We describe a sample of low-mass Seyfert 2 galaxies selected from the Sloan Digital Sky Survey, having a median absolute magnitude of Mg = −19.0 mag. These galaxies are Type 2 counterparts to the Seyfert 1 galaxies with intermediate-mass black holes identified by Greene & Ho (2004). Spectra obtained with the Echellette Spectrograph and Imager at the Keck Observatory are used to determine the ce...

We use the CO band at 2.3 μm to constrain the populations of young stars in the central regions of Seyfert galaxies. We report new CO band spectroscopy of 46 Seyfert galaxies. In most cases, the observed CO indices appear diluted by the presence of a non-stellar component (most likely, warm dust surrounding the active nucleus). We used JHKL aperture photometry to estimate the non-stellar contri...

We have detected a broad Hα emission line in the polarized flux spectrum of the Seyfert 2 galaxy NGC 788, indicating that it contains an obscured Seyfert 1 nucleus. While such features have been observed in ∼ 15 other Seyfert 2s, this example is unusual because it has a higher fraction of galaxy starlight in its spectrum, a lower average measured polarization, and a significantly lower radio lu...

We present a summary of spectra of Seyfert galaxies observed by the OSSE detector aboard Compton Gamma Ray Observatory. We obtain average spectra of Seyferts of type 1 and 2, and find they are well fitted by thermal Comptonization. We present detailed parameter ranges for the plasma temperature and the Compton parameter in the case of spherical and slab geometries. We find both the average and ...

Massive Black Holes detected by in the centers of many nearby galaxies show an approximately linear relation with the luminosity of the host bulge, inferring the black hole has a mass of 0.001-0.002 of the bulge. Previous work suggested that black holes of active (Seyfert 1) galaxies follow a similar relation, but apparently with a significantly lower value of MBH/Mbulge (Wandel 1999). New data...

We present an optical spectrum for Mrk 273x, the X-ray source 1.3 to the northeast of Mrk 273. The new spectrum indicates that the object is at a much higher redshift (0.458) than the value (0.0376) previously reported by us. All the detected emission lines show properties of Seyfert 2 galaxies. Mrk 273x has one of the highest X-ray and radio luminosities (Lx ≈ 1.1 × 10 44 erg s, L1.37GHz ≈ 2.0...

To examine the relationship between black hole mass and host galaxy velocity dispersion for low black hole masses, we have measured the velocity dispersions of 15 Seyfert 1 galaxies from the catalog of Greene & Ho (2004). These Seyferts were selected from the Sloan Digital Sky Survey to have estimated black hole masses below 106 M⊙. The data are consistent with a straightforward downward extrap...

We present a preliminary analysis of the first high-resolution X-ray spectrum of a Seyfert 2 galaxy, Mkn 3, obtained with the High Energy Transmission Grating Spectrometer onboard the Chandra X-ray Observatory. The high-energy spectrum (λ . 4 Å) is dominated by reflection of the AGN continuum radiation in a cold optically thick medium and contains bright Kα fluorescent lines from iron and silic...

We present the results of a near-infrared and X-ray study of the Seyfert 2 galaxy NGC 3281. Emission from the Seyfert nucleus is detected in both regions of the electromagnetic spectrum, allowing us to infer both the equivalent line of sight hydrogen column density, NH = 71.0 +11.3 −12.3 × 10 26 m and the extinction due to dust, AV = 22 ± 11 magnitudes (90% confidence intervals). We infer a rat...

We report long, pointed ROSAT HRI observations of the hyperluminous galaxies IRAS F00235+1024, F12514+1027, F14481+4454 and F14537+1950. Two of them are optically classified as Seyfert-like. No X-ray sources are detected at the positions of any of the objects, with a mean upper limit LX/LBol ≃ 2.3 × 10 . This indicates that any active nuclei are either atypically weak at X-ray wavelengths or ob...