Related papers: Warm Absorbers in Active Galactic Nuclei
We present results from a 50 ks observation of the narrow-line Seyfert 1 galaxy Ark 564 with the Chandra HETGS. The spectra above 2 keV are modeled by a power-law with a photon-index of 2.56+/-0.06. We confirm the presence of the soft…
The inhomogeneous cooling flow scenario predicts the existence of large quantities of gas in massive elliptical galaxies, groups, and clusters that have cooled and dropped out of the flow. Using spatially resolved, deprojected X-ray spectra…
The excellent soft X-ray sensitivity of the PSPC detector onboard the ROSAT satellite provided the first chance to study precisely the spectral and timing properties of Narrow-Line Seyfert 1 galaxies. ROSAT observations of Narrow-Line…
We present the first detailed X-ray analysis of three AGN, the Seyfert 1 galaxies UGC 3142 and ESO 140-43, and the Seyfert 2 galaxy ESO 383-18, in order to study the geometry and the physical characteristics of their absorbers. High quality…
Detection of absorbed active galactic nuclei and their properties remains an elusive and important problem in understanding the evolution and activation of black holes. With the very hard X-ray survey conducted by Swift's Burst Alert…
We present an analysis of our Chandra Low Energy Transmission Grating Spectrometer (LETGS) observation of the quasar MR2251-178. The warm absorber of MR2251-178 is well described by a hydrogen column density, N_H~2x10^21 cm^-2, and an…
We present results from an analysis of the broad-band, 0.3-195 keV, X-ray spectra of 48 Seyfert 1-1.5 sources detected in the very hard X-rays with the Swift Burst Alert Telescope (BAT). This sample is selected in an all-sky survey…
The first systematic study of the warm gas (T=10^4-5 K) distribution across a galaxy cluster is presented using multiple background QSOs to the Virgo Cluster. We detect 25 Lya absorbers (N_HI = 10^13.1-15.4 cm^-2) in the Virgo velocity…
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…
(Abridged) NGC 985 was observed by XMM-Newton twice in 2015, revealing that the source was coming out from a soft X-ray obscuration event that took place in 2013. These kinds of events are possibly recurrent since a previous XMM-Newton…
We present the analysis and results from a series of XMM-Newton observations of the distant blazar PMN J0525-3343, at a redshift of 4.4. The X-ray spectrum shows a spectral flattening below ~1 keV confirming earlier results from ASCA and…
The analysis of X-ray absorption features in active galactic nuclei (AGN) provides a wealth of information about the physical properties of the matter surrounding supermassive black holes (SMBHs). While standard correlations between the…
The emission and absorption attributes of the UV-blue nuclear spectra of the Narrow-Line Seyfert 1 (NLS1) galaxies are analyzed based on high quality archival HST observations. Measurements from composite spectra as well as from individual…
BeppoSAX observations of the high redshift (z=4.72) blazar GB 1428+4217 confirm the presence of a complex soft X-ray spectrum first seen with the ROSAT PSPC. Flattening below a rest frame energy of 5 keV can be accounted for by absorption…
We present XMM-Newton EPIC observations of warm absorbers in the quasars PG 1114+445 and PG 1309+355, both of which exhibit evidence for absorption by warm material in the line-of-sight. We find the absorption in PG 1114+445 to be in two…
We review the soft X-ray properties of 3C 390.3, 3C 120, 3C 382 and 3C 445, the only Broad Line Radio Galaxies (BLRG) for which good quality gratings data are currently available. The XMM-Newton/RGS data of 3C 390.3 and 3C 120 were…
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…
This article focuses on certain variability and emission characteristics of Active Galactic Nuclei (AGN), especially their radio-loud subset consisting of quasars, BL Lacs and $\gamma$-ray detected narrow-line Seyfert 1 galaxies, all of…
While it is possible to explain Lyman alpha absorber counts at low redshift using gas which is associated with moderately extended galaxies (Linder 1997), absorbers are often observed to be associated with galaxies at larger impact…
Context. Ionized outflows in active galactic nuclei (AGNs) are thought to influence the evolution of their host galaxies and super-massive black holes (SMBHs). Distance is important to understand the kinetic power of the outflows as a…