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We derive black hole masses for a sample of about 300 AGNs in the redshift range 0 < z < 2.5. We use the same virial velocity measure (FWHM HβBC) for all sources which represents a significant improvement over previous studies. We review methods and caveats for determining AGN black hole masses via the virial assumption for motions in the gas producing low(More)
Recent work has shown that it is possible to systematize quasar spectral diversity in a parameter space called " Eigenvector 1 " (E1). We present median AGN spectra for fixed regions of the E1 (optical) parameter space (FWHM(Hβ) vs. equivalent width ratio R FeII =W(FeII λ4570)/W(Hβ). Comparison of the median spectra for different regions show considerable(More)
We search for a dichotomy/bimodality between Radio Loud (RL) and Radio Quiet (RQ) Type 1 Active Galactic Nuclei (AGN). We examine several samples of SDSS QSOs with high S/N optical spectra and matching FIRST/NVSS radio observations. We use the radio data to identify the weakest RL sources with FRII structure to define a RL/RQ boundary which corresponds to(More)
We investigate the radial velocity difference between the [OIII]λλ4959,5007 and Hβ lines for a sample of ≈ 200 low redshift AGN. We identify seven objects showing an [OIII]λ5007 blueshift relative to Hβ with amplitude larger than 250 km s −1 (blue " outliers "). These line shifts are found in sources where the broad high ionization lines (e.g. CIVλ1549)(More)
We identify a correlation space involving optical and UV emission line parameters as well as the soft X-ray spectral index that provides optimal discrimination between all principal classes of active galactic nuclei. Most of the sources in our three high quality data samples show a strong intercorrelation with narrow line Seyfert 1 (NLSy1) galaxies and(More)
We present composite UV spectra for low redshift Type 1 AGN binned to exploit the information content of the Eigenvector 1 (E1) parameter space. Composite spectra show high enough S/N and spectral resolution to permit a decomposition of the Civλ1549 line profile – one of the strongest high-ionization lines (HIL) and fundamental in defining E1 space. The(More)
We present high S/N spectra of the Hβ region in 17 intermediate redshift (0.85 ≤ z ≤ 2.5) quasars. The spectra represent first results of our campaign to test the redshift/luminosity robustness of the so-called Eigenvector 1 (E1) parameter space as developed for low redshift AGN in Sulentic et al. (2000b). The new quasars span the luminosity range −26 ≥ M B(More)
RESUMEN Revisamos las limitaciones que se pueden imponer a partir de las observa-ciones, sobre los modelos de la estructura de las regiones que emiten las lineas anchas en los Núcleos Activos de Galaxias. La comparación entre las lineas de baja-y alta ionización, sugiere que la emisión proviene, en parte, de una geometría fuertemente aplanada (el disco de(More)
The last decade saw long-awaited improvements in our understanding of active galactic nuclei (AGN) spectral properties. This contribution reviews some important observational results obtained from optical and UV data as well as constraints on physical parameters that control the structure and dynamics of the Broad Line Region. 1. INTRODUCTION " A thousand(More)
The 4D Eigenvector 1 parameter space was introduced seven years ago as an attempt at multiwavelength spectroscopic representation of quasars. It appears to be the most effective diagnostic space for unifying the diversity of broad line AGN. This progress report shows that the diagnostic power of 4DE1 is confirmed using optical spectra from the SDSS, UV(More)