Related papers: Suzaku Confirms NGC~3660 is an Unabsorbed Seyfert …

Obscuration of the continuum emission from active galactic nuclei by streams of gas with relatively high velocity (> 1000 km/s) and column density (>3E25 per m2) has been seen in a few Seyfert galaxies. This obscuration has a transient…

A new BeppoSAX broad-band (0.6-150 keV) spectrum of the Seyfert 2 galaxy Mkn 3 is presented. The spectrum provides a direct measurement of a large, neutral column of gas with Nh~10**24 cm**-2 in the source direction. The source, as bright…

We report on the unveiling of the nature of the unidentified X-ray source 3XMM J005450.3-373849 as a Seyfert-2 galaxy located behind the spiral galaxy NGC 300 using Hubble Space Telescope data, new spectroscopic Gemini observations and…

Suzaku observed a nearby Seyfert 2 galaxy NGC4945, which hosts one of the brightest active galactic nuclei above 20 keV. Combining data from the X-ray CCD camera (XIS) and the Hard X-ray Detector (HXD), the AGN intrinsic nuclear emission…

The type I Seyfert galaxy NGC 3227 was observed by Suzaku six times in 2008, with intervals of $\sim1$ week and net exposures of $\sim50$ ksec each. Among the six observations, the source varied by nearly an order of magnitude, being…

A sample of X-ray and optically selected narrow emission-line galaxies (769 sources) from the 3XMM catalogue cross-correlated with SDSS (DR9) catalogue has been studied. Narrow-emission line active galactic nuclei (AGN; type-2) have been…

We present an analysis of the time-averaged spectrum of the Seyfert-2 active galaxy NGC 4388, obtained by NICER. The intrinsic strength of the reflection spectrum in NGC 4388, the large collecting area and favorable pass band of NICER, and…

We report the discovery of a high redshift, narrow emission-line galaxy identified in the optical follow-up of deep ROSAT fields. The object has a redshift of z=2.35 and its narrow emission lines together with its high optical and X-ray…

We study the X-ray spectra of a sample of 19 obscured, optically-selected Seyfert galaxies (Sy 1.8, 1.9 and 2) in the local universe ($d \leq 175$~Mpc), drawn from the CfA Seyfert sample. Our analysis is driven by the high sensitivity of…

We report the BeppoSAX detection of a hard X-ray excess in the X-ray spectrum of the classical high-ionization Seyfert 2 galaxy Tol0109-383. The X-ray emission of this source observed below 7 keV is dominated by reflection from both cold…

We present the BeppoSAX broad-band X-ray spectrum of the Seyfert 2 galaxy NGC 3281. The source high-energy spectrum is characterized by the nuclear transmitted component, with an absorbing column density of about 2 10^24 cm^-2, while the…

We have analyzed the two longest (elapsed time > 3 days) BeppoSAX observations of the X-ray brightest Seyfert galaxy, NGC 4151, to search for spectral variability on time-scales from a few tens of ksec to years. We found in both cases…

We report on the first detection above ~10 keV of the archetypal Compton-thick Seyfert 2 galaxy NGC 1068. This detection, obtained with the PDS instrument onboard BeppoSAX in the 20-100 keV range, confirms the hardness of the X--ray…

We report on the analysis of a BeppoSAX observation of IRAS 13197-1627. The complexity of the broad band (0.3-100 keV) spectrum of the source prevents us from selecting from two possible best-fit models, i.e. one based on a partial covering…

An-energy dependent variation of the X-ray emission from the archetypical "Compton-thick'' Seyfert 2 galaxy NGC1068 has been observed between two BeppoSAX observations, performed one year apart. This variation (at the 2.6 sigma level) is…

We present jointly analyzed data from three deep Suzaku observations of NGC 1365. These high signal-to-noise spectra enable us to examine the nature of this variable, obscured AGN in unprecedented detail on timescales ranging from hours to…

Initial results on the iron K-shell line and reflection component in several AGN observed as part of the Suzaku Guaranteed time program are reviewed. This paper discusses a small sample of Compton-thin Seyferts observed to date with Suzaku;…

Two type I X-ray bursts were detected from a position consistent with the transient X-ray source in NGC 6652 with the Wide Field Camera of the BeppoSAX satellite, strongly suggesting that this transient is a neutron star. Our detection…

The Seyfert 1 galaxy NGC4151 is characterized by complex X-ray absorption, well described by a dual absorber, composed of a uniform mildly ionized gas and a cold system that partially covers the central source. However, in one of the 5…

We report the Rossi X-ray Timing Explorer observations of the heavily absorbed Seyfert 2 galaxy NGC 4945, which confirm the large column density of the absorber, corresponding to the optical depth to Thomson scattering of about 2.4. The…