Related papers: Warm absorbers in Seyfert 1 galaxies
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…
Warm absorbers are an important new tool for investigating the conditions within the central regions of active galaxies. They have been observed in ~50% of the well-studied Seyfert galaxies and have also been detected in quite a number of…
We present detailed evidence for a warm absorber in the Seyfert 1 galaxy MCG--6-30-15 and dispute earlier claims for relativistic O line emission. The HETG spectra show numerous narrow, unresolved (FWHM < 200 km/s) absorption lines from a…
We report the detection of ionized absorption in the ASCA spectrum of the narrow-line Seyfert 1 galaxy IRAS 17020+4544. Subsequent optical spectropolarimetry revealed high polarization increasing from 3% in the red to 5% in the blue,…
The Chandra HETGS spectra of the Seyfert 1 galaxy MCG--6-30-15 show numerous narrow, unresolved (FWHM < 200 km/s) absorption lines from a wide range of ionization states of N, O, Mg, Ne, Si, S, Ar, and Fe. The initial analysis of these…
We first provide a review of the properties of warm absorbers concentrating on what we have learned from ROSAT and ASCA. This includes dusty and dust-free warm absorbers, non-X-ray emission and absorption features of warm absorbers, and the…
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…
In about half of Seyfert galaxies, the X-ray emission is absorbed by an optically thin, ionized medium, the so-called "Warm Absorber", whose origin and location is still a matter of debate. The aims of this paper is to put more constraints…
We present a multiwaveband spectroscopic study of the nearby Seyfert 1 galaxy MCG-6-30-15. New optical spectra from the Anglo-Australian Telescope are presented which clearly show the effects of dust extinction/reddening on both the…
Warm absorbers are an important new probe of the central region of active galaxies (AGN). Observing and modeling this component provides a wealth of information on the nature of the warm absorber itself, its relation to other components of…
The variable warm absorber seen with {\em ASCA} in the X-ray spectrum of MCG$-$6-30-15 shows complex time behaviour in which the optical depth of OVIII anticorrelates with the flux whereas that of OVII is unchanging. The explanation in…
There are several Seyfert galaxies for which there is a discrepancy between the small column of neutral hydrogen deduced from X-ray observations and the much greater column derived from the reddening of the optical/UV emission lines and…
We present the results of a 4 day ASCA observation of the Seyfert galaxy MCG-6-30-15, focussing on the nature of the X-ray absorption by the warm absorber, characterizd by the K-edges of the intermediately ionized oxygen, OVII and OVIII. We…
We present a study of the X-ray properties of several NLS1 galaxies, focusing on their warm absorbers. In the first part, we discuss properties of dusty and dust-free warm absorbers in NLS1s, and study their potential contribution to…
We present new XMM-Newton observations of the intriguing warm absorber in I Zwicky 1. This luminous and nearby narrow-line Seyfert 1 galaxy shows ionized absorption by two components of outflowing gas; a low and a high-ionization phase with…
Seyfert galaxies have been shown to exhibit a large variety of features in their X-ray spectra from which the environment of the central engine can be deduced. We focus on the two following aspects: the Warm Absorber, mainly responsible of…
We present analysis and results from the Reflection Grating Spectrometer during the 320 ks XMM observation of the Seyfert 1 galaxy MCG-6-30-15. The spectrum is marked by a sharp drop in flux at 0.7 keV which has been interpreted by…
Signatures of warm absorbers are seen in soft X-ray spectra of about half of all Seyfert1 galaxies observed and in some quasars and blazars. We use the thermal equilibrium curve to study the influence of the shape of the ionizing continuum,…
The absorption lines in the soft X-ray spectrum of MCG--6-30-15 are studied using the Reflection Grating Spectrometer data from the 2001 XMM-Newton 320 ks observation. A line search of the full time-averaged spectrum reveals 51 absorption…
We present a detailed re-analysis of the two {\it ASCA} Performance Verification observations of the nearby Seyfert 1 galaxy MCG-6-30-15. Confirming the results of Fabian et al. (1994), we find definite evidence for the {\sc O\,vii} and…