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A high angular resolution view of the PAH emission in Seyfert galaxies using JWST/MRS data

García-Bernete, I.; Rigopoulou, D.; Alonso-Herrero, A.; Donnan, F.R.; Roche, P.F.; Pereira-Santaella, M.; Labiano, A.; Peralta de Arriba, L.; Izumi, T.; Ramos Almeida, C.; Shimizu, T.; Hönig, S.; García-Burillo, S.; Rosario, D.J.; Ward, M.J.; Bellocchi, E.; Hicks, E.K.S.; Fuller, L.; Packham, C.

A high angular resolution view of the PAH emission in Seyfert galaxies using JWST/MRS data Thumbnail


I. García-Bernete

D. Rigopoulou

A. Alonso-Herrero

F.R. Donnan

P.F. Roche

M. Pereira-Santaella

A. Labiano

L. Peralta de Arriba

T. Izumi

C. Ramos Almeida

T. Shimizu

S. Hönig

S. García-Burillo

D.J. Rosario

E. Bellocchi

E.K.S. Hicks

L. Fuller

C. Packham


Polycyclic aromatic hydrocarbons (PAHs) are carbon-based molecules that are ubiquitous in a variety of astrophysical objects and environments. In this work we use JWST/MIRI MRS spectroscopy of three Seyferts to compare their nuclear PAH emission with that of star-forming (SF) regions. This study represents the first of its kind to use sub-arcsecond angular resolution data of local luminous Seyferts (Lbol > 1044.46 erg s−1 ) with a wide wavelength coverage (4.9–28.1 µm). We present an analysis of their nuclear PAH properties by comparing the observed ratios with PAH diagnostic model grids derived from theoretical spectra. Our results show that a suite of PAH features is present in the innermost parts of luminous Seyfert galaxies (∼0.4500 at 12 µm; in the inner ∼142–245 pc). We find that the nuclear regions of active galactic nuclei (AGN) lie at different positions of the PAH diagnostic diagrams, whereas the SF regions are concentrated around the average values of SF galaxies. In particular, we find that the nuclear PAH emission mainly originates in neutral PAHs. In contrast, PAH emission originating in the SF regions favours ionised PAH grains. The observed PAH ratios in the nuclear region of the AGN-dominated galaxy NGC 6552 indicate the presence of larger PAH molecules compared with those of the SF regions. Therefore, our results provide evidence that the AGN have a significant impact on the ionisation state (and probably the size) of the PAH grains on scales of ∼142–245 pc.


García-Bernete, I., Rigopoulou, D., Alonso-Herrero, A., Donnan, F., Roche, P., Pereira-Santaella, M., …Packham, C. (2022). A high angular resolution view of the PAH emission in Seyfert galaxies using JWST/MRS data. Astronomy & Astrophysics, 666, Article L5.

Journal Article Type Article
Acceptance Date Sep 20, 2022
Online Publication Date Sep 30, 2022
Publication Date 2022
Deposit Date Mar 6, 2023
Publicly Available Date Mar 6, 2023
Journal Astronomy & Astrophysics
Print ISSN 0004-6361
Electronic ISSN 1432-0746
Publisher EDP Sciences
Peer Reviewed Peer Reviewed
Volume 666
Article Number L5


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Copyright Statement
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (,<br /> which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.<br /> This article is published in open access under the Subscribe-to-Open model. Subscribe to A&amp;A to support open access publication.

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