著者

Doi Akihiro Nagira Hiroshi Kawakatu Nozomu Kino Motoki Nagai Hiroshi Asada Keiichi

出版者

IOP Publishing

雑誌

Astrophysical journal (ISSN:0004637X)

巻号頁・発行日

vol.760, no.1, pp.41, 2012-11

被引用文献数

76

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We report the finding of kiloparsec (kpc)-scale radio structures in three radio-loud narrow-line Seyfert 1 (NLS1) galaxies from the Faint Images of the Radio Sky at Twenty-centimeters of the Very Large Array, which increases the number of known radio-loud NLS1s with kpc-scale structures to six, including two γ-ray-emitting NLS1s (PMN J0948+0022 and 1H 0323+342) detected by the Fermi Gamma-ray Space Telescope. The detection rate of extended radio emissions in NLS1s is lower than that in broad-line active galactic nuclei (AGNs) with a statistical significance. We found both core-dominated (blazar-like) and lobe-dominated (radio-galaxy-like) radio structures in these six NLS1s, which can be understood in the framework of the unified scheme of radio-loud AGNs that considers radio galaxies as non-beamed parent populations of blazars. Five of the six NLS1s have (1) extended radio luminosities suggesting jet kinetic powers of gsim 1044 erg s–1, which is sufficient to make jets escape from hosts' dense environments; (2) black holes of gsim 107 M ☉, which can generate the necessary jet powers from near-Eddington mass accretion; and (3) two-sided radio structures at kpc scales, requiring expansion rates of ~0.01c-0.3c and kinematic ages of gsim 107 years. On the other hand, most typical NLS1s would be driven by black holes of lsim 107 M ☉ in a limited lifetime of ~107 years. Hence, the kpc-scale radio structures may originate in a small window of opportunity during the final stage of the NLS1 phase just before growing into broad-line AGNs.