MICONIC: JWST/MIRI-MRS reveals heavily reprocessed PAH emission in the circum-nuclear disc of Centaurus A
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| Format: | Preprint |
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2026
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| author | Pantoni, L. Baes, M. Decin, L. Guillard, P. Herrero, A. Alonso Evangelista, L. Muñoz, L. Hermosa García-Bernete, I. Donnan, F. Buiten, V. Garcia-Burillo, S. Wright, G. Colina, L. Böker, T. Östlin, G. Dicken, D. Labiano, A. Rouan, D. van der Werf, P. Eckart, A. García-Marín, M. Güdel, M. Henning, Th. Lagage, P. -O. Walter, F. Ward, M. J. |
| author_facet | Pantoni, L. Baes, M. Decin, L. Guillard, P. Herrero, A. Alonso Evangelista, L. Muñoz, L. Hermosa García-Bernete, I. Donnan, F. Buiten, V. Garcia-Burillo, S. Wright, G. Colina, L. Böker, T. Östlin, G. Dicken, D. Labiano, A. Rouan, D. van der Werf, P. Eckart, A. García-Marín, M. Güdel, M. Henning, Th. Lagage, P. -O. Walter, F. Ward, M. J. |
| contents | Polycyclic aromatic hydrocarbons (PAHs) are key dust components in galaxies and play a fundamental role in the physics of the interstellar medium (ISM), yet their response to AGN feedback remains debated. We present a spatially resolved analysis of PAHs in the central $7^{\prime\prime}\times12^{\prime\prime}$ ($\sim100\times200$ pc$^2$) of Centaurus A. We use JWST/MIRI-MRS observations at 5-28 $μ$m from the MIRI European consortium GTO program MICONIC, with angular resolution of $0.35^{\prime\prime}-1^{\prime\prime}$ (about 6-17 pc). We derive PAH moment-0 maps via local continuum subtraction and extract one-dimensional spectra from five regions of interest, including the nucleus, the circumnuclear disc, and a PAH-deficient region. The spectra are decomposed into continuum, emission lines, and PAHs to measure feature intensities and equivalent widths (EWs). PAH emission is primarily distributed in a ring-like structure with localized enhancements at $\sim40$ pc from the nucleus. A distinct PAH-deficient region is observed to the north-west, roughly perpendicular to the jet axis, and coincident with enhanced ionized-gas velocity dispersion and inflowing molecular streamers. The 11.3/7.7 $μ$m and 6.2/7.7 $μ$m ratios exceed model predictions for pericondensed PAHs, indicating processed populations with more open structures. The 11.3/12.7 $μ$m ratio suggests a dominance of solo hydrogen sites and partial dehydrogenation, particularly in the PAH-deficient region, where shocks likely drive erosion. The largest EWs are found in the ring, while reduced values in the deficient region point to partial destruction; in the nucleus, low EWs are mainly due to continuum dilution. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2603_23674 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | MICONIC: JWST/MIRI-MRS reveals heavily reprocessed PAH emission in the circum-nuclear disc of Centaurus A Pantoni, L. Baes, M. Decin, L. Guillard, P. Herrero, A. Alonso Evangelista, L. Muñoz, L. Hermosa García-Bernete, I. Donnan, F. Buiten, V. Garcia-Burillo, S. Wright, G. Colina, L. Böker, T. Östlin, G. Dicken, D. Labiano, A. Rouan, D. van der Werf, P. Eckart, A. García-Marín, M. Güdel, M. Henning, Th. Lagage, P. -O. Walter, F. Ward, M. J. Astrophysics of Galaxies Polycyclic aromatic hydrocarbons (PAHs) are key dust components in galaxies and play a fundamental role in the physics of the interstellar medium (ISM), yet their response to AGN feedback remains debated. We present a spatially resolved analysis of PAHs in the central $7^{\prime\prime}\times12^{\prime\prime}$ ($\sim100\times200$ pc$^2$) of Centaurus A. We use JWST/MIRI-MRS observations at 5-28 $μ$m from the MIRI European consortium GTO program MICONIC, with angular resolution of $0.35^{\prime\prime}-1^{\prime\prime}$ (about 6-17 pc). We derive PAH moment-0 maps via local continuum subtraction and extract one-dimensional spectra from five regions of interest, including the nucleus, the circumnuclear disc, and a PAH-deficient region. The spectra are decomposed into continuum, emission lines, and PAHs to measure feature intensities and equivalent widths (EWs). PAH emission is primarily distributed in a ring-like structure with localized enhancements at $\sim40$ pc from the nucleus. A distinct PAH-deficient region is observed to the north-west, roughly perpendicular to the jet axis, and coincident with enhanced ionized-gas velocity dispersion and inflowing molecular streamers. The 11.3/7.7 $μ$m and 6.2/7.7 $μ$m ratios exceed model predictions for pericondensed PAHs, indicating processed populations with more open structures. The 11.3/12.7 $μ$m ratio suggests a dominance of solo hydrogen sites and partial dehydrogenation, particularly in the PAH-deficient region, where shocks likely drive erosion. The largest EWs are found in the ring, while reduced values in the deficient region point to partial destruction; in the nucleus, low EWs are mainly due to continuum dilution. |
| title | MICONIC: JWST/MIRI-MRS reveals heavily reprocessed PAH emission in the circum-nuclear disc of Centaurus A |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2603.23674 |