Near-infrared spectroscopy of eight high-redshift powerful radio galaxies (jrest D 3700È6800 AŽ ) (HzPRGs) at z\ 2.2È2.6 is presented. Strong forbidden lines and Ha emission were detected in all sources ; the data show evidence that the emission lines of the HzPRGs may contribute a substantial fraction (D25%È98%) of their total observed Hand/or K-band light. Diagnostic emission-line ratiosÈ [O ...

We report the discovery of X-ray emission from a radio knot at a projected distance of 25′′ from the nucleus of the Seyfert galaxy, 3C 120. The data were obtained with the ROSAT High Resolution Imager (HRI). Optical upper limits for the knot preclude a simple power law extension of the radio spectrum and we calculate some of the physical parameters for thermal bremsstrahlung and synchrotron sel...

We construct near-infrared to visible broad band NICMOS/WFPC color maps for 4 early-type Seyfert galaxies with S-shaped or one-sided ionization cones. We find that dust lanes are near or connected to many of the features seen in the [OIII] and Hα+[NII] line emission maps. This suggests that much of the structure of line emission in these ionization cones is determined by the distribution of amb...

X-ray spectra of Seyfert galaxies have revealed a new type of X-ray spectral feature, one which appears to offer important new insight into the black hole system. XMM revealed several narrow emission lines redward of Fe Kα in NGC 3516. Since that discovery the phenomenon has been observed in other Seyfert galaxies, e.g. NGC 7314 and ESO 198-G24. We present new evidence for a redshifted Fe line ...

We report X-ray fluxes in the 2–10 keV band from LINERs (low-ionization nuclear emission-line regions) and low-luminosity Seyfert galaxies obtained with the ASCA satellite. Observed X-ray luminosities are in the range between 4×10 and 5×10 ergs s, which are significantly smaller than that of the “classical” low-luminosity Seyfert 1 galaxy NGC 4051. We found that X-ray luminosities in 2–10 keV o...

From a sample of 50 predominantly inactive galaxies with direct supermassive black hole mass measurements, it has recently been established that barred galaxies tend to reside rightward of the Mbh-σ relation defined by non-barred galaxies. Either black holes in barred galaxies tend to be anaemic or the central velocity dispersions in these galaxies have a tendency to be elevated by the presence...

Many nearby early-type (elliptical and S0) galaxies contain weak (milli-Jansky level) nuclear radio sources on scales a few hundred parsecs or less. The origin of the radio emission, however, has remained unclear, especially in volume-limited samples that select intrinsically less luminous galaxies. Both active galactic nuclei and nuclear star formation have been suggested as possible mechanism...

We present diffraction-limited, 10 mm imaging polarimetry data for the central regions of the archetypal Seyfert active galactic nucleus NGC 1068. The position angle of polarization is consistent with three dominant polarizing mechanisms. We identify three distinct regions of polarization: (1) north of the nucleus, arising from aligned dust in the narrow emission line region, (2) south, east, a...

In order to improve the reverberation-mapping based estimate of the mass of the central supermassive black hole in the Seyfert 1 galaxy NGC 4151, we have reanalyzed archival ultraviolet monitoring spectra from two campaigns undertaken with the International Ultraviolet Explorer. We measure emission-line time delays for four lines, C IVλ1549, He IIλ1640, C III]λ1909, and Mg IIλ2798, from both ca...

Emission-line variability data on NGC 5548 argue strongly for the existence of a mass of order 7× 107 M within the inner few light days of the nucleus in the Seyfert 1 galaxy NGC 5548. The time-delayed response of the emission lines to continuum variations is used to infer the size of the line-emitting region, and these determinations are combined with measurements of the Doppler widths of the ...