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X-ray spectra of active galactic nuclei (AGN) consist of several different emission and absorption components, which are often fitted manually with models chosen on a case-by-case basis. However, it becomes very hard for a survey with a…

High Energy Astrophysical Phenomena · Physics 2022-11-23 Lingsong Ge , Stéphane Paltani , Dominique Eckert

We discuss a Bayesian methodology for the solution of the inverse problem underlying the determination of parton distribution functions (PDFs). In our approach, Gaussian Processes (GPs) are used to model the PDF prior, while Bayes theorem…

High Energy Physics - Phenomenology · Physics 2024-07-03 Alessandro Candido , Luigi Del Debbio , Tommaso Giani , Giacomo Petrillo

We present an analysis of the X-ray properties of sources detected in the 13H XMM-Newton deep (200ks) field. In order to constrain the absorbed AGN population, we use extensive Monte Carlo simulations to directly compare the X-ray colours…

Astrophysics · Physics 2009-11-11 T. Dwelly , M. J. Page , N. S. Loaring , K. O. Mason , I. McHardy , K. Gunn , T. Sasseen

We present the most up-to-date X-ray luminosity function (XLF) and absorption function of Active Galactic Nuclei (AGNs) over the redshift range from 0 to 5, utilizing the largest, highly complete sample ever available obtained from surveys…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Yoshihiro Ueda , Masayuki Akiyama , Guenther Hasinger , Takamitsu Miyaji , Michael G. Watson

We have used very deep XMM-Newton observations of the Chandra Deep Field-South to examine the spectral properties of the faint active galactic nucleus (AGN) population. Crucially, redshift measurements are available for 84% (259/309) of the…

Astrophysics · Physics 2009-11-11 T. Dwelly , M. J. Page

Building on the first paper in this series (Duncan et al. 2018), we present a study investigating the performance of Gaussian process photometric redshift (photo-z) estimates for galaxies and active galactic nuclei detected in deep radio…

Astrophysics of Galaxies · Physics 2018-05-24 Kenneth J Duncan , Matt J. Jarvis , Michael J. I. Brown , Huub J. A. Rottgering

A complete census of Active Galactic Nuclei (AGN) is a prerequisite for understanding the growth of supermassive black holes across cosmic time. A significant challenge toward this goal is the whereabouts of heavily obscured AGN that remain…

We present here a detailed X-ray spectral analysis of the AGN belonging to the XMM-Newton bright survey (XBS) that comprises more than 300 AGN up to redshift ~ 2.4. We performed an X-ray analysis following two different approaches: by…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 A. Corral , R. Della Ceca , A. Caccianiga , P. Severgnini , H. Brunner , F. J. Carrera , M. J. Page , A. D. Schwope

Modern cosmological simulations rely heavily on feedback from active galactic nuclei (AGN) in order to stave off overcooling in massive galaxies and galaxy groups and clusters. An important independent test is whether or not the simulations…

Our goal is to probe the populations of obscured and unobscured AGN investigating their optical-IR and X-ray properties as a function of X-ray flux, luminosity and redshift within a hard X-ray selected sample of 136 X-ray sources in the XMM…

The cosmic X-ray background (CXB) is produced by the emission of unresolved active galactic nuclei (AGN), thus providing key information about the properties of the primary and reprocessed X-ray emission components of the AGN population.…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-28 D. Gerolymatou , S. Paltani , C. Ricci , M. Regamey

Intrinsic absorption is a fundamental physical property to understand the evolution of active galactic nuclei (AGN). Here a sample of 1290 AGN, selected in the 2-10 keV band from different flux-limited surveys with very high optical…

Astrophysics · Physics 2009-11-13 G. Hasinger

Numerous X-ray spectral models have been developed to model emission reprocessed by the torus of an active galactic nucleus (AGN), e.g., UXCLUMPY, CTORUS, and MYTORUS. They span a range of assumed torus geometries and morphologies-some…

High Energy Astrophysical Phenomena · Physics 2021-12-15 Tathagata Saha , Alex G. Markowitz , Johannes Buchner

In the past few years, approximate Bayesian Neural Networks (BNNs) have demonstrated the ability to produce statistically consistent posteriors on a wide range of inference problems at unprecedented speed and scale. However, any disconnect…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-24 Sebastian Wagner-Carena , Ji Won Park , Simon Birrer , Philip J. Marshall , Aaron Roodman , Risa H. Wechsler

Among the most extreme objects in the Universe, active galactic nuclei (AGN) are luminous centers of galaxies where a black hole feeds on surrounding matter. The variability patterns of the light emitted by an AGN contain information about…

Instrumentation and Methods for Astrophysics · Physics 2021-06-22 Ji Won Park , Ashley Villar , Yin Li , Yan-Fei Jiang , Shirley Ho , Joshua Yao-Yu Lin , Philip J. Marshall , Aaron Roodman

We studied the Active Galactic Nuclei (AGN) radio emission from a compilation of hard X-ray selected samples, all observed in the 1.4 GHz band. A total of more than 1600 AGN with 2-10 keV de-absorbed luminosities higher than 10^42 erg/s…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 F. La Franca , G. Melini , F. Fiore

The synthesis model for the cosmic X-ray background (XRB) -based on the integrated emission of Active Galactic Nuclei (AGNs)- is complemented with new observational results. We adopt the most recent estimates of the AGN X-ray luminosity…

Astrophysics · Physics 2007-05-23 R. Gilli , G. Risaliti , M. Salvati

X-ray surveys of active galactic nuclei (AGNs) provide direct constraints on the properties of individual AGNs, such as their emission, obscuration, and accretion rate. Previous AGN population synthesis models have not addressed such…

High Energy Astrophysical Phenomena · Physics 2026-05-19 D. Gerolymatou , S. Paltani , C. Ricci , T. T. Ananna

We aim to constrain the evolution of AGN as a function of obscuration using an X-ray selected sample of $\sim2000$ AGN from a multi-tiered survey including the CDFS, AEGIS-XD, COSMOS and XMM-XXL fields. The spectra of individual X-ray…

We present AGNfitter, a publicly available open-source algorithm implementing a fully Bayesian Markov Chain Monte Carlo method to fit the spectral energy distributions (SEDs) of active galactic nuclei (AGN) from the sub-mm to the UV,…

Astrophysics of Galaxies · Physics 2025-05-26 Gabriela Calistro-Rivera , Elisabeta Lusso , Joseph F. Hennawi , David W. Hogg
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