2022A&A...666L...5G


Query : 2022A&A...666L...5G

2022A&A...666L...5G - Astronomy and Astrophysics, volume 666, L5 (2022/10-1)

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

GARCIA-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., HONIG S., GARCIA-BURILLO S., ROSARIO D.J., WARD M.J., BELLOCCHI E., HICKS E.K.S., FULLER L. and PACKHAM C.

Abstract (from CDS):

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 (∼0.45″ 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.

Abstract Copyright: © I. García-Bernete et al. 2022

Journal keyword(s): galaxies: active - infrared: galaxies - galaxies: Seyfert - galaxies: ISM - ISM: molecules

Simbad objects: 6

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Number of rows : 6
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 BD+60 1753 * 17 24 52.2753625128 +60 25 50.749843296   9.72 9.65     A1V 32 0
2 NGC 6552 Sy2 18 00 07.2518347776 +66 36 54.360343188   14.6 13.74     ~ 162 2
3 * mu. Cep s*r 21 43 30.4595558543 +58 46 48.165937434 8.85 6.43 4.08 1.98 0.22 M2-Ia 669 1
4 NGC 7319 Sy2 22 36 03.602 +33 58 33.18   14.57 13.53 12.65   ~ 293 0
5 SN 2000ft SN* 23 03 15.45 +08 52 26.5           SNII 39 1
6 NGC 7469 Sy1 23 03 15.6 +08 52 26 12.60 13.00 12.34     ~ 2101 3

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