GOALS-JWST: Small Neutral Grains and Enhanced 3.3 μm PAH Emission in the Seyfert Galaxy NGC 7469

We present James Webb Space Telescope (JWST) Near Infrared Spectrograph (NIRSpec) integral field spectroscopy of the nearby luminous infrared galaxy NGC 7469. We take advantage of the high spatial/spectral resolution and wavelength coverage of JWST/NIRSpec to study the 3.3 μm neutral polycyclic arom...

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Detalles Bibliográficos
Autores: Lai, T.S., Armus, L., Bianchin, M., Díaz-Santos, T., Linden, S.T., Privon, G.C., Inami, H., Vivian, U., Bohn, T., Evans, A.S., Larson, K.L., Hensley, B.S., Smith, J.T., Malkan, M.A., Song, Y., Stierwalt, S., van der Werf, P.P., McKinney, J., Aalto, S., Buiten, V.A., Rich, J., Charmandaris, V., Appleton, P., Barcos-Muñoz, L., Böker, T., Finnerty, L., Kader, J.A., Law, D.R., Medling, A.M., Brown, M.J.I., Hayward, C.C., Howell, J., Iwasawa, Kazushi, Kemper, F., Marshall, J., Mazzarella, J.M., Müller-Sánchez, F., Murphy, E.J., Sanders, D., Surace, J.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2023
País:España
Institución:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repositorio:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:2445/218369
Acceso en línea:https://hdl.handle.net/2445/218369
Access Level:acceso abierto
Palabra clave:Nucli galàctic actiu
Hidrocarburs aromàtics policíclics
Galàxies
Active galactic nuclei
Polycyclic aromatic hydrocarbons
Galaxies
Descripción
Sumario:We present James Webb Space Telescope (JWST) Near Infrared Spectrograph (NIRSpec) integral field spectroscopy of the nearby luminous infrared galaxy NGC 7469. We take advantage of the high spatial/spectral resolution and wavelength coverage of JWST/NIRSpec to study the 3.3 μm neutral polycyclic aromatic hydrocarbon (PAH) grain emission on ∼200 pc scales. A clear change in the average grain properties between the star-forming ring and the central AGN is found. Regions in the vicinity of the AGN, with [Ne iii]/[Ne ii] > 0.25, tend to have larger grain sizes and lower aliphatic-to-aromatic (3.4/3.3) ratios, indicating that smaller grains are preferentially removed by photodestruction in the vicinity of the AGN. PAH emission at the nucleus is weak and shows a low 11.3/3.3 PAH ratio. We find an overall suppression of the total PAH emission relative to the ionized gas in the central 1 kpc region of the AGN in NGC 7469 compared to what has been observed with Spitzer on 3 kpc scales. However, the fractional 3.3 μm–to–total PAH power is enhanced in the starburst ring, possibly due to a variety of physical effects on subkiloparsec scales, including recurrent fluorescence of small grains or multiple photon absorption by large grains. Finally, the IFU data show that while the 3.3 μm PAH-derived star formation rate (SFR) in the ring is 27% higher than that inferred from the [Ne ii] and [Ne iii] emission lines, the integrated SFR derived from the 3.3 μm feature would be underestimated by a factor of 2 due to the deficit of PAHs around the AGN, as might occur if a composite system like NGC 7469 were to be observed at high redshift.

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