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The third catalog of active galactic nuclei (AGNs) detected by the Fermi Large Area Telescope (3LAC) is presented. It is based on the third catalog (3FGL,\cite{3FGL}) of sources detected with a test statistic greater than 25, using the…

High Energy Astrophysical Phenomena · Physics 2019-08-14 Dario Gasparrini , Benoit Lott , Sara Cutini , Stefano Ciprini , Elisabetta Cavazzuti

The fourth Fermi Large Area Telescope (LAT) catalog (4FGL) contains 5064 $\gamma$-ray sources detected at high significance, but 26% of them still lack associations at other wavelengths. The SPT-SZ survey, conducted between 2008 and 2011…

High Energy Astrophysical Phenomena · Physics 2023-01-04 Lizhong Zhang , Joaquin D. Vieira , Marco Ajello , Matthew A. Malkan , Melanie A. Archipley , Joseph Capota , Allen Foster , Greg Madejski

With a decade of gamma-ray data from the Fermi-LAT telescope, we can now hope to answer how well we know the local Universe at gamma-ray frequencies. On the other hand, with gamma-ray data alone it is not possible to directly access the…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-27 Simone Ammazzalorso , Nicolao Fornengo , Shunsaku Horiuchi , Marco Regis

Following our work presented in Dai et al. (2016), we report our detailed data analysis for another 38 Fermi gamma-ray un-associated sources. These sources are selected from the Fermi Large Area Telescope (LAT) third source catalog on the…

High Energy Astrophysical Phenomena · Physics 2021-06-03 Xuejie Dai , Zhongxiang Wang , V. Jithesh , Yi Xing

We present the first catalog of active galactic nuclei (AGN) detected by the LAT, corresponding to 11 months of data collected in scientific operation mode. The First LAT AGN Catalog (1LAC) includes 671 gamma-ray sources located at high…

High Energy Astrophysical Phenomena · Physics 2019-08-14 A. A. Abdo

We have analyzed all the archival X-ray data of 134 unidentified (unID) gammaray sources listed in the first Fermi/LAT (1FGL) catalog and subsequently followed up by Swift/XRT. We constructed the spectral energy distributions (SEDs) from…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Y. Takeuchi , J. Kataoka , K. Maeda , Y. Takahashi , T. Nakamori , M. Tahara

We present an incremental version (4FGL-DR4, for Data Release 4) of the fourth Fermi-LAT catalog containing 7194 gamma-ray sources. Based on the first 14 years of science data in the energy range from 50 MeV to 1 TeV, it uses the same…

High Energy Astrophysical Phenomena · Physics 2024-07-25 J. Ballet , P. Bruel , T. H. Burnett , B. Lott , The Fermi-LAT collaboration

A significant fraction of all $\gamma$-ray sources detected by the Large Area Telescope aboard the \fer\ satellite is still lacking a low-energy counterpart. In addition, there is still a large population of $\gamma$-ray sources with…

In the 4FGL-DR4 point-source catalog of the Large Area Telescope (LAT) onboard NASA's Fermi Gamma-ray Observatory (Fermi-LAT), around a third of the sources are still unidentified (unIDs). In this work, we perform a detailed study of one of…

About one third of Fermi Large Area Telescope (LAT) sources are unassociated. We perform multi-class classification of Fermi-LAT sources using machine learning with the goal of probabilistic classification of the unassociated sources. A…

High Energy Astrophysical Phenomena · Physics 2025-03-07 Dmitry V. Malyshev

We discuss a new method for unveiling the possible blazar AGN nature among the numerous population of Unassociated Gamma-ray sources (UGS) in the Fermi catalogues. Our tool relies on positional correspondence of the Fermi object with X-ray…

High Energy Astrophysical Phenomena · Physics 2017-05-31 Simona Paiano , Alberto Franceschini , Antonio Stamerra

Machine learning has emerged as a powerful tool in the field of gamma-ray astrophysics. The algorithms can distinguish between different source types, such as blazars and pulsars, and help uncover new insights into the high-energy universe.…

High Energy Astrophysical Phenomena · Physics 2024-01-05 Gopal Bhatta , Sarvesh Gharat , Abhimanyu Borthakur , Aman Kumar

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

High Energy Astrophysical Phenomena · Physics 2015-06-19 A. Paggi , F. Massaro , R. D'Abrusco , H. A. Smith , N. Masetti , M. Giroletti , G. Tosti , S. Funk

Aims. In this paper, we searched for multi-wavelength (X-ray, optical and radio) counterparts to the unassociated gamma-ray sources (UGS) of the Fermi 4FGL-DR4 catalog. The main goal is to identify new blazars and/or new active galactic…

An analytic relation between the statistics of photons in pixels and the number counts of multi-photon point sources is used to constrain the distribution of gamma-ray point sources below the Fermi detection limit at energies above 1 GeV…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-06 Dmitry Malyshev , David W. Hogg

Studying unidentified {\gamma}-ray sources is important as they may hide new discoveries. We conducted a multiwavelength analysis of 13 unidentified Fermi-LAT sources in the 3FGL catalog that have no known counterparts (Unidentified…

High Energy Astrophysical Phenomena · Physics 2021-07-14 Jean Damascène Mbarubucyeye , Felicia Krauß , Pheneas Nkundabakura

We present a catalog of sources of very high energy (E>100 GeV) gamma-rays detected by the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope at Galactic latitudes |b|>=10 degrees. We cross-correlate the directions of…

High Energy Astrophysical Phenomena · Physics 2015-05-18 A. Neronov , D. V. Semikoz , Ie. Vovk

Analysis is presented on 15 months of data taken with the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope for 11 non-blazar AGNs, including 7 FRI radio galaxies and 4 FRII radio sources consisting of 2 FRII radio galaxies…

High Energy Astrophysical Phenomena · Physics 2017-02-22 LAT Collaboration

To understand Galactic objects that emits GeV-TeV emission, a spatial correlation study between the Fermi bright source catalog and TeV source population was carried out in Tam et al. (2010), finding that a significant number of very…

High Energy Astrophysical Phenomena · Physics 2011-11-07 P. Tam , S. Wagner

The second catalog of active galactic nuclei (AGNs) detected by the Fermi Large Area Telescope (LAT) in two years of scientific operation is presented. The Second LAT AGN Catalog (2LAC) includes 1017 gamma-ray sources located at high…

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