread in the interstellar medium (ISM) of near solar metallicity galaxies, where they play a critical role in ISM heating, cooling, and reprocessing stellar radiation. The PAH fraction, the abundance of PAHs relative to total dust mass, is a key parameter in ISM physics. Using JWST and MUSE observations of 42 galaxies from the PHANGS survey, we analyzed the PAH fraction in over 17 000 H II regions spanning a gas-phase oxygen abundance of 12 + log(O/H) = 8.0-8.8 (Z ∼ 0.2-1.3 Z⊙), and ∼400 isolated supernova remnants (SNRs). We find a significantly lower PAH fraction toward H II regions compared to a reference sample of diffuse ISM areas at matched metallicity. At 12 + log(O/H) > 8.2, the PAH fraction toward H II regions is strongly anti-correlated with the local ionization parameter, suggesting that PAH destruction is correlated with ionized gas and/or hydrogen-ionizing UV radiation. At lower metallicities, the PAH fraction declines steeply in H II regions and in the diffuse ISM, likely reflecting less efficient PAH formation in metal-poor environments. Carefully isolating dust emission from the vicinity of optically identified supernova remnants, we see evidence of selective PAH destruction from measurements of lower PAH fractions, which is, however, indistinguishable at ∼50 pc scales. Overall, our results point to ionizing radiation as the dominant agent of PAH destruction within H II regions; metallicity plays a key role in their global abundance in galaxies.
Item Description:Online veröffentlicht: 18. November 2025
Gesehen am 04.03.2026
Physical Description:Online Resource
ISSN:1432-0746
DOI:10.1051/0004-6361/202556427

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