Related papers: Minimum X-ray source size for a lamp-post corona i…
We show that disc continuum fitting can be used to constrain black hole spin in a subclass of Narrow Line Seyfert 1 (NLS1) AGN as their low mass and high mass accretion rate means that the disc peaks at energies just below the soft X-ray…
This paper presents the analysis of a statistically complete sample of 28 serendipitous X-ray sources selected in 82 pointed XMM-Newton fields down to a count-rate of 0.002 counts s^-1(4.5-7.5 keV energy band). This is the first sample…
We report the results of an XMM-Newton observation of the Narrow-Line Seyfert 1 galaxy Mkn 1239. This optically highly polarized AGN has one of the steepest X-ray spectra found in AGN with alpha-X = +3.0 based on ROSAT PSPC data. The…
We report the optical identification of the hardest X-ray source (AX J131501+3141) detected in an unbiased wide-area survey in the 0.5--10 keV band, the ASCA Large Sky Survey. The X-ray spectrum of the source is very hard and is well…
Hard X-ray emission in radio-quiet active galactic nuclei (AGNs) is believed to be produced via inverse Compton scattering by hot and compact coronae near the super massive black hole. However the origin and physical properties of the…
We have observed with XMM-Newton four radiatively efficient active type 1 galaxies with black hole masses < 10^6 Msun, selected optically from the SDSS. We show here that their soft X-ray spectrum exhibits a soft excess with the same…
We present results from a deep, coordinated $XMM$-$Newton$ + $NuSTAR$ observation of the type 1 Seyfert PG 1426+015, a source of particular interest as the most massive reverberation-mapped black hole to date ($\log [M_{\rm{BH}}/M_{\odot}]$…
We present our statistical study of near infrared (NIR) variability of X-ray selected Active Galactic Nuclei (AGN) in the COSMOS field, using UltraVISTA data. This is the largest sample of AGN light curves in YJHKs bands, making possible to…
We present the results from the spectral and timing analysis of the accreting neutron star 1A~1744-361 from the \nustar{} observation performed in its 2022 outbursts. The unabsorbed bolometric X-ray luminosity during this observation in the…
The fraction of AGN with photoelectric absorption in the X-rays ranging from NH of 10^{22} up to about 10^{24} cm^{-2} (Compton-thin) appears observationally to be anticorrelated to their luminosity Lx. This recently found evidence is used…
The X-ray emitting corona irradiates and ionises the surface of the inner accretion disc in Active Galactic Nuclei (AGNs). The ionisation parameter of the inner disc at a radius $r$ from the black hole, $\xi(r)$, can be used to infer…
Narrow-line Seyfert 1 (NLS1) galaxies are a class of active galactic nuclei (AGN) that, in some cases, can harbor powerful relativistic jets. One of them, PKS 2004-447, shows gamma-ray emission, and underwent its first recorded…
We present the X-ray spectra of 86 optically-identified sources in the 13H XMM-Newton/Chandra deep field which have >70 X-ray counts. The sample consists of 50 broad line AGN, 25 narrow emission line galaxies, 6 absorption line galaxies,…
[Abridged]We report on the broadband X-ray properties of a complete sample of absorbed Seyfert galaxies hard X-ray selected with INTEGRAL. The sample is composed of 33 sources: 15 are newly discovered above 20 keV while 18 are already known…
Rebirth of X-ray polarimetric instruments will have a significant impact on our knowledge of compact accreting sources. The properties of inner-accreting regions of active galactic nuclei (AGNs) or X-ray binary systems (XRBs), such as…
Based on a deep survey of the Galactic Center region performed with the INTEGRAL observatory, we measured for the first time the hard X-ray (20-200 keV) spectrum of the Seyfert 1 galaxy GRS 1734-292 located in the direction of the Galactic…
The spectrum and light curve of the bright X-ray source CG X-1 in the field of the Circinus galaxy are re-examined. Previous analyses have concluded that the source is an accreting black hole of about 50 solar masses although it was noted…
We have combined Hubble Space Telescope/Faint Object Spectrograph, ground-based, and Infrared Space Observatory spectra of the nucleus of NGC 4395, the least luminous and nearest known type 1 Seyfert galaxy. The spectra show emission lines…
Narrow Line Seyfert 1 (NLSy1) galaxies are a peculiar class of type 1 AGN (BLSy1). The X-ray properties of individual objects belonging to this class are often extreme and associated with accretion at high Eddington ratios. Here we present…
The contribution of the iron emission line, commonly detected in the X-ray spectra of Seyfert (Sey) galaxies, to the cosmic X-ray background (XRB) spectrum is evaluated in the framework of the XRB synthesis models based on AGN unification…