On the nature of the near-UV extended light in Seyfert galaxies |
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Authors: | V M Muñoz Marín T Storchi-Bergmann R M González Delgado H R Schmitt P F Spinelli E Pérez R Cid Fernandes |
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Institution: | Instituto de Astrofísica de Andalucía (IAA-CSIC), Granada, Spain;Instituto de Física, Universidade Federal do Rio Grande do Sul, IF, CP 15051, Porto Alegre 91501-970, RS, Brazil;Naval Research Laboratory, Remote Sensing Division, Code 7215, 4555 Overlook Ave. SW, Washington, DC 20375, USA;Interferometrics, Inc, 13454 Sunrise Valley Drive, Suite 240, Herndon, VA 20171, USA;Universitätssternwarte München, D-81679 München, Germany;Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil |
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Abstract: | We study the nature of the extended near-UV emission in the inner kiloparsec of a sample of 15 Seyfert (Sy) galaxies which have both near-UV (F330W) and narrow-band O iii ] high-resolution Hubble images. For the majority of the objects, we find a very similar morphology in both bands. From the O iii ] images, we construct synthetic images of the nebular continuum plus the emission-line contribution expected through the F330W filter, which can be subtracted from the F330W images. We find that the emission of the ionized gas dominates the near-UV extended emission in half of the objects. A further broad-band photometric study, in the bands F330W ( U ), F547M ( V ) and F160W ( H ), shows that the remaining emission is dominated by the underlying galactic bulge contribution. We also find a blue component whose nature is not clear in four out of 15 objects. This component may be attributed to scattered light from the active galactic nuclei, to a young stellar population in unresolved star clusters, or to early disrupted clusters. Star-forming regions and/or bright off nuclear star clusters are observed in 4/15 galaxies of the sample. |
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Keywords: | galaxies: nuclei galaxies: Seyfert ultraviolet: galaxies |
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