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The Fermi Large Area Telescope (LAT) has detected thousands of sources since its launch in 2008, with many remaining unidentified. Some of these point sources may arise from source confusion. Specifically, there could be extended sources…

High Energy Astrophysical Phenomena · Physics 2025-04-07 Giovanni Cozzolongo , Alison M. W. Mitchell , Samuel T. Spencer , Dmitry Malyshev , Tim Unbehaun

Approximately one-third of the gamma-ray sources in the third Fermi-LAT catalog are unidentified or unassociated with objects at other wavelengths. Observations with Swift-XRT have yielded possible counterparts in $\sim$30% of these source…

High Energy Astrophysical Phenomena · Physics 2020-01-08 Amanpreet Kaur , Abraham D Falcone , Michael D Stroh , Jamie A Kennea , Elizabeth C Ferrara

The diffuse Galactic gamma-ray data from the region of the Galactic Center has been collected by the LAT instrument on the Fermi Gamma-Ray Space Telescope. In this paper we argue that it may be able to provide an unambiguous evidence of…

High Energy Astrophysical Phenomena · Physics 2009-09-09 Leszek Roszkowski , Yue-Lin Sming Tsai

The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope (formerly GLAST), with its improved sensitivity relative to previous generation gamma-ray telescopes, is significantly increasing the number of known gamma-ray sources in…

Astrophysics of Galaxies · Physics 2019-08-13 P. M. Saz Parkinson , M. Dormody , M. Ziegler

We present the results of a cluster search in the Fermi-LAT Pass 8 gamma-ray sky by means of the Minimum Spanning Tree algorithm, at energies higher than 10 GeV and at Galactic latitudes higher than 25 degrees. The selected clusters have a…

High Energy Astrophysical Phenomena · Physics 2016-11-07 R. Campana , E. Massaro , E. Bernieri

Unassociated Fermi-LAT sources provide a population with discovery potential. We discuss efforts to find new source associations for this population, and summarize the successes to date. We discuss how the measured gamma-ray properties of…

High Energy Astrophysical Phenomena · Physics 2012-06-13 Elizabeth C. Ferrara , Roopesh Ojha , Maria Elena Monzani , Nicola Omodei

The galactic diffuse $\gamma$-ray emission, as seen by Fermi Large Area Telescope (LAT), shows a sharp peak in the region around 4 kpc from the Galactic center, which can be interpreted either as due to an enhanced density of cosmic-ray…

High Energy Astrophysical Phenomena · Physics 2021-03-23 Giada Peron , Felix Aharonian , Sabrina Casanova , Ruizhi Yang , Roberta Zanin

Cold dark matter subhalos are expected to populate galaxies in numbers. If dark matter self-annihilates, these objects turn into prime targets for indirect searches, in particular with gamma-ray telescopes. Incidentally, the Fermi-LAT…

High Energy Astrophysical Phenomena · Physics 2022-10-31 Gaétan Facchinetti , Julien Lavalle , Martin Stref

One of the main scientific objectives of the ongoing Fermi mission is unveiling the nature of the unidentified gamma-ray sources (UGSs). Despite the large improvements of Fermi in the localization of gamma-ray sources with respect to the…

High Energy Astrophysical Phenomena · Physics 2015-06-04 F. Massaro , R. D'Abrusco , G. Tosti , M. Ajello , A. Paggi. D. Gasparrini

We have investigated a number of factors that can have significant impacts on the classification performance of $\gamma$-ray sources detected by Fermi Large Area Telescope (LAT) with machine learning techniques. We show that a framework of…

Instrumentation and Methods for Astrophysics · Physics 2020-01-29 Shengda Luo , Alex P. Leung , C. Y. Hui , K. L. Li

Excess of gamma rays with a spherical morphology around the Galactic center (GC) observed in the Fermi large area telescope (LAT) data is one of the most intriguing features in the gamma-ray sky. The excess has been interpreted by…

High Energy Astrophysical Phenomena · Physics 2024-06-07 Dmitry V. Malyshev

Observation of gamma-rays from dwarf galaxies is an effective way to search for particle dark matter. Using 4-year data of Fermi-LAT observations on a series of Milky Way satellites, we develop a general way to search for the signals from…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Yue-Lin Sming Tsai , Qiang Yuan , Xiaoyuan Huang

One of the main scientific objectives of the recent Fermi mission is investigating the origin of the unidentified gamma-ray sources (UGSs). Despite the large improvements of Fermi in the gamma-ray source localization with respect to the…

High Energy Astrophysical Phenomena · Physics 2013-03-15 F. Massaro , R. D'Abrusco , A. Paggi , N. Masetti , M. Giroletti , G. Tosti , Howard A. Smith

Several classes of astrophysical sources contribute to the approximately isotropic gamma-ray background measured by the Fermi Gamma-Ray Space Telescope. In this paper, we use Fermi's catalog of gamma-ray sources (along with corresponding…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Ilias Cholis , Dan Hooper , Samuel D. McDermott

Identifying as many gamma-ray pulsars as possible in the Fermi Large Area Telescope (LAT) data helps test pulsar emission models by comparing predicted and observed properties for a large, varied sample with as little selection bias as…

Entering a new era of high-energy gamma-ray experiments, there is an exciting quest for the first detection of gamma-ray emission from clusters of galaxies. To complement these observational efforts, we use high-resolution simulations of a…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Anders Pinzke , Christoph Pfrommer

We reconstruct the extra-galactic gamma-ray source-count distribution, or $dN/dS$, of resolved and unresolved sources by adopting machine learning techniques. Specifically, we train a convolutional neural network on synthetic 2-dimensional…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-16 Aurelio Amerio , Alessandro Cuoco , Nicolao Fornengo

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 implemented a novel technique to perform the collective spectral analysis of sets of multiple gamma-ray point sources using the data collected by the Large Area Telescope onboard the Fermi satellite. The energy spectra of the sources are…

Instrumentation and Methods for Astrophysics · Physics 2012-08-02 M. N. Mazziotta , F. Loparco , F. de Palma , N. Giglietto

Recent observations indicating the existence of a monochromatic gamma-ray line with energy ~130 GeV in the Fermi-LAT data have attracted great interest due to the possibility that the line feature stems from the annihilation of dark matter…

High Energy Astrophysical Phenomena · Physics 2013-08-28 Eric Carlson , Tim Linden , Stefano Profumo , Christoph Weniger