相关论文: The Hard X-ray Emission of Cen A

We revisit the average hard X-ray spectrum from the AGN of Centaurus A (Cen A) using ten years worth of observations with INTEGRAL SPI. This source has the highest flux observed from any AGN in the SPI bandpass (23 keV--8 MeV). The 10 year…

We report on an analysis of \fermi data from four year of observations of the nearby radio galaxy Centaurus A (Cen A). The increased photon statistics results in a detection of high-energy ($>\:100$ MeV) $\gamma$-rays up to 50 GeV from the…

We study the contribution of thermal and non-thermal processes to the inverse Compton emission of the radio galaxy M 87 by modelling its broad-band emission. Through this we aim to derive insight into where within the AGN the X-ray,…

The question of the origin of the hard X-ray/soft gamma-ray emission in Centaurus A (Cen A) persists despite decades of observations. Results from X-ray instruments suggest a jet origin since the implied electron temperature (kT_e) would…

We have obtained measurements and upper limits on the emission of Cyg X-1 in the photon energy range of 0.03--300 GeV based on observations by Fermi. We present the results separately for the hard and soft spectral states, as well for all…

We have obtained a firm detection of Cyg X-1 during its hard and intermediate spectral states in the energy range of 40 MeV--60 GeV based on observations by the Fermi Large Area Telescope, confirming the independent results at $\geq$60MeV…

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…

We study a broad-band X-ray observation by BeppoSAX of the broad-line radio galaxy 3C 120. The primary X-ray continuum is well described by a power law with the photon index of Gamma=1.85+-0.05 and a high-energy break or a cutoff. The…

Context : If relativistic particle acceleration takes place in colliding-wind binaries, hard X-rays and gamma-rays are expected through inverse Compton emission, but to date these have never been unambiguously detected. Aims : To detect…

Hard X-ray spectra of 28 bright Seyfert galaxies observed with INTEGRAL were analyzed together with the X-ray spectra from XMM-Newton, Suzaku and RXTE. These broad-band data were fitted with a model assuming a thermal Comptonization as a…

Detection of hard X-ray spectrum (spectral index < 2) from the kilo-parsec scale jet of active galactic nuclei cannot be accounted to the synchrotron emission mechanism from the electron distribution responsible for the radio/optical…

Centaurus A, the closest active galaxy, has been detected from radio to high-energy gamma-rays. The synchrotron radiation by extremely high energy protons may be a suitable mechanism to explain the MeV to GeV emission detected by the…

We present simultaneous XMM-Newton and NuSTAR observations spanning 3-78 keV of the nearest radio galaxy, Centaurus A (Cen A). The accretion geometry around the central engine in Cen A is still debated, and we investigate possible…

Centaurus A, at a distance of less than 4 Mpc, is the nearest radio-loud AGN. Its emission is detected from radio to very-high energy gamma-rays. Despite the fact that Cen A is one of the best studied extragalactic objects the origin of its…

Hard, non-thermal, persistent pulsed X-ray emission extending between 10 keV and $\sim 150$ keV has been observed in nearly ten magnetars. For inner-magnetospheric models of such emission, resonant inverse Compton scattering of soft thermal…

The H.E.S.S. experiment has reported the detection of very high energy (VHE: E>100 GeV) gamma-ray emission from the well-known radio-galaxy Cen A. Following this discovery, we refine the previous multi-blob synchrotron self-Compton (SSC)…

The X-ray spectra of many active galactic nuclei (AGN) show a soft X-ray excess below 1-2 keV on top of the extrapolated high- energy power law. The origin of this component is uncertain. It could be a signature of relativistically blurred,…

The results of a spectral analysis, using {\it XMM-Newton} and {\it Chandra} data of the brightest ultra luminous X-ray source in the nearby galaxy M82, are presented. The spectrum of M82 X-1, was found to be unusually hard (photon spectral…

We present the results of spectral analysis of 42 simultaneous broad-band Ginga--OSSE and RXTE--OSSE observations of Cyg X-1 carried out in 1991 and 1996--1999. The hardest spectra in our sample in the energy range from 3 to \~1000 keV can…

The widespread detection of synchrotron X-ray emission from the jets of low-power, nearby radio galaxies implies the presence of electrons at and above TeV energies. In this paper we explore the possibility that the TeV gamma-rays detected…