We are conducting the first systematic 3D spectroscopic imaging survey to quantify the properties of the atomic gas (Hi) in a distance-limited sample of 28 Seyfert galaxies and a sample of 28 inactive control galaxies with well-matched optical properties (the VHIKINGS survey). This study aims to address the role of the host galaxy in nuclear activity and confront outstanding controversies in op...

We present new spectropolarimetry of a sample of nearby Compton-thin Seyfert 2 galaxies (ie those with N H < 10 23 cm −2). We show that the detection rate of scattered broad Hα in this sample is considerably higher than in Seyfert 2 galaxies as a whole. Our results also show that in this low obscuration set it is possible to find scattered broad Hα even when the global properties of the galaxy ...

We show that the sharp cutoff in the hard X-ray spectrum of NGC 4151, unusual for Seyfert 1 galaxies, can be reconciled with the average Seyfert 1 spectrum if we assume that the central source is completely hidden from our line of sight by the thick part of the accretion disk or by the broad emission line clouds. The observed X-ray radiation is produced by scattering of the Seyfert 1-type spect...

We present a Hubble Space Telescope (HST) survey of extended [OIII] emission for a sample of 60 Seyfert galaxies (22 Seyfert 1’s and 38 Seyfert 2’s), selected based on their far infrared properties. The observations for 42 of these galaxies were done in a snapshot survey with WFPC2. The remaining 18 were obtained from the HST archive, most of which were observed with the same configuration. The...

Obscured active galactic nuclei, which are classified optically as type 2 (narrow-line) Seyfert galaxies in the local universe, are by far the most promising candidates for the origin of the hard (2–10 keV) X-ray background radiation. However, optical follow-up observations of faint X-ray sources in deep Chandra images have revealed surprising numbers of apparently normal galaxies at modest red...

We report Very-Long-Baseline Array (VLBA) observations at 2.3, 8.4, and 15.4 GHz towards nine GHz-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 milliarcsec resolutions for all sources. It is found that type-1 (Seyfert 1...

Feedback from black hole activity is widely believed to play a key role in regulating star formation and black hole growth. A long-standing issue is the relation between the star formation and fueling the supermassive black holes in active galactic nuclei (AGNs). We compile a sample of 57 Seyfert galaxies to tackle this issue. We estimate the surface densities of gas and star formation rates in...

We describe new optical images and spectra of POX 52, a dwarf galaxy with an active nucleus that was originally detected in the POX objective-prism survey. While POX 52 was originally thought to be a Seyfert 2 galaxy, the new data reveal an emission-line spectrum very similar to that of the dwarf Seyfert 1 galaxy NGC 4395, with broad components to the permitted line profiles, and we classify PO...

We show that the X-ray power density spectra do not simply scale linearly with the mass of the black hole over many decades. Nevertheless, the high frequency tail of the power density spectrum can be successfully used for determination of the black hole mass in an AGN if another AGN is used as a reference. We determine the masses of the black holes in 6 Broad Line Seyfert 1 galaxies, 5 Narrow L...

The Spitzer IRS high resolution spectra of about 90 Seyfert galaxies from the 12μm Galaxy Sample are presented and discussed. These represent about 70% of the total complete sample of local Seyfert galaxies. The presence of starburst components in these galaxies can be quantified by powerful mid-IR diagnostics tools (i.e. 11.25μm PAH feature equivalent width and the H2 emission line intensity) ...