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The Fermi Gamma-ray Space Telescope has been detecting a wealth of sources where the multi-wavelength counterpart is either inconclusive or missing altogether. We present a combination of factors that can be used to identify…

High Energy Astrophysical Phenomena · Physics 2015-06-17 F. Acero , D. Donato , R. Ojha , J. Stevens , P. G. Edwards , E. Ferrara , J. Blanchard , J. E. J. Lovell , D. J. Thompson

We present a new method to interpret the $\gamma$-ray data of our inner Galaxy as measured by the Fermi Large Area Telescope (Fermi LAT). We train and test convolutional neural networks with simulated Fermi-LAT images based on models tuned…

High Energy Astrophysical Phenomena · Physics 2018-05-29 Sascha Caron , Germán A. Gómez-Vargas , Luc Hendriks , Roberto Ruiz de Austri

A novel application of machine-learning (ML) based image processing algorithms is proposed to analyze an all-sky map (ASM) obtained using the Fermi Gamma-ray Space Telescope. An attempt was made to simulate a one-year ASM from a…

High Energy Astrophysical Phenomena · Physics 2021-06-02 Shogo Sato , Jun Kataoka , Soichiro Ito , Jun'ichi Kotoku , Masato Taki , Asuka Oyama , Takaya Toyoda , Yuki Nakamura , Marino Yamamoto

We present evidence for $\gamma$-ray emission from a stacked population of 39 high-latitude globular clusters (GCs) not detected in the Fermi Point Source Catalog, likely attributable to populations of millisecond pulsars within them. In…

High Energy Astrophysical Phenomena · Physics 2024-10-17 Owen K. Henry , Timothy A. D. Paglione , Yuzhe Song , Joshua Tan , David Zurek , Vanessa Pinto

Clusters of galaxies are the largest gravitationally-bound systems in the Universe. Their dynamics are dominated by dark matter (DM), which makes them among the best targets for indirect DM searches. We analyze 12 years of data collected by…

High Energy Astrophysical Phenomena · Physics 2023-05-03 Mattia Di Mauro , Judit Pérez-Romero , Miguel A. Sánchez-Conde , Nicolao Fornengo

Photons produced in the annihilations of dark matter particles can be detected by gamma-ray telescopes; this technique of indirect detection serves as a cornerstone of the upcoming assault on the dark matter paradigm. The main obstacle to…

Cosmology and Nongalactic Astrophysics · Physics 2011-07-08 Eric J. Baxter , Scott Dodelson

We present an algorithm capable of detecting diffuse, dim sources of any size in an astronomical image. These sources often defeat traditional methods for source finding, which expand regions around points of high intensity. Extended…

Instrumentation and Methods for Astrophysics · Physics 2016-01-05 T. Butler-Yeoman , M. Frean , C. P. Hollitt , D. W. Hogg , M. Johnston-Hollitt

We developed a source detection algorithm based on the Minimal Spanning Tree (MST), that is a graph-theoretical method useful for finding clusters in a given set of points. This algorithm is applied to gamma-ray bidimensional images where…

Astrophysics · Physics 2008-11-26 Riccardo Campana , Enrico Massaro , Dario Gasparrini , Sara Cutini , Andrea Tramacere

Nearly one-third of the gamma-ray sources detected by Fermi are still unidentified, despite significant recent progress in this effort. On the other hand, all the gamma-ray extragalactic sources associated in the second Fermi-LAT catalog…

High Energy Astrophysical Phenomena · Physics 2019-08-19 F. Massaro , R. D'Abrusco , A. Paggi , N. Masetti , M. Giroletti , G. Tosti , Howard A. Smith , S. Funk

We study the potential of weak lensing surveys to detect clusters of galaxies, using a fast Particle Mesh cosmological N-body simulation algorithm specifically tailored to investigate the statistics of these mass-selected clusters. In…

Astrophysics · Physics 2009-11-10 Joseph F. Hennawi , David N. Spergel

Because of the relatively broad angular resolution of current gamma-ray instruments in the MeV-GeV energy range, the photons of a given source are mixed with those coming from nearby sources or diffuse background. This source confusion…

Instrumentation and Methods for Astrophysics · Physics 2019-02-06 P. Bruel

The Large Area Telescope (LAT) onboard the Fermi satellite is exploring the gamma-ray sky in the energy range above 20MeV. We have developed a method to reconstruct the energy spectra of the gamma rays detected by the Fermi LAT instrument…

Instrumentation and Methods for Astrophysics · Physics 2019-08-14 M. N. Mazziotta

Around one third of the point-like sources in the Fermi-LAT catalogs remain as unidentified sources (unIDs) today. Indeed, these unIDs lack a clear, univocal association with a known astrophysical source. If dark matter (DM) is composed of…

High Energy Astrophysical Phenomena · Physics 2023-02-21 V. Gammaldi , B. Zaldívar , M. A. Sánchez-Conde , J. Coronado-Blázquez

The Fermi Gamma-Ray Space Telescope has discovered many gamma-ray pulsars, both as radio-loud objects and radio-quiet or radio-weak pulsars that have been identified through blind period searches. The latter presumably have gamma-ray beams…

High Energy Astrophysical Phenomena · Physics 2010-02-02 Marco Pierbattista , Isabelle Grenier , Alice Harding , Peter Gonthier

Revealing the nature of unassociated high-energy (> 100 MeV) gamma-ray sources remains a challenge 35 years after their discovery. Of the 934 gamma-ray sources at high Galactic latitude (|b| > 15 degrees) in the First Fermi-LAT catalogue…

High Energy Astrophysical Phenomena · Physics 2010-11-25 N. Mirabal , D. Nieto , S. Pardo

Over 2000 Gamma ray sources identified by the Large Area Telescope (LAT) on NASA's Fermi Gamma-ray Space Telescope are considered unassociated, meaning that they have no known counterparts in any other frequency regime. We have carried out…

The source-count distribution as a function of their flux, dN/dS, is one of the main quantities characterizing gamma-ray source populations. We employ statistical properties of the Fermi Large Area Telescope (LAT) photon counts map to…

High Energy Astrophysical Phenomena · Physics 2016-07-28 Hannes-S. Zechlin , Alessandro Cuoco , Fiorenza Donato , Nicolao Fornengo , Andrea Vittino

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

We apply a number of statistical and machine learning techniques to classify and rank gamma-ray sources from the Third Fermi Large Area Telescope (LAT) Source Catalog (3FGL), according to their likelihood of falling into the two major…

High Energy Astrophysical Phenomena · Physics 2016-03-23 P. M. Saz Parkinson , H. Xu , P. L. H. Yu , D. Salvetti , M. Marelli , A. D. Falcone

Classification of sources is one of the most important tasks in astronomy. Sources detected in one wavelength band, for example using gamma rays, may have several possible associations in other wavebands, or there may be no plausible…

High Energy Astrophysical Phenomena · Physics 2022-04-19 Aakash Bhat , Dmitry Malyshev