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Open AccessJournal ArticleDOI

Fermi Large Area Telescope Measurements of the Diffuse Gamma-Ray Emission at Intermediate Galactic Latitudes

A. A. Abdo, +191 more
- 18 Dec 2009 - 
- Vol. 103, Iss: 25, pp 251101-251101
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TLDR
The Large Area Telescope (LAT) instrument on the Fermi Gamma-Ray Space Telescope has measured the diffuse gamma-ray emission with improved sensitivity and resolution compared to EGRET, and the LAT spectrum for this region of the sky is well reproduced by a diffuse galactic gamma-rays emission model that is consistent with local CR spectra and inconsistent with the EGRET GeV excess.
Abstract
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 Observatory indicated excess gamma-ray emission > 1 GeV relative to diffuse Galactic gamma-ray emission models consistent with directly measured CR spectra (the so-called ``EGRET GeV excess''). The excess emission was observed in all directions on the sky, and a variety of explanations have been proposed, including beyond-the-Standard-Model scenarios like annihilating or decaying dark matter. The Large Area Telescope (LAT) instrument on the Fermi Gamma-ray Space Telescope has measured the diffuse gamma-ray emission with improved sensitivity and resolution compared to EGRET. We report on LAT measurements of the diffuse gamma-ray emission for energies 100 MeV to 10 GeV and Galactic latitudes 10 deg. <= |b| <= 20 deg. The LAT spectrum for this region of the sky is well reproduced by a diffuse Galactic gamma-ray emission model that is consistent with local CR spectra and inconsistent with the EGRET GeV excess.

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Citations
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Journal ArticleDOI

Fermi large area telescope first source catalog

A. A. Abdo, +288 more
TL;DR: The first Fermi-LAT catalog (1FGL) as mentioned in this paper contains 1451 sources detected and characterized in the 100 MeV to 100 GeV range, and the threshold likelihood Test Statistic is 25, corresponding to a significance of just over 4 sigma.
Journal ArticleDOI

Dark matter annihilation in the Galactic Center as seen by the Fermi Gamma Ray Space Telescope

TL;DR: In this paper, the first two years of data from the Fermi Gamma Ray Space Telescope from the direction of the inner 10° around the Galactic Center with the intention of constraining, or finding evidence of, annihilating dark matter was analyzed.
Journal ArticleDOI

Fermi-LAT observations of the diffuse γ-ray emission: implications for cosmic rays and the interstellar medium

Markus Ackermann, +179 more
TL;DR: In this paper, a grid of models is created by varying within observational limits the distribution of cosmic-ray sources, the size of the cosmicray confinement volume (halo), and distribution of interstellar gas.
Journal ArticleDOI

DEVELOPMENT of the MODEL of GALACTIC INTERSTELLAR EMISSION for STANDARD POINT-SOURCE ANALYSIS of FERMI LARGE AREA TELESCOPE DATA

Fabio Acero, +169 more
TL;DR: In this article, the authors describe the development of the Galactic Interstellar Emission Model (GIEM) which is the standard adopted by the LAT Collaboration and is publicly available, based on a linear combination of maps for interstellar gas column density in Galactocentric annuli and for the inverse-Compton emission produced in the Galaxy.
Journal ArticleDOI

Constraints on Cosmic-ray Propagation Models from A Global Bayesian Analysis

TL;DR: In this article, a working method for a full Bayesian parameter estimation for a numerical cosmic ray propagation model is presented, using nested sampling and Markov Chain Monte Carlo methods (implemented in the SuperBayeS code) despite the heavy computational demands of a numerical propagation code.
References
More filters
Book

Classification and regression trees

Leo Breiman
TL;DR: The methodology used to construct tree structured rules is the focus of a monograph as mentioned in this paper, covering the use of trees as a data analysis method, and in a more mathematical framework, proving some of their fundamental properties.
Journal ArticleDOI

HEALPix: A Framework for High-Resolution Discretization and Fast Analysis of Data Distributed on the Sphere

TL;DR: This paper considers the requirements and implementation constraints on a framework that simultaneously enables an efficient discretization with associated hierarchical indexation and fast analysis/synthesis of functions defined on the sphere and demonstrates how these are explicitly satisfied by HEALPix.
Journal ArticleDOI

HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere

TL;DR: The Hierarchical Equal Area iso-Latitude Pixelization (HEALPix) as discussed by the authors is a data structure with an associated library of computational algorithms and visualization software that supports fast scientific applications executable directly on very large volumes of astronomical data and large area surveys in the form of discretized spherical maps.
Journal ArticleDOI

The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission

W. B. Atwood, +292 more
TL;DR: The Large Area Telescope (Fermi/LAT) as mentioned in this paper is the primary instrument on the Fermi Gamma-ray Space Telescope, which is an imaging, wide field-of-view, high-energy gamma-ray telescope, covering the energy range from below 20 MeV to more than 300 GeV.
Journal ArticleDOI

The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission

TL;DR: The Large Area Telescope (Fermi/LAT) as discussed by the authors is the primary instrument on the Fermi Gamma-ray Space Telescope, which is an imaging, wide field-of-view, high-energy gamma-ray telescope, covering the energy range from below 20 MeV to more than 300 GeV.
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