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An 8.4-GHz Long Baseline Array observation of the unusual Seyfert galaxy NGC 7213 |
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| Authors: | D L Blank J I Harnett P A Jones |
| Institution: | School of Engineering and Industrial Design, University of Western Sydney, Penrith South DC, NSW 1797, Australia;Faculty of Engineering, University of Technology Sydney, PO Box 123, Broadway, NSW 2007, Australia;Australia Telescope National Facility, PO Box 76, Epping, NSW 2121, Australia |
| Abstract: | We have observed the type 1.5 Seyfert galaxy NGC 7213 with the Australian Long Baseline Array (LBA) at 8.4 GHz to discover whether this object has the high brightness temperature compact core suggested by low-frequency variability. Confirmation would support the hypothesis that radio-intermediate Seyfert galaxies have Doppler-boosted radio jets. Our observation confirms the existence of this core but with a flux density of almost a factor of 6 less than observed 12 yr earlier. Though few studies exist on the long-term radio variability of Seyferts, a decline of this magnitude does appear to be rare. |
| Keywords: | techniques: interferometric galaxies: individual: NGC 7213 galaxies: Seyfert radio continuum: galaxies |