GOALS-JWST: Small neutral grains and enhanced 3.3 micron PAH emission in the Seyfert galaxy NGC 7469
| Autor: | Lai, Thomas S. -Y., Armus, Lee, Bianchin, Marina, Diaz-Santos, Tanio, Linden, Sean T., Privon, George C., Inami, Hanae, U, Vivian, Bohn, Thomas, Evans, Aaron S., Larson, Kirsten L., Hensley, Brandon S., Smith, J. -D. T., Malkan, Matthew A., Song, Yiqing, Stierwalt, Sabrina, van der Werf, Paul P., McKinney, Jed, Aalto, Susanne, Buiten, Victorine A., Rich, Jeff, Charmandaris, Vassilis, Appleton, Philip, Barcos-Munoz, Loreto, Boker, Torsten, Finnerty, Luke, Kader, Justin A., Law, David R., Brown, Michael J. I., Hayward, Christopher C., Howell, Justin, Iwasawa, Kazushi, Kemper, Francisca, Marshall, Jason, Mazzarella, Joseph M., Muller-Sanchez, Francisco, Murphy, Eric J., Sanders, David, Surace, Jason |
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| Rok vydání: | 2023 |
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| Druh dokumentu: | Working Paper |
| Popis: | 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 um neutral polycyclic aromatic hydrocarbon (PAH) grain emission on ~60 pc scales. We find a clear change in the average grain properties between the star-forming ring and the central AGN. Regions in the vicinity of the AGN, with [NeIII]/[NeII]>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 photo-destruction in the vicinity of the AGN. 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 um to total PAH power is enhanced in the starburst ring, possibly due to a variety of physical effects on sub-kpc scales, including recurrent fluorescence of small grains or multiple photon absorption by large grains. Finally, the IFU data show that while the 3.3 um PAH-derived star formation rate (SFR) in the ring is 8% higher than that inferred from the [NeII] and [NeIII] emission lines, the integrated SFR derived from the 3.3 um feature would be underestimated by a factor of two 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. Comment: 14 pages, 5 figures, 2 tables, Submitted to ApJL |
| Databáze: | arXiv |
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