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The observed nuclear X-ray emission in the radio-quiet category of active galactic nuclei (AGN) is believed to be from a compact region, the corona situated in the vicinity of the central supermassive black holes (SMBH). The shape of the…

High Energy Astrophysical Phenomena · Physics 2022-06-22 Indrani Pal , C. S. Stalin , L. Mallick , Priyanka Rani

We present systematic and uniform analysis of NuSTAR data with 10-78 keV S/N > 50, of a sample of 60 SWIFT BAT selected AGNs, 10 of which are radio-loud. We measure their high energy cutoff Ecut or coronal temperature Te using three…

High Energy Astrophysical Phenomena · Physics 2022-04-27 Jia-Lai Kang , Jun-Xian Wang

Investigating how the cutoff energy $E_{\rm cut}$ varies with X-ray flux and photon index $\Gamma$ in individual AGNs opens a new window to probe the yet unclear coronal physics. So far $E_{\rm cut}$ variations have only been detected in…

High Energy Astrophysical Phenomena · Physics 2021-01-13 Jia-Lai Kang , Jun-Xian Wang , Wen-Yong Kang

While the temperature of the X-ray corona ($\rm{kT_e}$) in active galactic nuclei (AGN) are known for many sources, its variation, if any, is limited to a handful of objects. This is in part due to the requirement of good signal-to-noise…

High Energy Astrophysical Phenomena · Physics 2022-11-30 Indrani Pal , C. S. Stalin

NuSTAR observatory, with its 3 - 78 keV broadband spectral coverage, enables the detections of the high-energy cutoff in a number of active galaxies, including several individual radio loud ones. In this work we present systematic and…

High Energy Astrophysical Phenomena · Physics 2020-09-29 Jia-lai Kang , Jun-xian Wang , Wen-yong Kang

Measurements of the high-energy cut-off in the coronal continuum of active galactic nuclei have long been elusive for all but a small number of the brightest examples. We present a direct measurement of the cut-off energy in the nuclear…

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

We carried out a uniform and systematic analysis of a sample of 112 nearby bright Seyfert 1 type AGN, the observations of which were carried out by the Nuclear Spectroscopic Telescope Array (NuSTAR) between August 2013 and May 2022. The…

High Energy Astrophysical Phenomena · Physics 2024-10-22 Indrani Pal , Anju A. , H. Sreehari , Gitika Rameshan , C. S. Stalin , Claudio Ricci , Stefano Marchesi

The primary X-ray emission in active galactic nuclei (AGN) originates in a compact region called the corona located very close to the super-massive black hole and the accretion disk. The knowledge of the cut-off energy ($E_{cut}$) of the…

High Energy Astrophysical Phenomena · Physics 2019-01-30 Priyanka Rani , C. S. Stalin , K. D. Goswami

We report flux-resolved spectroscopic analysis of the active galactic nucleus (AGN) ESO 103--035 using \textit{NuSTAR} observations. Following an earlier work, we fit the spectra using a thermal Comptonization model with a relativistic…

High Energy Astrophysical Phenomena · Physics 2021-11-02 Samuzal Barua , V. Jithesh , Ranjeev Misra , Gulab C Dewangan , Rathin Sarma , Amit Pathak , Biman J Medhi

We present the 0.5 - 78 keV spectral analysis of 18 broad line AGN belonging to the INTEGRAL complete sample. Using simultaneous Swift-XRT and NuSTAR observations and employing a simple phenomenological model to fit the data, we measure…

High Energy Astrophysical Phenomena · Physics 2019-01-23 Manuela Molina , Angela Malizia , Loredana Bassani , Francesco Ursini , Angela Bazzano , Pietro Ubertini

Broadband X-ray spectroscopy of the X-ray emission produced in the coronae of active galactic nuclei (AGN) can provide important insights into the physical conditions very close to their central supermassive black holes. The temperature of…

Recent intensive monitoring campaigns of active galactic nuclei (AGN) have provided simultaneous X-ray, UV, and optical data of unprecedented quality. The observations reveal a strong correlation between the UV and optical variability, but…

High Energy Astrophysical Phenomena · Physics 2026-01-28 M. Papoutsis , I. E. Papadakis , C. Panagiotou , E. Kammoun , M. Dovciak

The NuSTAR observatory, with its high sensitivity in hard X-rays, has enabled detailed broadband modeling of the X-ray spectra of Active Galactic Nuclei (AGN), thereby allowing constraints to be placed on the high-energy cutoff of the X-ray…

High Energy Astrophysical Phenomena · Physics 2018-11-14 Nikita Kamraj , Fiona Harrison , Mislav Baloković , Anne Lohfink , Murray Brightman

We present results from a 244\,ks \textit{NuSTAR} observation of 3C\,273 obtained during a cross-calibration campaign with the \textit{Chandra}, \textit{INTEGRAL}, \textit{Suzaku}, \textit{Swift}, and \textit{XMM-Newton} observatories. We…

Active galactic nuclei (AGN) are extremely variable in the X-ray band down to very short timescales. However, the driver behind the X-ray variability is still poorly understood. Previous results suggest that the hot corona responsible for…

MCG-5-23-16 was targeted in early 2015 with a half mega-seconds observing campaign using NuSTAR. Here we present the spectral analysis of these datasets along with an earlier observation and study the relativistic reflection and the primary…

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

Compact radio AGN are thought to be young radio active galactic nuclei (AGN) at the early stage of AGN evolution, thus are ideal laboratory to study the high-energy emission throughout the evolution of radio AGN. In this work, we report for…

High Energy Astrophysical Phenomena · Physics 2024-01-11 Mai Liao , Junxian Wang , Jialai Kang , Xiaofeng Li , Minhua Zhou

The X-ray emission of active galactic nuclei (AGN) is generally attributed to inverse Compton scattering of accretion-disk photons by hot electrons in a compact corona. In local AGN, directly constraining coronal properties is challenging…

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