Related papers: Decoupling absorption and continuum variability in…
We present two Rossi Xray Timing Explorer (RXTE) PCA observations of the type~2 Seyfert galaxy NGC 4388 caught in an unusual low X-ray absorption state. The observations were triggered by a detection in the 1.5-3 keV band of the RXTE…
We present X-ray observations of the active galactic nucleus (AGN) in NGC 4785. The source is a local Seyfert 2 which has not been studied so far in much detail. It was recently detected with high significance in the 15-60 keV band in the…
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 detailed, time-resolved analysis of the Fe K band of the Seyfert 1.5 galaxy NGC 3516 observed with XRISM. The 249 ks observation spanning $\sim$310 ks in elapsed time reveals an exceptionally rich and time-variable absorption…
We report on the analysis of a long XMM-Newton EPIC observation in 2001 May of the Narrow Line Seyfert 1 galaxy Mkn 766. The 3-11 keV spectrum exhibits a moderately steep power law continuum, with a broad emission line at ~6.7 keV, probably…
This paper reports on a partially simultaneous observation of the bright Seyfert 1 Galaxy Mrk590, performed by XMM-Newton and Chandra. The long exposure (~100 ks) allows to investigate with great detail the Fe K complex at 6-7 keV and the…
We obtained observations of NGC 4639 with ASCA in order to investigate its mildly active Seyfert 1 nucleus at hard X-ray energies. Koratkar et al. (1995) have previously shown that the nucleus is a pointlike source in the ROSAT soft X-ray…
(abridged) The high-resolution X-ray spectrum of NGC 3783 shows several dozen absorption lines and a few emission lines from the H-like and He-like ions of O, Ne, Mg, Si, and S as well as from Fe XVII - Fe XXIII L-shell transitions. We have…
The Seyfert-1 galaxy NGC 3516 has undergone major spectral changes in recent years. In 2017 we obtained Chandra, NuSTAR, and Swift observations during its new low-flux state. Using these observations we model the spectral energy…
We present Chandra and XMM-Newton observations of a small sample (11 objects) of optically-selected Seyfert~2 galaxies, for which ASCA and BeppoSAX had suggested Compton-thick obscuration of the Active Nucleus (AGN). The main goal of this…
This paper presents a BeppoSAX observation of NGC 7582 made during 1998 November and an optical spectrum taken in 1998 October. The new X-ray data reveal a previously unknown hard X-ray component in NGC 7582, peaking close to 20 keV. Rapid…
We study the absorption and emission properties of the photoionised gas near one of the brightest and most variable AGN, the Seyfert galaxy NGC 4051, in order to constrain the geometry, dynamics and ionisation structure of the outflow. We…
We report sub-arcsecond resolution X-ray imaging spectroscopy of the low luminosity active galactic nucleus of NGC 4258 and its immediate surroundings with the Chandra X-ray Observatory. NGC 4258 was observed four times, with the first two…
We present the first high-resolution near-infrared spectroscopy of the nucleus of the nearby, well-known Seyfert galaxy NGC 4151 (the "Eye of Sauron"). Past studies of this source have revealed that it exhibits a variable absorption feature…
Using self-consistent, physically motivated models, we investigate the X-ray obscuration in 19 Type 2 [OIII] 5007 \AA\ selected AGN, 9 of which are local Seyfert 2 galaxies and 10 of which are Type 2 quasar candidates. We derive reliable…
We conduct X-ray reverberation mapping and spectral analysis of the radio galaxy Centaurus A to uncover its central structure. We compare the light curve of the hard X-ray continuum from Swift Burst Alert Telescope observations with that of…
We report on two Chandra observations, and a simultaneous Hubble Space Telescope ultraviolet observation, of the dwarf Seyfert 1 galaxy NGC 4395. Each Chandra observation had a duration of ~30 ks, with a separation of ~50 ks. The spectrum…
There is growing evidence for the presence of blueshifted Fe K absorption lines in a number of radio-quiet AGNs and QSOs. These may be fundamental to probe flow dynamics near supermassive black holes. Here we aim at verifying and better…
The Seyfert 2 galaxy NGC 7674 has been observed within the BeppoSAX Core Programme with the onboard narrow field instruments between 0.1 and 100 keV. The broad-band spectrum shows four most relevant spectral components: a) a soft excess…
We present for the first time a high-resolution X-ray spectrum of a Seyfert galaxy. The Chandra-LETGS spectrum of NGC 5548 shows strong, narrow absorption lines from highly ionised species (the H-like and He-like ions of C, N, O, Ne, Na,…