Radio morphology of southern narrow-line Seyfert 1 galaxies with Very Large Array observations
: S. Chen, E. Järvelä, L. Crepaldi, M. Zhou, S. Ciroi, M. Berton, P. Kharb, L. Foschini, M. Gu, G. La Mura, A. Vietri
: 2020
Monthly Notices of the Royal Astronomical Society
: 498
: 1
: 1278
: 1297
: 20
: 0035-8711
: 1365-2966
DOI: https://doi.org/10.1093/mnras/staa2373
: https://research.utu.fi/converis/portal/detail/Publication/50366315
We present the results of new radio observations carried out with the Karl G. Jansky Very Large Array C-configuration at 5.5 GHz for a sample of southern narrow-line Seyfert 1 galaxies (NLS1s). This work increases the number of known radio-detected NLS1s in the Southern hemisphere, and confirms that the radio emission of NLS1s is mainly concentrated in a central region at kpc-scale and only a few sources show diffuse emission. In radio-quiet NLS1s, the radio luminosity tends to be higher in steep-spectrum sources and be lower in flat-spectrum sources, which is opposite to radio-loud NLS1s. This may be because the radio emission of steep NLS1s is dominated by misaligned jets, active galactic nucleus driven outflows, or star formation superposing on a compact core. Instead the radio emission of flat NLS1s may be produced by a central core that has not yet developed radio jets and outflows. We discover new NLS1s harbouring kpc-scale radio jets and confirm that a powerful jet does not require a large-mass black hole to be generated. We also find sources dominated by star formation. These NLS1s could be new candidates in investigating the radio emission of different mechanisms....
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