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The Fermi/LAT telescope is an efficient blazar-detector in the MeV/GeV range. More than 1100 (900) blazars detected above 100 MeV (10 GeV) are clearly associated to BL Lacertae or Flat Spectrum Radio Quasar objects in the Fermi/LAT 3FGL…

High Energy Astrophysical Phenomena · Physics 2017-10-02 Julien Lefaucheur , Catherine Boisson , Paolo Goldoni , Santiago Pita

An incremental version (4LAC-DR2) of the fourth catalog of active galactic nuclei (AGNs) detected by the Fermi-LAT is presented. This version is associated with the second release of the 4FGL general catalog (based on 10 years of data),…

High Energy Astrophysical Phenomena · Physics 2020-10-19 B. Lott , D. Gasparrini , S. Ciprini

During its first four years of scientific observations, the Fermi Large Area Telescope (Fermi-LAT) detected 3033 $\gamma$-ray sources above a 4$\sigma$ significance level. Although most of the extra-Galactic sources are active galactic…

High Energy Astrophysical Phenomena · Physics 2019-08-15 G. La Mura , G. Chiaro , S. Ciroi , P. Rafanelli , D. Salvetti , M. Berton , V. Cracco

We conduct X-ray spectral fits on 184 likely counterparts to Fermi-LAT 3FGL unassociated sources. Characterization and classification of these sources allows for more complete population studies of the high-energy sky. Most of these X-ray…

High Energy Astrophysical Phenomena · Physics 2021-03-02 Stephen Kerby , Amanpreet Kaur , Abraham D. Falcone , Michael C. Stroh , Elizabeth C. Ferrara , Jamie A. Kennea , Joseph Colosimo

We cross correlate the Fermi 11 months survey catalogue (1FGL) with the 20 GHz Australia Telescope Compact Array radio survey catalogue (AT20G) composed by 5890 sources at declination <0 deg. Among the 738 Fermi sources distributed in the…

High Energy Astrophysical Phenomena · Physics 2015-05-18 G. Ghirlanda , G. Ghisellini , F. Tavecchio , L. Foschini

Context. Although Blazars are a small fraction of the overall AGN population they are expected to be the dominant population of extragalactic sources in the hard X-ray and gamma-ray bands and have been shown to be the largest contaminant of…

Astrophysics · Physics 2008-11-26 S. Turriziani , E. Cavazzuti , P. Giommi

We present a systematic search for spatial association between a high confidence sample of 3,166 morphologically selected galaxy mergers drawn from the initial convolutional neural network (CNN) catalog of 328,151 candidate mergers and…

High Energy Astrophysical Phenomena · Physics 2025-09-15 Siddhant Manna , Shantanu Desai

The Fermi Large Area Telescope First Source Catalog (1FGL) provided spatial, spectral, and temporal properties for a large number of gamma-ray sources using a uniform analysis method. After correlating with the most-complete catalogs of…

High Energy Astrophysical Phenomena · Physics 2015-05-30 LAT Collaboration

The Fermi gamma-ray space telescope has revolutionized our view of the gamma-ray sky and the high energy processes in the Universe. While the number of known gamma-ray emitters has increased by orders of magnitude since the launch of Fermi,…

High Energy Astrophysical Phenomena · Physics 2019-05-01 I. Liodakis , D. Blinov

The fourth-DR3 version (4FGL-DR3) of the Fermi/LAT catalogue of $\gamma$-ray sources contains $\sim$ 1000 objects at a galactic latitude |b| > 10$^{\circ}$ which are not identified with an optical counterpart (UGS). We performed a…

High Energy Astrophysical Phenomena · Physics 2024-02-20 Alberto Ulgiati , Simona Paiano , Aldo Treves , Renato Falomo , Boris Sbarufatti , Fabio Pintore , Thomas D. Russell , Giancarlo Cusumano

The parsec-scale radio properties of 232 active galactic nuclei (AGNs), most of which are blazars, detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope have been observed contemporaneously by the Very Long…

High Energy Astrophysical Phenomena · Physics 2015-06-11 J. D. Linford , G. B. Taylor , F. K. Schinzel

Context. Based on their overwhelming dominance among associated Fermi gamma ray catalogue sources, it is expected that a large fraction of the unidentified Fermi objects are blazars. Through crossmatching between the positions of…

In this work, we make use of a supervised machine learning algorithm based on Logistic Regression (LR) to select TeV blazar candidates from the 4FGL-DR2 / 4LAC-DR2, 3FHL, 3HSP, and 2BIGB catalogs. LR constructs a hyperplane based on a…

High Energy Astrophysical Phenomena · Physics 2023-06-28 J. T. Zhu , C. Lin , H. B. Xiao , J. H. Fan , D. Bastieri , G. G. Wang

Blazars are among the most studied sources in high-energy astrophysics as they form the largest fraction of extragalactic gamma-ray sources and are considered prime candidates for being the counterparts of high-energy astrophysical…

(Abridged) We carried out an extensive search to identify the counterparts of all the sources listed in the WMAP 3-yr catalogue using literature and archival data. Our work led to the identification of 309 WMAP sources, 98% of which are…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 P. Giommi , S. Colafrancesco , P. Padovani , D. Gasparrini , E. Cavazzuti , S. Cutini

We report our identification of three gigaelectronvolt $\gamma$-ray sources, 4FGL J0502.6+0036, 4FGL J1055.9+6507, and 4FGL J1708.2+5519, as Active Galactic Nuclei (AGNs). They are listed in the latest Fermi-LAT source catalog as…

High Energy Astrophysical Phenomena · Physics 2024-06-21 Shunhao Ji , Zhongxiang Wang , Qiangmeng Huang , Ruoheng Yang

A significant fraction ($\sim 30$ %) of the gamma-ray sources listed in the second $\textit{Fermi}$ LAT (2FGL) catalog is still of unknown origin, being not yet associated with counterparts at lower energies. Using the available information…

We present the first measurement of the projected correlation function of 485 gamma-ray selected Blazars, divided in 175 BLLacertae (BL Lacs) and 310 Flat Spectrum Radio Quasars (FSRQs) detected in the 2-year all-sky survey by Fermi-Large…

Astrophysics of Galaxies · Physics 2015-06-23 Viola Allevato , Alexis Finoguenov , Nico Cappelluti

The Fermi Large Area Telescope (Fermi-LAT) 3FHL catalog is the latest catalog of >10 GeV sources and will remain an important resource for the high-energy community for the foreseeable future. Therefore, it is crucial that this catalog is…

High Energy Astrophysical Phenomena · Physics 2020-10-14 Ross Silver , Stefano Marchesi , Lea Marcotulli , Aman Kaur , Meenakshi Rajagopal , Marco Ajello

The use of Bayesian neural networks is a novel approach for the classification of gamma-ray sources. We focus on the classification of Fermi-LAT blazar candidates, which can be divided into BL Lacertae objects and Flat Spectrum Radio…

High Energy Astrophysical Phenomena · Physics 2022-05-13 Anja Butter , Thorben Finke , Felicitas Keil , Michael Krämer , Silvia Manconi