Related papers: Modeling the Warm Absorber in AGN
Warm absorber spectra contain bound-bound and bound-free absorption features seen in the X-ray and UV spectra from many active galactic nuclei (AGN). The widths and centroid energies of these features indicate they occur in outflowing gas,…
Recent modeling of the warm absorber in active galactic nuclei has proved the usefulness of constant total (gas plus radiation) pressure models, which are highly stratified in temperature and density. We explore the consistency of those…
We present a method that allows us to estimate the distance from the continuum source located in the center of AGN to the highly ionized gas called warm absorber. We compute a set of constant total pressure photoionization models compatible…
Warm absorbers are found in many AGN and consist of clouds moving at moderate radial velocities, showing complex ionization structures and having moderate to large column densities. Using 1D numerical calculations, we confirm earlier…
Warm absorbers and related phenomena are one of the observable manifestations of outflows or winds from active galactic nuclei (AGN). Warm absorbers are common in low luminosity AGN, they have been extensively studied observationally, and…
In recent years it has become clear that understanding the absorption present in AGN is essential given its bearing on unification models. We present the most recent XMM-Newton observation of Mrk 6, with the goal of understanding the nature…
Although soft X-ray absorption features in AGN were discovered almost ten years ago, the nature and location of the gas creating them has remained controversial. However, by making use of the newly-available high-resolution spectra provided…
Warm absorber (WA) is an ionised gas present in the line of sight to the AGN central engine. The effect of the absorber is imprinted in the absorption lines observed in X-ray spectra of AGN. In this work, we model the WA in Seyfert 1 galaxy…
The Absorption Measure Distribution (AMD) in the X-ray outflows of Seyfert active galactic nuclei (AGN) describes the distribution of absorbing column density as a function of ionization parameter. Up to now, AMD has been measured only for…
We report on the performance of the statistical, X-ray absorption lines identification procedure XLINE-ID. As illustration, it is used to estimate the time averaged gas density $n_H(r)$ of a representative AGN's warm absorber ($T\approx…
The most common observed feature of the X-ray outflows in active galactic nuclei (AGN) is their broad ionization distribution spanning up to $\sim$ 5 orders of magnitude in ionization levels. This feature is quantified in terms of…
Recent {\it ASCA} observations confirm the presence of X-ray absorption due to partially ionized gas in many Seyfert 1 galaxies; the so-called warm absorber. Constraints on the location of the warm material are presented with the conclusion…
A number of emission and absorption features are expected to be visible in high energy resolution X-ray spectra of type 1 AGN with ionized gas along the line of sight (so called "warm absorbers"). Emission strongly depends on the…
Warm Absorbers (WAs), as an important form of AGN outflows, show absorption in both UV and X-ray band. Using XSTAR generated photoionization models, for the first time we present a joint fit to the simultaneous observations of HST/COS and…
We study the properties of warm absorbers in several active galaxies (AGN) and present new candidates, using ROSAT X-ray observations. Several aspects of the characteristics of warm absorbers are discussed, constraints on the density and…
The radiation from the central regions of active galactic nuclei, including that from the accretion disk surrounding the black hole, is likely to peak in the extreme ultraviolet $\sim 13 -100$ eV. However, due to Galactic absorption, we are…
We have studied the thermal instabilities in the context of Active Galactic Nuclei (AGN), addressing the cases of thin and thick (stratified) X-ray illuminated media. For that, we have compared the behaviour of different models in pressure…
We model the observed X-ray spectral continuum shape, ionic column densities, and absorption measure distribution (AMD) of the warm absorber in the Seyfert galaxy NGC 3783. We assume a photo-ionized medium with a uniform total…
(Abridged) Many active galactic nuclei exhibit X-ray features typical of the highly ionized gas called "Warm Absorber" (WA). Such a material appears to be stratified, displaying zones of different density, temperature, and ionization. In…
We analyse the ROSAT PSPC hardness ratio and the 0.5-2 keV to 2-10 keV flux ratio of 65 Active Galactic Nuclei (AGN) for which there are both ROSAT archival observations available and 2-10 keV fluxes, mostly from the HEAO-1 MC-LASS survey.…