We present optical spectra for new infrared Seyfert galaxies obtained with the 2.16m telescope at Beijing Astronomical Observatory (BAO). After wavelength and flux calibration, they are classified by the degree of nuclear activity: nine Seyfert 2 and three Seyfert 3 galaxies. In addition, by using the data from de Grijp et al.(1992), we find that (1) there exists a tight correlation between lum...

We present Spitzermid-infrared spectra of 12 Seyfert 1.8 and 1.9 galaxies over the 5Y38 m region. We compare the spectral characteristics of this sample to those of 58 Seyfert 1 and 2 galaxies from the Spitzer archives. An analysis of the spectral shapes, the silicate 10 m feature and the emission-line fluxes have enabled us to characterize the midIR properties of Seyfert 1.8/1.9s. We find that...

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 Sandage & Tammann’s (1987) extension to this catalog. The normal galaxies were selected to match the Seyfert sample in Hubble type, redshift, inclination and b...

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 potential (such as a stellar bar) or by interaction with other galaxies has been often considered to cause the efficient gas fueling. However, recent systemati...

Using all available major samples of Seyfert galaxies and their corresponding closely matched control samples of nonactive galaxies, we find that the bar ellipticities (or axial ratios) in Seyfert galaxies are systematically different from those in nonactive galaxies. Overall, there is a deficiency of bars with large ellipticities (i.e., "thin" or "strong" bars) in Seyfert galaxies compared to ...

We have used the 15-m Swedish European Southern Observatory (ESO) Submillimetre Telescope (SEST) to observe the J = 1 → 0 and J = 2 → 1 transition lines of CO in 30 Southern hemisphere Seyfert galaxies from the extended 12-μm sample of Rush, Malkan & Spinoglio. We detected CO J = 1 → 0 in 16 out of the 30 Seyfert galaxies and CO J = 2 → 1 in 17 out of the 30 Seyfert galaxies. From the observed ...

An optical spectropolarimetric study has shown that the detectability of polarised broad Hα in Seyfert 2 galaxies is correlated to the IRAS f 60 /f 25 flux ratio where only those Seyfert 2s with " warm " IRAS colours show polarised broad line emission. It was suggested that those Seyfert 2s with " cool " IRAS colours have highly inclined tori which obscure the broad line scattering screen. I pr...

The nature of the UV-Optical continuum in Seyfert 2 galaxies is a matter of current debate, fundamental to which is the issue of characterizing and quantifying the stellar population contribution to the nuclear spectra. Using high S/N long-slit spectroscopy of a sample of 20 Seyfert 2 galaxies, we have applied a novel approach to investigate the nuclear stellar population in these galaxies. Our...

Unified models of Seyfert galaxies, based on viewing angles, successfully explain the observed differences between type 1 and 2 Seyferts. The existence of a range in accretion rates (ṁ ∼ 0.001− 1) relative to the Eddington rate (from broad-line Seyfert 1s to narrow-line Seyfert 1s or NLS1s) and the unification of Seyfert galaxies imply that there must be type 2 counterparts of NLS1 galaxies i.e...

We present nuclear spectral energy distributions (SEDs) in the range 0.4−16μm for an expanded CfA sample of Seyfert galaxies. The spectral indices (fν ∝ ν IR) from 1−16μm range from αIR ∼ 0.9 to 3.8. The shapes of the spectra are correlated with Seyfert type in the sense that steeper nuclear SEDs (νfν increasing with increasing wavelength) tend to be found in Seyfert 2s and flatter SEDs (νfν ≃ ...