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arXiv · 0704.3836

Japanese VLBI Network observations of radio-loud narrow-line Seyfert 1 galaxies

Akihiro Doi·Kenta Fujisawa·Makoto Inoue·Kiyoaki Wajima·Hiroshi Nagai·Keiichiro Harada·Kousuke Suematsu·Asao Habe·Mareki Honma·Noriyuki Kawaguchi·Eiji Kawai·Hideyuki Kobayashi·Yasuhiro Koyama·Hiromitsu Kuboki·Yasuhiro Murata·Toshihiro Omodaka·Kazuo Sorai·Hiroshi Sudou·Hiroshi Takaba·Kazuhiro Takashima·Koji Takeda·Sayaka Tamura·Ken-ichi Wakamatsu
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Abstract

We performed phase-reference very long baseline interferometry (VLBI) observations on five radio-loud narrow-line Seyfert 1 galaxies (NLS1s) at 8.4 GHz with the Japanese VLBI Network (JVN). Each of the five targets (RXS J08066+7248, RXS J16290+4007, RXS J16333+4718, RXS J16446+2619, and B3 1702+457) in milli-Jansky levels were detected and unresolved in milli-arcsecond resolutions, i.e., with brightness temperatures higher than 10^7 K. The nonthermal processes of active galactic nuclei (AGN) activity, rather than starbursts, are predominantly responsible for the radio emissions from these NLS1s. Out of the nine known radio-loud NLS1s, including the ones chosen for this study, we found that the four most radio-loud objects exclusively have inverted spectra. This suggests a possibility that these NLS1s are radio-loud due to Doppler beaming, which can apparently enhance both the radio power and the spectral frequency.

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Akihiro Doi, Kenta Fujisawa, Makoto Inoue, Kiyoaki Wajima, Hiroshi Nagai, Keiichiro Harada, Kousuke Suematsu, Asao Habe, Mareki Honma, Noriyuki Kawaguchi, Eiji Kawai, Hideyuki Kobayashi, Yasuhiro Koyama, Hiromitsu Kuboki, Yasuhiro Murata, Toshihiro Omodaka, Kazuo Sorai, Hiroshi Sudou, Hiroshi Takaba, Kazuhiro Takashima, Koji Takeda, Sayaka Tamura, Ken-ichi Wakamatsu. 2007-04-29. Japanese VLBI Network observations of radio-loud narrow-line Seyfert 1 galaxies. https://doi.org/10.1093/pasj%2F59.4.703

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