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Related papers: AGN emission processes of NGC 4945 in the X-rays a…

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We utilize the complimentary capabilities of XMM-Newton and Chandra, to conduct a detailed imaging and spectral study of the nearby galaxy NGC 4945 focussing on its nucleus and immediate surroundings (within ~1 kpc of the nucleus). A…

Astrophysics · Physics 2016-08-30 N. J. Schurch , T. P. Roberts , R. S. Warwick

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…

We report hints for the correlation between the X-ray and gamma-ray emission in the nearby galaxy NGC 4945, which harbors both an active galactic nucleus and a nuclear starburst region. We have divided the Fermi/LAT observations of NGC 4945…

High Energy Astrophysical Phenomena · Physics 2017-11-15 Rafal Wojaczynski , Andrzej Niedzwiecki

We present the results of a BeppoSAX observation of the nearby spiral galaxy NGC4945 in the 0.1-200 keV energy band. The nuclear X-ray emission emerges above ~7 keV, through an absorber with column density N_H ~ a few 10^24/cm/cm. Its…

Astrophysics · Physics 2009-09-25 M. Guainazzi , G. Matt , W. N. Brandt , L. A. Antonelli , P. Barr , L. Bassani

Observations of the Seyfert 2 and starburst galaxy NGC 5135 with the Chandra X-ray Observatory demonstrate that both of these phenomena contribute significantly to its X-ray emission. We spatially isolate the active galactic nucleus (AGN)…

Astrophysics · Physics 2016-08-30 N. A. Levenson , K. A. Weaver , T. M. Heckman , H. Awaki , Y. Terashima

Adopting the hypothesis that the nonthermal emission of Active Galactic Nuclei (AGN) is primarily due to the acceleration of protons, we construct a simple model in which the interplay of acceleration and losses can be studied together with…

Astrophysics · Physics 2008-02-03 A. Mastichiadis J. G. Kirk

The Fermi/LAT collaboration recently reported the detection of starburt galaxies in the high energy gamma-ray domain, as well as radio-loud narrow-line Seyfert 1 objects. Motivated by the presence of sources close to the location of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Jean-Philippe Lenain , Claudio Ricci , Marc Türler , Daniela Dorner , Roland Walter

We present a broadband X-ray analysis of a new homogeneous sample of 95 active galactic nuclei (AGN) from the 22-month Swift/BAT all-sky survey. For this sample we treated jointly the X-ray spectra observed by XMM-Newton and INTEGRAL…

High Energy Astrophysical Phenomena · Physics 2015-11-20 A. A. Vasylenko , V. I. Zhdanov , E. V. Fedorova

We present results from a joint Xmm-Newton/NuSTAR monitoring of the Seyfert 1 NGC 4593, consisting of 5x20 ks simultaneous observations spaced by two days, performed in January 2015. The source is variable, both in flux and spectral shape,…

High Energy Astrophysical Phenomena · Physics 2016-08-17 F. Ursini , P. -O. Petrucci , G. Matt , S. Bianchi , M. Cappi , B. De Marco , A. De Rosa , J. Malzac , A. Marinucci , G. Ponti , A. Tortosa

Observations of the Seyfert 2 and starburst galaxy NGC 7130 with the Chandra X-ray Observatory illustrate that both of these phenomena contribute significantly to the galaxy's detectable X-ray emission. The active galactic nucleus (AGN) is…

Astrophysics · Physics 2014-10-13 N. A. Levenson , K. A. Weaver , T. M. Heckman , H. Awaki , Y. Terashima

It is widely believed that the primary X-ray emission of AGN is due to the Comptonisation of optical-UV photons from a hot electron corona, while the origin of the 'soft-excess' is still uncertain and matter of debate. A second…

High Energy Astrophysical Phenomena · Physics 2018-12-19 R. Middei , S. Bianchi , P. -O. Petrucci , F. Ursini , M. Cappi , B. De Marco , A. De Rosa , J. Malzac , A. Marinucci , G. Matt , G. Ponti , A. Tortosa

We check how the Fermi/LAT data constrain physics of hot accretion flows, most likely present in low-luminosity AGNs. Using a precise model of emission from hot flows, we examine the dependence of their gamma-ray emission, resulting from…

High Energy Astrophysical Phenomena · Physics 2015-11-18 Rafal Wojaczynski , Andrzej Niedzwiecki , Fu-Guo Xie , Michal Szanecki

The near-infrared spectra of Active Galactic Nuclei (AGN) present emission lines of different atomic and molecular species. The mechanisms involved in the origin of these emission lines in AGN are still not fully understood. We use J and K…

We present results on approximately one year of INTEGRAL observations of six AGN detected during the regular scans of the Galactic Plane. The sample is composed by five Seyfert 2 objects (MCG -05-23-16, NGC 4945, the Circinus galaxy, NGC…

A wide-frequency radio study of Active Galactic Nuclei (AGN) is crucial to evaluate the intervening radiative mechanisms responsible for the observed emission and relate them with the underlying accretion physics. We present wide frequency…

Astrophysical models for the high-energy emission of blazars are reviewed. Blazars ejecting relativistic radio jets at small angles to the line-of-sight are the only type of active galactic nuclei (AGN) discovered above 100 MeV. The…

Astrophysics · Physics 2007-05-23 Karl Mannheim

NGC 4945 harbors one of the nearest active galactic nuclei (AGN), which allows reaching high spatial resolution with the current observational facilities. The Seyfert 2 nucleus is deeply obscured by an edge-on disk with $A_V\sim14$,…

We present first INTEGRAL and XMM-Newton observations of a Seyfert galaxy, the type 2 AGN NGC 4388. Several INTEGRAL observations performed in 2003 allow us to study the spectrum in the 20 - 300 keV range. In addition two XMM-Newton…

In this letter we present the primary continuum parameters, the photon index Gamma and the high energy cut-off Ec, of 41 type-1 Seyfert galaxies extracted from the INTEGRAL complete sample of AGN. We performed a broad band (0.3-100 keV)…

High Energy Astrophysical Phenomena · Physics 2015-06-18 A. Malizia , M. Molina , L. Bassani , J. B. Stephen , A. Bazzano , P. Ubertini , A. J. Bird

We present new HST NICMOS observations of NGC 4945, a starburst galaxy hosting a highly obscured active nucleus that is one of the brightest extragalactic sources at 100 keV. The HST data are complemented with ground based [FeII] line and…

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