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We present a catalog of gamma-ray sources at energies above 10 GeV based on data from the Large Area Telescope (LAT) accumulated during the first three years of the Fermi Gamma-ray Space Telescope mission. The first Fermi-LAT catalog of…

Instrumentation and Methods for Astrophysics · Physics 2015-06-16 LAT Collaboration

The gamma-ray sky >100 MeV is dominated by the diffuse emissions from interactions of cosmic rays with the interstellar gas and radiation fields of the Milky Way. Observations of these diffuse emissions provide a tool to study cosmic-ray…

High Energy Astrophysical Phenomena · Physics 2015-06-04 LAT Collaboration

After almost 4 years of operation, the two instruments onboard the Fermi Gamma-ray Space Telescope have shown that the number of gamma-ray bursts with high energy photon emission above 100 MeV cannot exceed roughly 9% of the total number of…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Carl W. Akerlof , WeiKang Zheng

We combine adaptive template fitting and pixel count statistics in order to assess the nature of the Galactic center excess in Fermi-LAT data. We reconstruct the flux distribution of point sources well below the Fermi-LAT detection…

High Energy Astrophysical Phenomena · Physics 2021-10-29 Francesca Calore , Fiorenza Donato , Silvia Manconi

Despite the growing number of gamma-ray sources detected by Fermi-LAT, about one third of the sources in each survey remains of uncertain type. We present a new deep neural network approach for the classification of unidentified or…

High Energy Astrophysical Phenomena · Physics 2021-09-28 Thorben Finke , Michael Krämer , Silvia Manconi

The Fermi-LAT telescope has measured the extragalactic gamma-ray background (EGB) generated by the ensemble of all extragalactic sources. The energy distribution of the EGB is well described as a power-law with a spectral index…

High Energy Astrophysical Phenomena · Physics 2020-09-09 Paolo Lipari

We present the second catalog of high-energy gamma-ray sources detected by the Large Area Telescope (LAT), the primary science instrument on the Fermi Gamma-ray Space Telescope (Fermi), derived from data taken during the first 24 months of…

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

Observations by the Large Area Telescope (LAT) on the \textit{Fermi} mission of diffuse $\gamma$-rays in a mid-latitude region in the third quadrant (Galactic longitude $l$ from $200\arcdeg$ to $260\arcdeg$ and latitude $| b |$ from…

High Energy Astrophysical Phenomena · Physics 2009-12-04 A. A. Abdo

We estimate the galaxy density along lines of sight to hard extragalactic gamma-ray sources by correlating source positions on the sky with a void catalog based on the Sloan Digital Sky Survey (SDSS). Extragalactic gamma-ray sources that…

High Energy Astrophysical Phenomena · Physics 2015-06-22 A. Furniss , P. M. Sutter , J. R. Primack , A. Dominguez

The Large Area Telescope (LAT) on board the \emph{Fermi} Gamma-ray Space Telescope has been continuously providing good quality survey data of the entire sky in the high energy range from 30 MeV to 500 GeV and above since August 2008. A…

High Energy Astrophysical Phenomena · Physics 2025-10-13 A. Pathania , K. K. Singh , S. K. Singh , A. Tolamatti , B. B. Singh , K. K. Yadav

Millisecond Pulsars are second most abundant source population discovered by the Fermi-LAT. They might contribute non-negligibly to the diffuse emission measured at high latitudes by Fermi-LAT, the IDGRB. Gamma-ray sources also contribute…

High Energy Astrophysical Phenomena · Physics 2014-11-05 F. Calore , M. Di Mauro , F. Donato

Here is reviewed our current understanding of Galactic and extragalactic diffuse gamma-ray emission. The spectrum of the extragalactic gamma-ray background above 30 MeV can be well described by a power law with photon index s=2.1. In the…

Astrophysics · Physics 2007-05-23 Martin Pohl

Detection of point sources in images is a fundamental operation in astrophysics, and is crucial for constraining population models of the underlying point sources or characterizing the background emission. Standard techniques fall short in…

Instrumentation and Methods for Astrophysics · Physics 2018-02-28 Tansu Daylan , Stephen K. N. Portillo , Douglas P. Finkbeiner

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…

We report the discovery of high-energy (E>100 MeV) gamma-ray emission from NGC 1275, a giant elliptical galaxy lying at the center of the Perseus cluster of galaxies, based on observations made with the Large Area Telescope (LAT) of the…

High Energy Astrophysical Phenomena · Physics 2012-08-27 LAT Collaboration , A. A. Abdo , H. D. Aller , M. F. Aller , K. I. Kellermann , Y. Y. Kovalev , Y. A. Kovalev , M. L. Lister , A. B. Pushkarev

Using 3.7 years of \Fermi-LAT data, we examine the diffuse 80-200 GeV emission in the inner Galaxy and find a resolved gamma-ray feature at $\sim 110-140$ GeV. We model the spatial distribution of this emission with a $\sim3\degree$ FWHM…

High Energy Astrophysical Phenomena · Physics 2012-06-15 Meng Su , Douglas P. Finkbeiner

We propose a novel statistical method to extend Fermi-LAT catalogues of high-latitude $\gamma$-ray sources below their nominal threshold. To do so, we rely on a recent determination of the differential source-count distribution of…

High Energy Astrophysical Phenomena · Physics 2024-05-16 Aurelio Amerio , Francesca Calore , Pasquale Dario Serpico , Bryan Zaldivar

The diffuse Galactic gamma-ray emission is produced by cosmic rays (CRs) interacting with the interstellar gas and radiation field. Measurements by the Energetic Gamma-Ray Experiment Telescope (EGRET) instrument on the Compton Gamma-Ray…

High Energy Astrophysical Phenomena · Physics 2019-08-13 T. A. Porter

We present a catalog of gamma-ray sources at energies above 10 GeV based on data from the Large Area Telescope (LAT) accumulated during the first 3 years of the Fermi Gamma-ray Space Telescope mission. This catalog complements the Second…

High Energy Astrophysical Phenomena · Physics 2013-04-16 David Paneque , Jean Ballet , Toby Burnett , Seth Digel , Pascal Fortin , Juergen Knoedlseder

The distribution on the sky of unidentified sources at the highest energies where such a population is evident is investigated. For this purpose, sources without identification in the first Fermi-LAT catalog >10 GeV (1FHL) that are good…

High Energy Astrophysical Phenomena · Physics 2014-12-08 Wilfried F. Domainko