Related papers: Active galactic nuclei among polar-ring galaxies
We have searched for CO lines in a sample of 21 new morphologically determined polar-ring galaxies (of which nine are kinematically confirmed), obtained from a wide search in the Galaxy Zoo project by Moiseev and collaborators. Polar-ring…
It has long been suspected that Active Galactic Nuclei are powered by accretion of matter onto massive black holes and this belief implies their presence in the nuclei of most nearby galaxies as "relics" of past activity. Just a few years…
Polar-ring galaxies are photometrically and kinematically decoupled systems which are highly inclined to the major axis of the host galaxy. These objects have been explored since the 1970s, but the rarity of these systems has made such…
Optical spectropolarimetry and broadband polarimetry in other wavebands has been a key to understanding many diverse aspects of AGN. In some cases polarization is due to synchrotron radiation, and in other cases it's due to scattering.…
Polar ring galaxies are flattened stellar systems with an extended ring of gas and stars rotating in a plane almost perpendicular to the central galaxy. We show that their formation can occur naturally in a hierarchical universe where most…
We demonstrate that the scatter in the luminosity relations of astrophysical objects can be used to search for axion-like-particles (ALPs). This analysis is applied to observations of active galactic nuclei, where we find evidence strongly…
Formation scenarios for polar ring galaxies are studied through N-body simulatio ns that are compared with existing observations. It is shown that polar rings ar e likely to be formed by tidal accretion of the polar material from a gas rich…
An unprecedentedly large number of LINERs has been discovered in a recently completed optical spectroscopic survey of nearby galaxies, allowing several statistical properties of the host galaxies and of the line-emitting regions to be…
The existence of correlations between nuclear properties of galaxies, such as the mass of their central black holes, and larger scale features, like the bulge mass and luminosity, represent a fundamental constraint on galaxy evolution.…
Galaxy interactions are studied in terms of the starburst-Seyfert connection. The starburst requires a high rate of gas supply. Since the efficiency for supplying the gas is high in a galaxy interaction, although the companion is not…
We use a recent near-infrared imaging survey of samples of Seyfert and normal galaxies to study the role of bars in the fueling of nuclear activity. The active galaxy sample includes Seyfert galaxies in the Revised Shapely-Ames (RSA) and…
Seyfert nuclei are typical active galactic nuclei (AGNs) in the local universe, which are thought to be powered by gas accretion onto a supermassive black hole (SMBH). The dynamical effect exerted either by non-axisymmetric gravitational…
This paper is the last in a series, investigating the optical properties of a sample of mid-IR Warm Seyfert galaxies and of a control sample of mid-IR cold galaxies. In the present paper we parametrize the morphologies and interaction…
We have considered polar ring galaxy candidates, the images of which can be found in the SDSS. The sample of 78 galaxies includes the most reliable candidates from the SPRC and PRC catalogs, some of which already have kinematic…
We summarize some recent results from our observational campaign to study the central regions of spiral galaxies of late Hubble type (Scd - Sm). These disk-dominated, bulgeless galaxies have an apparently uneventful merger history. The…
Representative results of a search for structures suggestive of shocked gas in the circumnuclear regions of Seyfert galaxies are presented. At issue is whether we can identify regions that appear to be shocked by outflows from the active…
In order to characterize the amount of recent or ongoing stellar formation in the circumnuclear region of active galaxies on a statistically sound basis, we have studied the stellar component of the nuclear spectra in three different…
Mergers between gas--rich disks and less--massive dwarf galaxies are studied using numerical simulation. As the orbit of a satellite decays through dynamical friction, the primary disk develops large-amplitude spirals in response to its…
Although it is clear that the circumnuclear regions of galaxies are intimately related to their host galaxies, most directly through their bars, it remains unclear what exactly initiates and fuels nuclear stellar (starburst) and non-stellar…
Galaxies are usually classified as star forming or active by using diagnostic diagrams, such as [N II]/Halpha vs. [O III]/Hbeta. Active galaxies are further classified into Seyfert or LINER-like sources. We claim that a non-negligible…