2003/01/01 by Seiji Kameno, Makoto Inoue, Kiyoaki Wajima +3 · 7 citations
Physics and Astronomy · #Absorption (acoustics) #Absorption spectroscopy #Active galactic nucleus #Astronomy and Astrophysical Research #Galaxies: Formation, Evolution, Phenomena #Jet (fluid) #Opacity #Quasar #Radio Astronomy Observations and Technology #Type (biology) #astro-ph
paper · pdf · doi:10.1071/as03037
published in Publications of the Astronomical Society of Australia 20(1), 213-221 (Cambridge University Press) · 17 pages, including 8 figures. Proceedings of the 3rd Compact Steep Spectrum and GHz Peaked Spectrum Sources, 2002, Greece. Submitted to the Publications of Astronomical Society of Australia
openalex publication_date 2003/01/01 · arxiv created 2003/02/13 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Abstract We report very long baseline array (VLBA) observations at 2.3, 8.4, and 15.4 GHz towards nine gigahertz peaked spectrum (GPS) sources. One Seyfert 1 galaxy, one Seyfert 2 galaxy, three radio galaxies, and four quasars were included in our survey. We obtained spatial distributions of the free–free absorption (FFA) opacity with milliarcsecond resolution for all sources. It is found that type 1 (Seyfert 1 and quasars) and type 2 (Seyfert 2 and radio galaxies) sources showed different distributions of the FFA opacities. The type 1 sources tend to show more asymmetric opacity distributions towards a double lobe, while those of the type 2 sources are rather symmetric. Our results imply that the different viewing angle of the jet causes the difference of FFA opacity along the external absorber. This idea supports the unified scheme between quasars and radio galaxies, proposed by Barthel (1989).