Diffuse Galactic Gamma Rays at intermediate and high latitudes. I. Constraints on the ISM properties

Abstract

We study the high latitude (|b|>10) diffuse gamma-ray emission in the Galaxy in light of the recently published data from the Fermi collaboration at energies between 100 MeV and 100 GeV. The unprecedented accuracy in these measurements allows to probe and constrain the properties of sources and propagation of cosmic rays (CRs) in the Galaxy, as well as confirming conventional assumptions made on the interstellar medium (ISM). Using the publicly available DRAGON code, that has been shown to reproduce local measurements of CRs, we study assumptions made in the literature on HI and H2 gas distributions in the ISM, and non spatially uniform models of diffusion in the Galaxy. By performing a combined analysis of CR and gamma-ray spectra, we derive constraints on the properties of the ISM gas distribution and the vertical scale height of galactic CR diffusion, which may have implications also on indirect Dark Matter detection. We also discuss some of the possible interpretations of the break at ~230 GV in CR protons and helium spectra, recently observed by PAMELA and their impact on gamma-rays.

28 pages, 18 figures, 2 Tables. changes in v2: added 2 appendices, 1 table and 4 figures, small revision in text, results and conclusions unchanged

References in corpus (39)

• PYTHIA 6.4 Physics and Manual
• Observation of an anomalous positron abundance in the cosmic radiation
• Giant Gamma-ray Bubbles from Fermi-LAT: AGN Activity or Bipolar Galactic Wind?
• PAMELA Measurements of Cosmic-ray Proton and Helium Spectra
• Dark Matter Annihilation in The Galactic Center As Seen by the Fermi Gamma Ray Space Telescope
• The Spectrum of the Isotropic Diffuse Gamma-Ray Emission Derived From First-Year Fermi Large Area Telescope Data
• PAMELA - A Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics
• Radio observational constraints on Galactic 3D-emission models
• Parameterization of Gamma, e^+/- and Neutrino Spectra Produced by p-p Interaction in Astronomical Environment
• The cosmic-ray electron flux measured by the PAMELA experiment between 1 and 625 GeV
• Fermi LAT observations of cosmic-ray electrons from 7 GeV to 1 TeV
• Cosmic-Ray Proton and Helium Spectra from the First CREAM Flight
• Primary particle acceleration above 100 TeV in the shell-type Supernova Remnant RX J1713.7-3946 with deep H.E.S.S. observations
• On possible interpretations of the high energy electron-positron spectrum measured by the Fermi Large Area Telescope
• The Fermi Bubbles: Giant, Multi-Billion-Year-Old Reservoirs of Galactic Center Cosmic Rays
• Separation of anomalous and synchrotron emissions using WMAP polarization data
• Measurements of cosmic-ray secondary nuclei at high energies with the first flight of the CREAM balloon-borne experiment
• Measurements of 0.2 to 20 GeV/n cosmic-ray proton and helium spectra from 1997 through 2002 with the BESS spectrometer
• Pulsars versus Dark Matter Interpretation of ATIC/PAMELA
• A Dynamical Model for the Evolution of a Pulsar Wind Nebula inside a Non-Radiative Supernova Remnant
• Pre-launch estimates for GLAST sensitivity to Dark Matter annihilation signals
• Planck early results. XXI. Properties of the interstellar medium in the Galactic plane
• Fermi gamma-ray `bubbles' from stochastic acceleration of electrons
• The maximum momentum of particles accelerated at cosmic ray modified shocks
• Discriminating different scenarios to account for the cosmic $e^{\pm }$ excess by synchrotron and inverse Compton radiation
• Dark matter and pulsar signals for Fermi LAT, PAMELA, ATIC, HESS and WMAP data
• Constraining models of the large scale Galactic magnetic field with WMAP5 polarization data and extragalactic Rotation Measure sources
• Non-linear diffusive acceleration of heavy nuclei in supernova remnant shocks
• Implications of the Cosmic Ray Electron Spectrum and Anisotropy measured with Fermi-LAT
• Probing Gravitino Dark Matter with PAMELA and Fermi
• p, He, and C to Fe cosmic-ray primary fluxes in diffusion models: Source and transport signatures on fluxes and ratios
• Anisotropies in the gamma-ray sky from millisecond pulsars
• Understanding hadronic gamma-ray emission from supernova remnants
• Light Higgs Boson, Light Dark Matter and Gamma Rays
• The Fermi Gamma-Ray Haze from Dark Matter Annihilations and Anisotropic Diffusion
• The GeV-TeV Galactic gamma-ray diffuse emission I. Uncertainties in the predictions of the hadronic component
• "Discrepant hardenings" in cosmic ray spectra: a first estimate of the effects on secondary antiproton and diffuse gamma-ray yields
• Measuring interstellar magnetic fields by radio synchrotron emission
• Properties of Bulgeless Disk Galaxies. I. Atomic Gas

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• Cosmic Ray Electrons, Positrons and the Synchrotron emission of the Galaxy: consistent analysis and implications
• Indirect Detection Analysis: Wino Dark Matter Case Study
• Extracting limits on Dark Matter annihilation from gamma-ray observations towards dwarf spheroidal galaxies
• Characterization of Dark-Matter-induced anisotropies in the diffuse gamma-ray background
• Bremsstrahlung gamma rays from light Dark Matter
• Searching for the continuum spectrum photons correlated to the 130 GeV gamma-ray line
• Millicharged Cosmic Rays and Low Recoil Detectors
• Constraints on dark matter annihilations from diffuse gamma-ray emission in the Galaxy
• From gamma ray line signals of dark matter to the LHC
• Diffuse Galactic Gamma Rays from Shock-Accelerated Cosmic Rays
• Constraining the halo size from possible density profiles of hydrogen gas of Milky Way Galaxy
• Positron Excess from Cosmic Ray Interactions in Galactic Molecular Clouds