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We use nine years of gamma-ray data provided by the Fermi Large Area Telescope (LAT) to systematically study the light curves of more than two thousand active galactic nuclei (AGN) included in recent Fermi-LAT catalogs. Ten different…

High Energy Astrophysical Phenomena · Physics 2020-07-01 P. Peñil , A. Domínguez , S. Buson , M. Ajello , J. Otero-Santos , J. A. Barrio , R. Nemmen , S. Cutini , B. Rani , A. Franckowiak , E. Cavazzuti

Jetted Active Galactic Nuclei (AGN) exhibit variability across a wide range of time scales. Traditionally, this variability can often be modeled well as a stochastic process. However, in certain cases, jetted AGN variability displays…

High Energy Astrophysical Phenomena · Physics 2025-01-03 P. Penil , A. Domínguez , S. Buson , M. Ajello , S. Adhikari , A. Rico

Active Galactic Nuclei (AGN) sources feature supermassive black holes that launch relativistic plasma jets. They are key $\gamma$-ray sources providing a unique laboratory for studying extreme particle acceleration and plasma physics.…

High Energy Astrophysical Phenomena · Physics 2026-02-03 Luana Passos-Reis , Elisabete M. de Gouveia Dal Pino , Tarek Hassan , Santiago Pita , Alberto Domínguez

We considered the fourth catalog of gamma-ray point sources produced by the Fermi Large Area Telescope (LAT) and selected only jetted active galactic nuclei (AGN) or sources with no specific classification, but with a low-frequency…

We are compiling a new list of gamma-ray jetted active galactic nuclei (AGN), starting from the fourth catalog of point sources of the Fermi Large Area Telescope (LAT). Our aim is to prepare a list of jetted AGN with known redshifts and…

High Energy Astrophysical Phenomena · Physics 2021-10-06 L. Foschini , M. L. Lister , S. Antón , M. Berton , S. Ciroi , M. J. M. Marchã , M. Tornikoski , E. Järvelä , P. Romano , S. Vercellone , E. Dalla Bontà

A majority of the active galactic nuclei (AGN) in the local Universe are classified as low-luminosity AGN (LLAGN), having bolometric luminosities $\lesssim 10^{42} \ \mathrm{erg \ s^{-1}}$. Although high-energy gamma-ray emission is…

High Energy Astrophysical Phenomena · Physics 2026-04-08 Chris Karwin , Nikita Khatiya , Margot Boughelilba , Xiurui Zhao , Anita Reimer , Marco Ajello

As a critical part of the Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry (TANAMI) program, in November 2007 the Australia Telescope Compact Array (ATCA) started monitoring the radio spectra of a sample of…

High Energy Astrophysical Phenomena · Physics 2012-05-14 J. Stevens , P. G. Edwards , R. Ojha , M. Kadler , F. Hungwe , M. Dutka , S. Tingay , J. P. Macquart , A. Moin , J. Lovell , J. Blanchard

The revision of the fourth Fermi Large Area Telescope (LAT) catalog of gamma-ray point sources (rev4FGL) revealed that the gamma-ray sky is populated by emerging populations of jetted active galactic nuclei (AGN) other than blazars and…

High Energy Astrophysical Phenomena · Physics 2026-01-27 Luigi Foschini

The second Fermi-LAT source catalog (2FGL) is the deepest all-sky survey available in the gamma-ray band. It contains 1873 sources, of which 576 remain unassociated. Machine-learning algorithms can be trained on the gamma-ray properties of…

High Energy Astrophysical Phenomena · Physics 2014-01-29 M. Doert , M. Errando

We present the first Fermi Large Area Telescope (LAT) catalog of long-term $\gamma$-ray transient sources (1FLT). This comprises sources that were detected on monthly time intervals during the first decade of Fermi-LAT operations. The…

