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Active galactic nuclei (AGN) are known as sources of high energy gamma-rays. The emission probably results from non-thermal radiation of relativistic jets belonging to the AGN. Earlier investigations of these processes have suggested that…

Astrophysics · Physics 2009-11-07 C. Schuster , M. Pohl , R. Schlickeiser

Heavily obscured Active Galactic Nuclei (AGN), especially Compton-thick sources with line-of-sight column density ($N_{\rm H,los}$) $>$ 10$^{24}$ cm$^{-2}$, are critical to understanding supermassive black hole (SMBH) growth and the origin…

We investigate spatially-resolved emission-line ratios in a sample of 219 galaxies ($0.6<z<1.3$) detected using the G102 grism on the \emph{Hubble Space Telescope} Wide Field Camera 3, taken as part of the CANDELS Ly$\alpha$ Emission at…

By combining the 2-degree Field Galaxy Redshift Survey with the NRAO VLA Sky Survey at 1.4 GHz, the environments of radio loud AGN in the nearby Universe are investigated using both local projected galaxy densities and a friends-of-friends…

Astrophysics · Physics 2009-11-10 P. N. Best

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…

Active galactic nuclei (AGN) are a promising source for high-energy astrophysical neutrinos (HEANs). By the end of 2022, the Vera C. Rubin Observatory (VRO) will begin to observe $\gtrsim10$ million AGN with a regular and high cadence.…

High Energy Astrophysical Phenomena · Physics 2022-07-13 Cyril Creque-Sarbinowski , Marc Kamionkowski , Bei Zhou

We present the results from 685 MHz observations with the upgraded Giant Metrewave Radio Telescope (uGMRT) of 22 quasars belonging to the Palomar-Green (PG) quasar sample. Only four sources reveal extended radio structures on $\sim$10-30…

Astrophysics of Galaxies · Physics 2020-12-22 Silpa S. , P. Kharb , L. C. Ho , C. H. Ishwara-Chandra , M. E. Jarvis , C. Harrison

It is well-known that star-forming galaxies (SFGs) exhibit a tight correlation between their radio and infrared emissions, commonly referred to as the infrared-radio correlation (IRRC). Recent empirical studies have reported a dependence of…

The physical origin of radio emission in Radio Quiet Active Galactic Nuclei (RQ AGN) remains unclear, whether it is a downscaled version of the relativistic jets typical of Radio Loud (RL) AGN, or whether it originates from the accretion…

Astrophysics of Galaxies · Physics 2015-08-06 Ehud Behar , Ranieri D. Baldi , Ari Laor , Assaf Horesh , Jamie Stevens , Tasso Tzioumis

We review the current understanding of the diffuse gamma-ray background (DGRB). The DGRB is what remains of the total measured gamma-ray emission after the subtraction of the resolved sources and of the diffuse Galactic foregrounds. It is…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-28 Mattia Fornasa , Miguel A. Sanchez-Conde

The NASA/ISO Key Project on active galactic nuclei (AGN) seeks to better understand the broad-band spectral energy distributions (SEDs) of these sources from radio to X-rays, with particular emphasis on infrared properties. The ISO sample…

The unified model of active galactic nuclei (AGN) claims that the properties of AGN depend on the viewing angle of the observer with respect to a toroidal distribution of dust surrounding the nucleus. Both the mid-infrared (MIR) attenuation…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 O. Gonzalez-Martin , J. M. Rodriguez-Espinosa , T. Diaz-Santos , C. Packham , A. Alonso-Herrero , P. Esquej , C. Ramos Almeida , R. Mason , C. Telesco

The 232U content of various uranium-bearing items was measured using low-background gamma spectrometry. The method is independent of the measurement geometry, sample form and chemical composition. Since 232U is an artificially produced…

Nuclear Experiment · Physics 2015-08-10 Jozsef Zsigrai , Tam Cong Nguyen , Andrey Berlizov

The ARGO-YBJ experiment is a full coverage air shower array; its lowest energy threshold is reached using the "scaler mode technique". Working in this mode, the signals generated by any particle hitting each cluster are put in coincidence…

Instrumentation and Methods for Astrophysics · Physics 2015-06-03 Elio Giroletti , Irene Bolognino , Claudio Cattaneo , Giuseppe Liguori , Paola Salvini , Piero Vallania , Carlo Vigorito

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

Active galactic nuclei (AGNs) have been one of the most widely discussed sources of ultrahigh-energy cosmic rays (UHECRs). The recent results of Pierre Auger observatory (PAO) have indicated a possible composition change of UHECRs above…

High Energy Astrophysical Phenomena · Physics 2010-01-07 Asaf Pe'er , Kohta Murase , Peter Mészáros

We present a comprehensive study of the physical origin of radio emission in optical quasars at redshifts z < 2.5. We focus particularly on the associations between compact radio emission, dust reddening, and outflows identified in our…

Near-Eddington radiation from active galactic nuclei (AGNs) has significant dynamical influence on the surrounding dusty gas, plausibly furnishing AGNs with geometrically thick obscuration. We investigate this paradigm with radiative…

Astrophysics of Galaxies · Physics 2017-08-21 Chi-Ho Chan , Julian H. Krolik

Recently, a large number of compact sources at $z > 4$ with blue UV slopes and extremely red rest-frame optical slopes have been found in James Webb Space Telescope (JWST) extragalactic surveys. As a subsample of these sources, commonly…

Aims. We present an innovative artificial neural network (ANN) architecture, called Generative ANN (GANN), that computes the forward model, that is it learns the function that relates the unknown outputs (stellar atmospheric parameters, in…

Instrumentation and Methods for Astrophysics · Physics 2016-10-19 C. Dafonte , D. Fustes , M. Manteiga , D. Garabato , M. A. Alvarez , A. Ulla , C. Allende Prieto
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