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Related papers: Reconstructing AGN X-ray spectral parameter distri…

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We constrain X-ray spectral shapes for the ensemble of AGN based on the shape of the Cosmic X-ray Background (CXB). Specifically, we rule out regions of X-ray spectral parameter space that do not reproduce the CXB in the energy range 1-100…

Over the past 10 years Bayesian methods have rapidly grown more popular as several computationally intensive statistical algorithms have become feasible with increased computer power. In this paper, we begin with a general description of…

Astrophysics · Physics 2016-02-19 David A. van Dyk , Alanna Connors , Vinay L. Kashyap , Aneta Siemiginowska

X-rays provide a robust method in identifying AGN. However, in the high-redshift Universe, their space density is relatively low, and, in combination with the small areas covered by X-ray surveys, the selected AGN are poorly sampled. Deep…

Astrophysics of Galaxies · Physics 2025-05-21 E. Pouliasis , A. Ruiz , I. Georgantopoulos , A. Akylas , N. A. Webb , F. J. Carrera , S. Mateos , A. Nebot , M. G. Watson , F. X. Pineau , C. Motch

The fraction of AGN luminosity obscured by dust and re-emitted in the mid-IR is critical for understanding AGN evolution, unification, and parsec-scale AGN physics. For unobscured (Type-1) AGN, where we have a direct view of the accretion…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 E. Lusso , J. F. Hennawi , A. Comastri , G. Zamorani , G. T. Richards , C. Vignali , E. Treister , K. Schawinski , M. Salvato , R. Gilli

In this paper, we propose a Bayesian spectral deconvolution considering the properties of peaks in different energy domains. Bayesian spectral deconvolution regresses spectral data into the sum of multiple basis functions. Conventional…

Approximate Bayesian Computation is a family of likelihood-free inference techniques that are well-suited to models defined in terms of a stochastic generating mechanism. In a nutshell, Approximate Bayesian Computation proceeds by computing…

Computation · Statistics 2010-07-28 Michael Blum

We develop a new diagnostic method to classify galaxies into AGN hosts, star-forming galaxies, and absorption-dominated galaxies by combining the [O III]/Hbeta ratio with rest-frame U-B color. This can be used to robustly select AGNs in…

This paper addresses the challenge of obtaining precise demographic information at a fine-grained spatial level, a necessity for planning localized public services such as water distribution networks, or understanding local human impacts on…

Methodology · Statistics 2024-07-17 Anis Pakrashi , Arnab Hazra , Sooraj M Raveendran , Krishnachandran Balakrishnan

Approximate Bayesian inference on the basis of summary statistics is well-suited to complex problems for which the likelihood is either mathematically or computationally intractable. However the methods that use rejection suffer from the…

Computation · Statistics 2010-05-04 M. G. B. Blum , O. Francois

The XLF of AGN offers a robust tool to study the evolution and the growth of SMBHs over cosmic time. Owing to the limited area probed by X-ray surveys, optical surveys are routinely used to probe the accretion in the high redshift Universe…

We present optical spectroscopy for an X-ray and optical flux-limited sample of 677 XMM-Newton selected targets covering the 2 deg^2 COSMOS field, with a yield of 485 high-confidence redshifts. The majority of the spectra were obtained over…

Weak lensing measurements are starting to provide statistical maps of the distribution of matter in the universe that are increasingly precise and complementary to cosmic microwave background maps. The probability distribution (PDF)…

Astrophysics · Physics 2009-11-10 Tong-Jie Zhang , Ue-Li Pen

State-of-the-art image-set matching techniques typically implicitly model each image-set with a Gaussian distribution. Here, we propose to go beyond these representations and model image-sets as probability distribution functions (PDFs)…

Computer Vision and Pattern Recognition · Computer Science 2015-08-03 Mehrtash Harandi , Mathieu Salzmann , Mahsa Baktashmotlagh

We present a machine learning model to classify Active Galactic Nuclei (AGN) and galaxies (AGN-galaxy classifier) and a model to identify type 1 (optically unabsorbed) and type 2 (optically absorbed) AGN (type 1/2 classifier). We test…

Astrophysics of Galaxies · Physics 2021-12-08 Serena Falocco , Francisco J. Carrera , Josefin Larsson

Parton distribution functions (PDFs) form an essential part of particle physics calculations. Currently, the most precise predictions for these non-perturbative functions are generated through fits to global data. A problem that several PDF…

High Energy Physics - Phenomenology · Physics 2025-09-04 Mengshi Yan , Tie-Jiun Hou , Zhao Li , Kirtimaan Mohan , C. -P. Yuan

This paper provides a review of Approximate Bayesian Computation (ABC) methods for carrying out Bayesian posterior inference, through the lens of density estimation. We describe several recent algorithms and make connection with traditional…

Computation · Statistics 2019-09-09 Clara Grazian , Yanan Fan

The detection of X-ray emission constitutes a reliable and efficient tool for the selection of Active Galactic Nuclei (AGNs), although it may be biased against the most heavily absorbed AGNs. Simple mid-IR broad-band selection criteria…

Astrophysics of Galaxies · Physics 2020-05-06 E. Pouliasis , G. Mountrichas , I. Georgantopoulos , A. Ruiz , M. Yang , A. Z. Bonanos

We explore the application of Bayesian image analysis to infer the properties of an SDSS early-type galaxy sample including AGN. We use GALPHAT (Yoon et al. 2010) with a Bayes-factor model comparison to photometrically infer an AGN…

Cosmological inference becomes increasingly difficult when complex data-generating processes cannot be modeled by simple probability distributions. With the ever-increasing size of data sets in cosmology, there is increasing burden placed…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Anja Weyant , Chad Schafer , W. Michael Wood-Vasey

We present a composite machine learning framework to estimate posterior probability distributions of bulge-to-total light ratio, half-light radius, and flux for Active Galactic Nucleus (AGN) host galaxies within $z<1.4$ and $m<23$ in the…