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X-ray spectroscopy of active galactic nuclei (AGN) offers the opportunity to directly probe the inner regions of the accretion disk. We present the results of our analysis of average AGN XMM-Newton X-ray spectra in the Chandra Deep Field…

High Energy Astrophysical Phenomena · Physics 2014-08-12 S. Falocco , F. J. Carrera , A. Corral , X. Barcons , A. Comastri , R. Gilli , P. Ranalli , C. Vignali , K. Iwasawa , N. Cappelluti , E. Rovilos , I. Georgantopoulos , M. Brusa , F. Vito

Compton Thick (CT) AGN are a key ingredient of Cosmic X-ray Background (CXB) synthesis models, but are still an elusive component of the AGN population beyond the local Universe. Multi-wavelength surveys are the only way to find them at z >…

Astrophysics of Galaxies · Physics 2017-05-10 G. Lanzuisi

We present results of recurrence analysis of 46 active galactic nuclei (AGN) using light curves from the 157-month catalog of the Swift Burst Alert Telescope (BAT) in the 14-150 keV band. We generate recurrence plots and compute recurrence…

High Energy Astrophysical Phenomena · Physics 2022-11-28 R. A. Phillipson , M. S. Vogeley , P. T. Boyd

We present a detailed analysis of the most luminous and obscured Active Galactic Nuclei (AGNs) detected in the ultra-hard X-ray band (14-195 keV) by Swift/BAT. Our sample comprises 21 X-ray luminous (log $L_X/{\rm erg\,s^{-1}}>44.6$, 2-10…

We perform a detailed investigation of moderate-to-high quality X-ray spectra of ten of the most luminous active galactic nuclei (AGNs) known at z>4 (up to z~6.28). This study includes five new XMM observations and five archived X-ray…

Astrophysics · Physics 2008-11-26 O. Shemmer , W. N. Brandt , C. Vignali , D. P. Schneider , X. Fan , G. T. Richards , M. A. Strauss

We present a comprehensive analysis of the X-ray spectral properties of 198 newly identified active galactic nuclei (AGNs), leveraging archival data from the {\it Chandra} X-ray Observatory. All these AGNs exhibit a powerlaw spectral…

High Energy Astrophysical Phenomena · Physics 2024-10-08 Samrat Ghosh , Samir Mandal , Sudip Bhattacharyya , Shivam Kumaran

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,…

Astrophysics · Physics 2009-10-30 H. Netzer , T. J. Turner , I. M. George

We develop a physically motivated, spherical corona model to investigate the frequency-dependent time lags in AGN. The model includes the effects of Compton up-scattering between the disc UV photons and coronal electrons, and the subsequent…

High Energy Astrophysical Phenomena · Physics 2022-08-31 P. Chainakun , A. Watcharangkool , A. J. Young , S. Hancock

The origin of core radio emission in radio-quiet active galactic nuclei (AGNs) is still actively debated. General relativistic magnetohydrodynamics simulations often predict the launching of moderately large-scale jets from super-Eddington…

High Energy Astrophysical Phenomena · Physics 2026-01-13 Jeremiah D. Paul , Richard M. Plotkin

The variation in the high energy cut-off E_c in active galactic nuclei uniquely probes the corona physics. In this work we show that the ratio of two NuSTAR spectra (in analogy to difference imaging technique widely used in astronomy) is…

High Energy Astrophysical Phenomena · Physics 2018-08-15 Ji-Xian Zhang , Jun-Xian Wang , Fei-Fan Zhu

We aim to measure the physical properties of the hot X-ray corona of two active galactic nuclei, NGC 4388 and NGC 2110. We analysed the hard X-ray (20-300 keV) INTEGRAL spectrum in conjunction with archival XMM-Newton and NuSTAR data. The…

High Energy Astrophysical Phenomena · Physics 2019-09-04 F. Ursini , L. Bassani , A. Malizia , A. Bazzano , A. J. Bird , J. B. Stephen , P. Ubertini

We present measurement of the cut-off energy, a proxy for the temperature of the corona in the nuclear continuum of the Seyfert 1 galaxy 3C 120 using $\sim$120 ks of observation from ${\it NuSTAR}$. The quality broad band spectrum from…

High Energy Astrophysical Phenomena · Physics 2018-04-11 Priyanka Rani , C. S. Stalin

We present a systematical analysis of the Chandra observations of 53 nearby highly-inclined (i>60 degree) disk galaxies to study the coronae around them. This sample covers a broad range of galaxy properties: e.g., about three orders of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Jiang-Tao Li , Q. Daniel Wang

Context. AGNs are strong X-ray emitters shaped by disk-corona interactions. The soft excess (0.5-2.0 keV) reveals key information about the "warm corona" bridging the disk and hot corona. Yet, how this feature evolves with accretion…

We combine the Herschel Space Observatory PACS and SPIRE photometry with archival WISE photometry to construct the spectral energy distributions (SED) for over 300 local ($z < 0.05$), ultra-hard X-ray (14 - 195 keV) selected active galactic…

Astrophysics of Galaxies · Physics 2017-02-01 T. Taro Shimizu , Richard F. Mushotzky , Marcio Meléndez , Michael J. Koss , Amy J. Barger , Lennox L. Cowie

The supermassive black holes ($M_{\rm BH} \sim 10^{6}$$-$$10^{10}~M_\odot$) that power luminous active galactic nuclei (AGNs), i.e., quasars, generally show a correlation between thermal disk emission in the ultraviolet (UV) and coronal…

We perform the NuSTAR and Swift/XRT joint energy spectral fitting of simultaneous observations from the broad-line Seyfert 1.5 galaxy NGC 5273. When fitted with the combination of an exponential cut-off power-law and a reflection model, a…

High Energy Astrophysical Phenomena · Physics 2017-07-26 Mayukh Pahari , I. M. McHardy , Labani Mallick , G. C. Dewangan , R. Misra

This White Paper explores advances in the study of Active Galaxies which will be enabled by new observing capabilities at MeV energies (hard X-rays to gamma-rays; 0.1-1000 MeV), with a focus on multi-wavelength synergies. This spectral…

Recent detection of very-high-energy neutrino emission from Seyfert type active galactic nuclei (AGN) provides a new insight into the physics of the AGN central engines. We notice that if high-energy protons responsible for neutrino…

High Energy Astrophysical Phenomena · Physics 2025-07-01 A. Neronov , O. Kalashev , D. V. Semikoz , D. Savchenko , M. Poleshchuk

We report on the first observation of a radio-quiet Active Galactic Nucleus (AGN) using polarized X-rays: the Seyfert 1.9 galaxy MCG-05-23-16. This source was pointed with the Imaging X-ray Polarimetry Explorer (IXPE) starting on May 14,…