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In the past five years, a flurry of X-ray reverberation lag measurements of accreting supermassive black holes have been made using the XMM-Newton telescope in the 0.3-10 keV energy range. In this work, we use the NuSTAR telescope to extend…
We present a spectral analysis of four coordinated NuSTAR+XMM-Newton observations of the Seyfert galaxy NGC 1365. These exhibit an extreme level of spectral variability, which is primarily due to variable line-of-sight absorption, revealing…
The Seyfert 2 galaxy Mrk 1210 was found to exhibit a flat hard X-ray component by ASCA, although ASCA could not distinguish whether it is an absorbed direct component or a reflected one. We then observed Mrk 1210 with BeppoSAX, and found…
While a broad profile of the Fe K$\alpha$ emission line is frequently found in the X-ray spectra of typical Seyfert galaxies, the situation is unclear in the case of Narrow Line Seyfert 1 galaxies (NLS1s)---an extreme subset which are…
We present Chandra ACIS-S imaging spectroscopy results of the extended (1.5''- 8'', 300 pc-1600 pc) hard X-ray emission of NGC 5728, the host galaxy of a Compton thick active galactic nucleus (CT AGN). We find spectrally and…
We report on one of the brightest flux levels of the Seyfert 2 galaxy NGC 2992 ever observed in X-rays, on May 2019. The source has been monitored every few days from March 26, 2019 to December 14, 2019 by Swift-XRT, and simultaneous…
Archival XMM-Newton data on the nearby Seyfert galaxy NGC 4051, taken in relatively high and low flux states, offer a unique opportunity to explore the complexity of its X-ray spectrum. We find the hard X-ray band to be significantly…
We report on the results of 18 observations of the core, or peak, of the Fe K emission line at $\sim 6.4$ keV in 15 Seyfert I galaxies using the {\it Chandra} High Energy Grating (HEG). These data afford the highest precision measurements…
The recent detection of X-ray reverberation lags, especially in the Fe K\alpha\ line region, around Active Galactic Nuclei (AGN) has opened up the possibility of studying the time-resolved response (reflection) of hard X-rays from the…
We present a broadband X-ray analysis of a new homogeneous sample of 95 active galactic nuclei (AGN) from the 22-month Swift/BAT all-sky survey. For this sample we treated jointly the X-ray spectra observed by XMM-Newton and INTEGRAL…
We present an analysis of the X-ray spectra of a sample of 37 observations of 26 Seyfert galaxies observed by XMM-Newton in order to characterize their iron K emission. All objects show evidence for iron line emission in the 6-7 keV band. A…
We have studied the average 3-200 keV spectra of Seyfert galaxies of type 1 and 2, using data obtained with BeppoSAX. The average Seyfert 1 spectrum is well-fitted by a power law continuum with photon spectral index Gamma~1.9, a Compton…
We present results of a 100 ks XMM observation of the Seyfert 1.5 NGC 3227. Our best-fit broadband model to the pn spectrum consists of a moderately flat (photon index 1.57) hard X-ray power-law absorbed by cold gas with N_H = 3 * 10^21…
We review observations and theoretical models of X-ray/gamma-ray spectra of radio-quiet Seyfert galaxies and of Galactic black-hole candidates (in the hard spectral state). The observed spectra share all their basic components: an…
X-ray unabsorbed Seyfert 2 galaxies appear to have X-ray absorption column densities that are too low (NH < 10^22 cm-2) to explain the absence of broad emission lines in their optical spectra, challenging the standard AGN unification model.…
An extended XMM-Newton observation of the Seyfert 1 galaxy NGC 4051 in 2009 detected a photo-ionized outflow with a complex absorption line velocity structure and a broad correlation of velocity with ionization parameter, shown in Pounds et…
We present the first NuSTAR observation of a 'true' Type 2 Seyfert galaxy. The 3-40 keV X-ray spectrum of NGC3147 is characterised by a simple power-law, with a standard {\Gamma}~1.7 and an iron emission line, with no need for any further…
In this paper we report on the broadband X-ray properties of a complete sample of 33 absorbed Seyfert galaxies hard X-ray selected with integral. The high quality broadband spectra obtained with both xmm, and integral-IBIS data are well…
Recent work by Risaliti et al.(1999) suggests that more than half of all Seyfert 2 galaxies in the local universe are Compton-thick (N_H > 10^24 cm^-2). This has implications for AGN synthesis models for the X-ray background (XRB), the…
This paper reports on the first results of the Suzaku observation in the Sgr C region. We detected four diffuse clumps with strong line emission at 6.4keV, Ka from neutral or low-ionized Fe. One of them, M359.38-0.00, is newly discovered…