High Energy Astrophysical Phenomena · Physics 2021-09-29 L. Baldini , J. Ballet , D. Bastieri , J. Becerra Gonzalez , R. Bellazzini , A. Berretta , E. Bissaldi , R. D. Blandford , E. D. Bloom , R. Bonino , E. Bottacini , P. Bruel , S. Buson , R. A. Cameron , P. A. Caraveo , E. Cavazzuti , S. Chen , G. Chiaro , D. Ciangottini , S. Ciprini , P. Cristarella Orestano , M. Crnogorcevic , S. Cutini , F. D'Ammando , P. de la Torre Luque , F. de Palma , S. W. Digel , N. Di Lalla , F. Dirirsa , L. Di Venere , A. Domínguez , A. Fiori , H. Fleischhack , A. Franckowiak , Y. Fukazawa , S. Funk , P. Fusco , F. Gargano , D. Gasparrini , S. Germani , N. Giglietto , F. Giordano , M. Giroletti , D. Green , I. A. Grenier , S. Griffin , S. Guiriec , M. Gustafsson , J. W. Hewitt , D. Horan , R. Imazawa , G. Jóhannesson , M. Kerr , D. Kocevski , M. Kuss , S. Larsson , L. Latronico , J. Li , I. Liodakis , F. Longo , F. Loparco , M. N. Lovellette , P. Lubrano , S. Maldera , A. Manfreda , G. Martí-Devesa , H. Matake , M. N. Mazziotta , I. Mereu , M. Meyer , N. Mirabal , W. Mitthumsiri , T. Mizuno , M. E. Monzani , A. Morselli , I. V. Moskalenko , S. Nagasawa , M. Negro , R. Ojha , M. Orienti , E. Orlando , M. Palatiello , V. Paliya , D. Paneque , Z. Pei , M. Persic , M. Pesce-Rollins , V. Petrosian , H. Poon , T. A. Porter , G. Principe , J. L. Racusin , S. Rainò , R. Rando , B. Rani , M. Razzano , S. Razzaque , A. Reimer , O. Reimer , P. M. Saz Parkinson , L. Scotton , D. Serini , C. Sgrò , E. J. Siskind , G. Spandre , P. Spinelli , D. J. Suson , H. Tajima , D. Tak , D. F. Torres , G. Tosti , E. Troja , K. Wood , M. Yassine , G. Zaharijas

Variability studies of jetted AGN, in particular blazars, have been used to gain a better understanding of the particle acceleration mechanisms in jets. However, statistical methods used for the characterization of variability often rely on…

High Energy Astrophysical Phenomena · Physics 2025-12-23 Andrea Gokus , Rebecca Phillipson

The Large Area Telescope (LAT) aboard the $Fermi$ spacecraft routinely observes high-energy emission from gamma-ray bursts (GRBs). Here we present the second catalog of LAT-detected GRBs, covering the first 10 years of operations, from 2008…

High Energy Astrophysical Phenomena · Physics 2019-06-28 M. Axelsson , E. Bissaldi , N. Omodei , G. Vianello

Blazars are known to exhibit variability across a broad range of timescales. This behavior can include periodicity in their $\gamma$-ray emission, whose clear detection remains an ongoing challenge, partly due to the inherent stochasticity…

High Energy Astrophysical Phenomena · Physics 2025-07-08 P. Peñil , M. Ajello , S. Buson , A. Domínguez , J. R. Westernacher-Schneider , A. Rico , S. Adhikari , J. Zrake

This paper investigates a new methodology to search for periods in light-curves of high-energy gamma-ray sources such as Active Galactic Nuclei (AGNs). High-energy light curves have significant stochastic components, making period detection…

High Energy Astrophysical Phenomena · Physics 2022-07-27 Héctor Rueda , Jean-François Glicenstein , François Brun

The extragalactic gamma-ray sky is dominated by relativistic jets aligned to the observer's line of sight, i.e., blazars. A few of their misaligned counterparts, e.g., radio galaxies, are also detected with the Fermi-Large Area Telescope…

High Energy Astrophysical Phenomena · Physics 2024-10-15 Vaidehi S. Paliya , D. J. Saikia , Alberto Domínguez , C. S. Stalin

We perform a multi-band statistical analysis of core-dominated superluminal active galactic nuclei (AGN) detected with Fermi Large Area Telescope (LAT). The detection rate of $\gamma$-ray jets is found to be high for optically bright AGN.…

Cosmology and Nongalactic Astrophysics · Physics 2010-06-14 T. G. Arshakian , J. León-Tavares , J. Torrealba , V. H. Chavushyan

In three years of observations since the beginning of nominal science operations in August 2008, the Large Area Telescope (LAT) on board the Fermi Gamma Ray Space Telescope has observed high-energy (>20 MeV) \gamma-ray emission from 35…

High Energy Astrophysical Phenomena · Physics 2015-06-15 LAT Collaboration

We report the detection of a gamma-ray spectral line at approximately 1.5 GeV in three active galactic nuclei (AGN) using 17 years of Fermi-LAT observations. The sample includes both blazars (with relativistic jets directed toward Earth)…

High Energy Astrophysical Phenomena · Physics 2026-04-02 Shi-Ju Kang , Yue Yin , Yong-Gang Zheng , Qingwen Wu

The detection of very-high-energy (VHE; $>$100 GeV) $\gamma$-ray radiation from misaligned jetted Active Galactic Nuclei (AGN) challenges the emission models that primarily explain VHE emissions from beamed AGN, i.e., blazars. Using over 16…

High Energy Astrophysical Phenomena · Physics 2025-08-25 Gunjan Tomar , Vaidehi S. Paliya , D. J. Saikia , C. S. Stalin

Active galactic nuclei (AGN) with jets seen at small viewing angles are the most luminous and abundant objects in the $\gamma$-ray sky. AGN with jets misaligned along the line-of-sight appear fainter in the sky, but are more numerous than…

High Energy Astrophysical Phenomena · Physics 2015-06-15 M. Di Mauro , F. Calore , F. Donato , M. Ajello , L. Latronico
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