Near-infrared morphologies of the host galaxies of narrow-line Seyfert 1 galaxies

We present J-band near-infrared (NIR) imaging of the host galaxies of nine narrow-line Seyfert 1 galaxies (NLS1). Based on high-frequency radio observations at 37 GHz, seven of them could host powerful jets that are most likely relativistic. Host galaxy morphology studies of NLS1 galaxies are scarce...

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Bibliographic Details
Published in:Astronomy and astrophysics (Berlin) 2018-11, Vol.619, p.A69
Main Authors: Järvelä, E., Lähteenmäki, A., Berton, M.
Format: Article
Language:English
Subjects:
Active galactic nuclei
Decomposition
Galactic bulge
Galactic evolution
galaxies: active
galaxies: Seyfert
galaxies: structure
Infrared imaging
infrared: galaxies
Morphology
Photometry
Radio astronomy
Radio observation
Seyfert galaxies
Spiral galaxies
Two dimensional models
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Summary:We present J-band near-infrared (NIR) imaging of the host galaxies of nine narrow-line Seyfert 1 galaxies (NLS1). Based on high-frequency radio observations at 37 GHz, seven of them could host powerful jets that are most likely relativistic. Host galaxy morphology studies of NLS1 galaxies are scarce, but exceedingly important for understanding the seemingly heterogeneous nature of the NLS1 population as well as their evolution and place in the active galactic nuclei (AGN) scheme. Increasing the sample size is essential for achieving statistically significant results. We determine the morphological types of the host galaxies by performing photometric decomposition of NIR images using a 2D image decomposition algorithm GALFIT. We were able to sufficiently model five of the nine host galaxies. Based on the fitting parameters, mainly the Sérsic index, all five are disk-like galaxies. Sources with clearly distinguishable bulge components all have pseudo-bulges, and four out of five sources show a component resembling a bar. A surprisingly large fraction, three out of five, show signs of interaction or disturbed morphology. Our results suggest that spiral galaxies with pseudo-bulges are able to launch and maintain powerful jets. They also imply that interaction – mainly minor mergers – may have a role in initially triggering higher levels of nuclear activity in NLS1 galaxies. Furthermore, our results support the heterogeneous nature of the NLS1 class and indicate that this diversity is caused by different evolutionary stages, possibly due to mergers.
ISSN:0004-6361
1432-0746
DOI:10.1051/0004-6361/201832876