Related papers: Four new active galaxies with steep soft X-ray spe…

We present an analysis of the X-ray emission of a large sample of z~3 Lyman break galaxies (LBGs), based on Chandra/ACIS observations of several LBG survey fields. 24 LBGs are directly detected in the X-ray. 13 of the LBGs have optical…

We present a sample of 1744 type 1 active galactic nuclei (AGNs) from the Sloan Digital Sky Survey (SDSS DR4) spectroscopic catalog with X-ray counterparts in the White-Giommi-Angelini Catalog (WGACAT) of ROSAT PSPC pointed observations. Of…

Active Galactic Nuclei (AGN) are axisymmetric systems to first order; their observed properties are likely strong functions of inclination with respect to our line of sight, yet the specific inclinations of all but a few AGN are generally…

We present the results of our identification of 14 X-ray sources detected in the eastern Galactic sky ($0<l<180 \circ$ ) in the 4-12 keV energy band on the combined map of the first five all-sky surveys (from December 2019 to March 2022)…

We present the broad-band soft and hard X-ray spectral analysis of 8 Narrow Line Seyfert 1 galaxies extracted from the IBISCO Sample. The study also focuses on the properties of the NLS1 in our sample in relation to those of the IBISCO…

We report the detection of high-amplitude X-ray flaring of the AGN HE 1136-2304, which is accompanied by a strong increase in the flux of the broad Balmer lines, changing its Seyfert type from almost type 2 in 1993 down to 1.5 in 2014. HE…

The Early Data Release of the Sloan Digital Sky Survey (SDSS) contains 150 Narrow-Line Seyfert 1 (NLS1) galaxies, most of them previously unknown. We present here the study of the X-ray emission from two of these active galaxies (SDSS…

Narrow Line Seyfert 1 galaxies represent a distinct category in the larger family of Type 1 Active Galactic Nuclei. The occurrence of emission line profiles not broader than 2000 km/s, combined with luminosity estimates comparable to those…

Active galactic nuclei (AGN) showing dramatic spectral and flux variations, either due to changes in the accretion rate (changing-state, CS-AGN) of the supermassive black hole or in the line-of-sight column density (changing-obscuration,…

We investigate the X-ray variability properties of Seyfert1 Galaxies belonging to the BAT AGN Spectroscopic Survey (BASS). The sample includes 151 unobscured (N$_{\rm H}<10^{22}$ cm$^{-2}$) AGNs observed with XMM-Newton for a total exposure…

We present the results on an XMM-Newton systematic analysis of a sample of nine Seyfert 1 galaxies. When observed in polarised light, the spectra of the selected sources are similar to those of Seyfert 2 galaxies. This peculiarity strongly…

Results obtained from an X-ray spectral survey of nearby Seyfert galaxies using XMM--Newton are reported. The sample was optically selected, well defined, complete in B mag, and distance limited: it consists of the nearest (D<22 Mpc) 27…

Hard X-ray selection is the most efficient way to discriminate between accretion-powered sources, such as AGN, from sources dominated by starlight. Hard X-rays are also less affected than other bands by obscuration. We have then carried out…

ROSAT observations of a homogeneous sample of radio--selected BL Lac objects are presented. Results of a detailed spectral analysis in the soft 0.1-2.0 keV energy range are discussed and compared with similar previously published results.…

Many open questions in X-ray astronomy are limited by the relatively small number of objects in uniform optically-identified samples, especially when rare subclasses are considered, or subsets isolated to search for evolution or…

Zwicky 159.034, one of the Seyfert galaxies identified with EUV sources detected during the ROSAT Wide Field Camera (WFC) all-sky survey, has unusual properties. The ROSAT Position Sensitive Proportional Counter (PSPC) 0.1--2.5 keV X-ray…

High resolution spectroscopic observations of Seyfert galaxies with Chandra and XMM-Newton allows us to study the detailed ionization and thermal structures of the X-ray absorbing/emitting material in the circumnuclear environment. The vast…

We report on our ongoing project of finding Active Galactic Nuclei (AGN) that go into deep X-ray flux states detected by Swift. Swift is performing an extensive study on the flux and spectral variability of AGN using Guest Investigator and…

Based on photoionization calculations we present a study of the NLR emission line ratios of Narrow-line Seyfert 1 (NLS1) galaxies. In particular, we investigate the influence of different EUV - soft-X-ray spectral shapes (a giant soft…

In this paper we investigate the properties of low X-ray-to-optical flux ratio sources detected in a wide area (2.5deg^2) shallow (f(0.5-8keV)~10e-14cgs) XMM-Newton survey. We find a total of 26 sources (5% of the total X-ray selected…