Related papers: The Narrow Line Region: Current Models and Future …
Based on photoionization calculations we present a study of the NLR emission line ratios of Narrow-line Seyfert 1 (NLS1) galaxies. In particular, we investigate the influence of different EUV - soft-X-ray spectral shapes (a giant soft…
Indirectly resolving the line-emitting gas regions in distant Active Galactic Nuclei (AGN) requires both high-resolution photometry and spectroscopy (i.e. through reverberation mapping). Emission in AGN originates on widely different…
Active galactic nuclei (AGN) can launch outflows of ionized gas that may influence galaxy evolution, and quantifying their full impact requires spatially resolved measurements of the gas masses, velocities, and radial extents. We previously…
The narrow emission line spectra of active galactic nuclei are not accurately described by simple photoionization models of single clouds. Recent Hubble Space Telescope images of Seyfert 2 galaxies show that these objects are rich with…
This paper presents a comparative study of emission line ratios of the Narrow Line Region (NLR) of Seyfert 1 and Seyfert 2 galaxies. It includes a literature compilation of the emission line fluxes [OII]3727A, [NeIII]3869A, [OIII]5007A and…
Ionization cones and relativistic jets give us one of the most large-scale example of active galactic nuclei (AGN) influence on the surrounding gas environment in galaxies and beyond. The study of ionization cones makes it possible not only…
We present dynamical models of the narrow line region (NLR) outflows in the nearby Seyfert galaxies Mrk 3, Mrk 78, NGC 1068, and NGC 4151 using observations from the Hubble Space Telescope and Apache Point Observatory. We employ long-slit…
I provide a short review of the properties of Narrow-line Seyfert 1 (NLS1) galaxies across the electromagnetic spectrum and of the models to explain them. Their continuum and emission-line properties manifest one extreme form of Seyfert…
Thanks to the execution of extensive spectroscopic surveys that have covered large fractions of the sky down to magnitudes as faint as $i \approx 19$, it has been possible to identify several narrow-line Seyfert 1 galaxies (NLS1s) and to…
The strong broad emission lines in the optical and UV spectra of Active Galactic Nuclei (AGN) are important for several reasons. Not only do they give us information about the structure of the AGN, their properties are now used to estimate…
We have combined HST/FOS and ground-based spectra of the Seyfert 1 galaxy NGC 5548 to study the narrow emission lines over the 1200 -- 10,000 angstrom region. All of the spectra were obtained when the broad emission line and continuum…
Gas metallicity, ionization parameter, and gas pressure can affect the observed ratios of specific strong emission lines within galaxies. While the theoretical strong lines diagnostics for gas metallicity, ionization parameters, and gas…
Our aim is to explore the nature of emission line galaxies by combining high-resolution observations obtained in different bands to understand which objects are powered by an Active Galactic Nucleus(AGN). From the spectroscopic Palomar…
The narrow-line region (NLR) consists of gas clouds ionized by the strong radiation from the active galactic nucleus (AGN), distributed in the spatial scale of AGN host galaxies. The strong emission lines from the NLR are useful to diagnose…
In this paper a discussion of kinematics and physics of the Broad Line Region (BLR) is given. The possible physical conditions in the BLR and problems in determination of the physical parameters (electron temperature and density) are…
Seyfert narrow line regions (NLR) have emission line ratios which are remarkably uniform, displaying only ~0.5 dex variation between different galaxies. Existing models have been unable to explain these observations without the introduction…
The impact of active galactic nuclei on low-ionization nuclear emission-line regions (LINERs) remains a vigorous field of study. We present preliminary results from a study of the mid-infrared atomic emission lines of LINERs with the…
We present an investigation of the structure of the emission line region in a sample of 12 single-peaked Active Galactic Nuclei (AGNs). Using the high resolution H-beta and H-alpha line profiles observed with the Isaac Newton Telescope (La…
In recent surveys of Radio-loud AGN, a new sub-class of objects, known as Weak-Line Radio Galaxies (WLRGs) has emerged. These radio galaxies have only weak, low-ionization optical emission lines. In the X-ray band, these objects are much…
The narrow line region of active galaxies is formed by gas clouds surrounded by a diluted gas. Standard one-dimensional photoionization models are usually used to model this region in order to reproduce the observed emission lines. Since…