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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 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)
This paper studies systematically, for the first time, the circumgalactic environment of bright IRAS galaxies as defined by Soifer, et al. (1989). While the role of gravitational interaction for luminous and ultraluminous IRAS galaxies has been well established by various studies, the situation is by far more obscure in the IR luminosity range of the bright(More)
Accretion processes in quasars and active galactic nuclei are still poorly understood , especially as far as the connection between observed spectral properties and physical parameters is concerned. Quasars show an additional degree of complexity compared to stars that is related to anisotropic emission/obscuration influencing the observed properties in(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)
We compute the virial mass of the central black hole (M) and the luminosity-to-mass (L/M) ratio of ≈ 300 low-z quasars and luminous Seyfert 1 nuclei. We analyze: (1) whether radio-quiet and radio-loud objects show systematic differences in terms of M and L/M; (2) the influence of M and L/M on the shape of the Hβ broad component line profile; (3) the(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)
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)
Recently some pessimism has been expressed about our lack of progress in understanding quasars over the 50+ year since their discovery (Antonucci, 2013). It is worthwhile to look back at some of the progress that has been made—but still lies under the radar—perhaps because few people are working on optical/UV spectroscopy in this field. Great advances in(More)