Related papers: Compact Radio Cores in Seyfert Galaxies
The presence of megaparsec-scale radio halos in galaxy clusters has already been established by many observations over the last two decades. The emerging explanation for the formation of these giant sources of diffuse synchrotron radio…
We present the results of a Hubble Space Telescope (HST) survey of extended [OIII] emission in a sample of 60 nearby Seyfert galaxies (22 Seyfert 1's and 38 Seyfert 2's), selected by mostly isotropic properties. The comparison between the…
Among the large varieties of active galactic nuclei (AGN) known, narrow line Seyfert 1 (NLSy1) galaxies are a puzzling class, particularly after the discovery of $\gamma$-ray emission in a handful of them using observations from the Fermi…
We present detailed scattering models confirming that distinctive variations in polarization across the broad Halpha line, which are observed in a significant fraction of Seyfert 1 galaxies, can be understood in terms of a rotating…
To constrain models of the jet-disc connection, we explore Eddington ratios reported in Foschini (2011) and interpret them in relation to the values in Sikora et al. across the active galactic nuclei population from radio loud quasars,…
We present slitless spectra of 10 Seyfert galaxies observed with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope. The spectra cover the [OIII] 4959, 5007 emission lines at a spectral resolving power of ~9000 and a…
We present the results of high resolution VLBI observations at 1.6 and 4.9 GHz of the radio-loud Seyfert galaxy, Mrk 6. These observations are able to detect a compact radio core in this galaxy for the first time. The core has an inverted…
The nuclei of Seyfert 1 galaxies exhibit a range of optical polarization characteristics that can be understood in terms of two scattering regions producing orthogonal polarizations: an extended polar scattering region (PSR) and a compact…
We present a series of statistical tests using homogeneous data and measurements for a sample of Seyfert galaxies. These galaxies were selected from mostly isotropic properties, their far infrared fluxes and warm infrared colors, which…
This paper presents 1.4-GHz radio continuum observations of 15 very extended radio galaxies. These sources are so large that most interferometers lose partly their structure and total flux density. Therefore, single-dish detections are…
We have produced radio maps, using the ATCA, of the central regions of six southern Seyfert 2 galaxies (NGC 1365, 4945, 6221, 6810, 7582, and Circinus) with circumnuclear star formation, to estimate the relative contribution of star…
The results of Chandra snapshot observations of 11 LINERs (Low-Ionization Nuclear Emission-line Regions), three low-luminosity Seyfert galaxies, and one HII-LINER transition object are presented. Our sample consists of all the objects with…
Narrow-line Seyfert 1 galaxies (NLS1s) are active galactic nuclei (AGN) recently identified as a new class of $\gamma$-ray sources. The high energy emission is explained by the presence of a relativistic jet observed at small angles, just…
We have made high-quality measurements of the polarization spectra of 13 FR II radio galaxies and taken polarization images for 11 of these with the Keck telescopes. Seven of the eight narrow-line radio galaxies (NLRG) are polarized, and…
We present archival high spatial resolution VLA and VLBA data of the nuclei of seven of the nearest and brightest Seyfert galaxies in the Southern Hemisphere. At VLA resolution (~0.1 arcsec), the nucleus of the Seyfert galaxies is…
We report the results of a 5 GHz southern hemisphere VLBI survey of compact extragalactic radio sources. These observations were undertaken with the SHEVE array plus Shanghai station in November 1992. A sample of 22 sources was observed and…
Seyfert and LINER galaxies are known to exhibit compact radio emission on $\sim$ 10 to 100 parsec scales, but larger Kiloparsec-Scale Radio structures (KSRs) often remain undetected in sub-arcsec high resolution observations. We investigate…
We present a multi-wavelength study of the radio-loud narrow line Seyfert 1 galaxy (NLSy1), 1H 0323+342, detected by Fermi Gamma Ray Space Telescope. Multi-band light curves show many orphan X-ray and optical flares having no corresponding…
We study a sample of Narrow-line Seyfert 1 galaxies (NLS1) in their optical and radio features, in order to understand the differences between their radio silent, radio-loud and radio-quiet subclasses. We first show that the different…
The role of starburst winds versus active galactic nuclei (AGN) jets/winds in the formation of the kiloparsec scale radio emission seen in Seyferts is not yet well understood. In order to be able to disentangle the role of various…