相关论文: Minimum X-ray source size for a lamp-post corona i…

Occupying the intermediate-mass regime of the accretion--jet parameter space, radio continuum emission from active galactic nuclei with black hole mass M_BH <~ 10^6 Msun (low-mass AGNs) is a valuable probe to the physics of relativistic…

We apply a reflection-based model to the best available XMM-Newton spectra of X-ray bright UltraLuminous X-ray (ULX) sources (NGC 1313 X-1, NGC 1313 X-2, M 81 X-6, Holmberg IX X-1, NGC 5408 X-1 and Holmberg II X-1). A spectral drop is…

This paper discusses the properties of scattering--dominated active galactic nuclei (AGN). We define these to be AGN for which the direct line-of-sight to the continuum source is obscured by Compton-thick material. The aim is to construct,…

The detection of X-ray narrow spectral features in the 5-7 keV band is becoming increasingly more common in AGN observations, thanks to the capabilities of current X-ray satellites. Such lines, both in emission and in absorption, are mostly…

Data from the first three years of RXTE observations have been systematically analyzed to yield a set of 300 day, 2-10 keV light curves with similarly uniform, ~5 day sampling, for a total of nine Seyfert 1 galaxies. This is the first X-ray…

We discuss a model of an X-ray illuminating source above an accretion disk of a rotating black hole. Within the so called lamp-post scheme we compute the expected (observed) polarization properties of the radiation reaching an observer. We…

We present XMM-Newton observations of a complete sample of five archetypal young radio-loud AGN, also known Gigahertz Peaked Spectrum (GPS) sources. They are among the brightest and best studied GPS/CSO sources in the sky, with radio powers…

We present $NuSTAR$ X-ray observations of the active galactic nucleus (AGN) in NGC 7674. The source shows a flat X-ray spectrum, suggesting that it is obscured by Compton-thick gas columns. Based upon long-term flux dimming, previous work…

A NuSTAR/Swift observation of the luminous Seyfert 1 galaxy 1H 0419-577 taken during 2015 reveals one of the most extreme high energy cut-offs observed to date from an AGN - an origin due to thermal Comptonization would imply a remarkably…

We study the X-ray properties of LINER sources with definite detection of a broad H(alpha) emission line in their optical spectra, LINER 1s from Ho et al. sample. These objects preferentially harbor a low luminosity active nucleus at the…

Estimation of the black hole mass in bright X-ray sources of nearby galaxies is crucial to the understanding of these systems and their formation. However, the present allowed black hole mass range spans five order of magnitude (10Msun < M…

A common idea for the origin of the Galactic diffuse X-ray emission, particularly that of the iron lines from neutral and highly ionized atoms, is a superposition of many cataclysmic variables and coronally active binaries. In this…

X-ray spectral lines at unforeseen energies are important because they can shed light on the extreme physical conditions of the environment around the supermassive black holes of active galactic nuclei (AGN). Mrk 876 displays such a line at…

We have newly identified a substantial number of type 1 active galactic nuclei (AGN) featuring weak broad-line regions (BLRs) at z < 0.2 from detailed analysis of galaxy spectra in the Sloan Digital Sky Survey Data Release 7. These objects…

VLT J- to M\p-band adaptive optics observations of the Circinus Galaxy on parsec scales resolve a central bright Ks-band source with a FWHM size of 1.9 $\pm$ 0.6 pc. This source is only visible at wavelengths longward of 1.6 $\mu$m and…

We summarize recent results on the infrared (IR) nuclear properties of Seyfert galaxies. 100% of all Seyfert 1-1.9$ and ~50% of all Seyfert 2s in the CfA and RSA samples observed with HST/NICMOS show nuclear point sources at 1.6micron. We…

Several AGN and black hole X-ray binaries show a clear very broad iron line which is strong evidence that the black holes are rapidly spinning. Detailed analysis of these objects shows that the emission line is not significantly affected by…

A fraction of Narrow Line Seyfert 1 galaxies (NLS1) are hosted by galaxies that present a disturbed morphology, in some cases hinting for merger processes, that are putative sources of gas replenishment. We have been investigating the…

There is clear observational evidence that some narrow line (type 2) AGN have a hidden broad line region (BLR), and are thus intrinsically broad line (type 1) AGN. Does this AGN unification applies for all type 2 AGN? Indirect arguments…

The 13hr XMM-Newton/Chandra deep survey is the first of two extremely deep XMM-Newton fields observed by the XMM-OM consortium. A 120 ks Chandra mosaic, covering 0.2 square degrees, provides sensitive, confusion-free point source detection…