The AGASA/SUGAR Anisotropies and TeV Gamma Rays from the Galactic Center: A Possible Signature of Extremely High-energy Neutrons

Abstract

Recent analysis of data sets from two extensive air shower cosmic ray detectors shows tantalizing evidence of an anisotropic overabundance of cosmic rays towards the Galactic Center (GC) that ``turns on'' around $10^{18}$ eV. We demonstrate that the anisotropy could be due to neutrons created at the Galactic Center through charge-exchange in proton-proton collisions, where the incident, high energy protons obey an $\sim E^{-2}$ power law associated with acceleration at a strong shock. We show that the normalization supplied by the gamma-ray signal from EGRET GC source 3EG J1746-2851 -- ascribed to pp induced neutral pion decay at GeV energies -- together with a very reasonable spectral index of 2.2, predicts a neutron flux at $\sim 10^{18}$ eV fully consistent with the extremely high energy cosmic ray data. Likewise, the normalization supplied by the very recent GC data from the HESS air-Cerenkov telescope at TeV energies is almost equally-well compatible with the $\sim 10^{18}$ eV cosmic ray data. Interestingly, however, the EGRET and HESS data appear to be themselves incompatible. We consider the implications of this discrepancy. We discuss why the Galactic Center environment can allow diffusive shock acceleration at strong shocks up to energies approaching the ankle in the cosmic ray spectrum. Finally, we argue that the shock acceleration may be occuring in the shell of Sagittarius A East, an unusual supernova remnant located very close to the Galactic Center. If this connection between the anisotropy and Sagittarius A East could be firmly established it would be the first direct evidence for a particular Galactic source of cosmic rays up to energies near the ankle.

arXiv comment57 pages, 2 figures

References in corpus (34)

• The First Measurement of Spectral Lines in a Short-Period Star Bound to the Galaxy's Central Black Hole: A Paradox of Youth
• Near-infrared flares from accreting gas around the supermassive black hole at the Galactic Centre
• The Supermassive Black Hole at the Galactic Center
• Very high energy gamma rays from the direction of Sagittarius A*
• The Status of the H.E.S.S. Project
• Calibration of cameras of the H.E.S.S. detector
• Cosmic Rays, Radio Halos and Non-Thermal X-ray Emission in Clusters of Galaxies
• Radio to Gamma-Ray Emission from Shell-type Supernova Remnants: Predictions from Non-linear Shock Acceleration Models
• A Chandra Study of Sgr A East: A Supernova Remnant Regulating The Activity Of Our Galactic Center?
• Detection of Sub-TeV Gamma-Rays from the Galactic Center Direction by CANGAROO-II
• TeV Gamma-Ray Observations of the Galactic Center
• The Anisotropy of Cosmic Ray Arrival Directions around 10${}^{18}$eV
• The Anisotropy of Cosmic Ray Arrival Direction around 10^18eV
• Galactic Point Sources of TeV Antineutrinos
• Neutrino, Neutron, and Cosmic Ray Production in the External Shock Model of Gamma Ray Bursts
• Possible High-energy neutrinos from the cosmic accelerator RXJ1713.7-3946
• On photohadronic processes in astrophysical environments
• Southern Hemisphere Observations of a $10^{18}$eV Cosmic Ray Source Near the Direction of the Galactic Centre
• Three New Supernova Remnant OH Masers Near the Galactic Center: Evidence for Large Scale Maser Emission from Supernova Remnants
• Quasi-Thick Codimension 2 Braneworld
• A Kinship between the EGRET SNR's and Sgr A East
• A search for TeV gamma-ray emission from SNRs, pulsars and unidentified GeV sources in the Galactic plane in the longitude range between -2 deg and 85 deg
• Discovering Long Wavelength Neutrino Oscillations in the Distorted Neutrino Spectrum of Galactic Supernova Remnants
• Have Atmospheric Cerenkov Telescopes Observed Dark Matter?
• On the Nature of the EGRET Source at the Galactic Center
• Oscillating Neutrinos from the Galactic Center
• Cosmic ray photodisintegration and the knee of the spectrum
• The last Gamma Ray Burst in our Galaxy? On the observed cosmic ray excess at particle energy 1 EeV
• Inelasticity in p-nucleus collisions and its application to high energy cosmic-ray cascades
• Cosmic ray drift, the second knee and galactic anisotropies
• A Self-Consistent Model for the Broad-band Spectrum of Sgr A East at the Galactic Center
• Decaying neutron propagation in the Galaxy and the Cosmic Ray anisotropy at 1 EeV
• Images of very high energy cosmic ray sources in the Galaxy: I. A source towards the Galactic Centre
• Electron Positron Annihilation Radiation from SgrA East at the Galactic Center

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• H.E.S.S. observations of the Galactic Center region and their possible dark matter interpretation
• Observation of Gamma Rays from the Galactic Center with the MAGIC Telescope
• Disrupted Globular Clusters Can Explain the Galactic Center Gamma Ray Excess
• Fitting the Gamma-Ray Spectrum from Dark Matter with DMFIT: GLAST and the Galactic Center Region
• Radio, X-ray, and gamma-ray Emission Models of the Colliding Winds Binary WR 140
• Potential Neutrino Signals from Galactic Gamma-Ray Sources
• Spectrum and variability of the Galactic Center VHE gamma-ray source HESS J1745-290
• A Search for Point Sources of EeV Neutrons
• Inverse Compton Scenarios for the TeV Gamma-Ray Emission of the Galactic Centre
• Measuring the 13-mixing angle and the CP phase with neutrino telescopes
• Localising the VHE gamma-ray source at the Galactic Centre
• Annihilation Emission from the Galactic Black Hole
• A Persistent High-Energy Flux from the Heart of the Milky Way : Integral's view of the Galactic Center
• Anisotropy studies around the galactic centre at EeV energies with the Auger Observatory
• Stochastic Acceleration in the Galactic Center HESS Source
• Cosmic Rays: The Second Knee and Beyond
• Towards Determination of the Initial Flavor Composition of Ultrahigh-energy Neutrino Fluxes with Neutrino Telescopes
• TeV gamma-rays and neutrinos from photo-disintegration of nuclei in Cygnus OB2
• Enhanced Cosmic Ray Flux and Ionization for Star Formation in Molecular Clouds Interacting with Supernova Remnants
• Non-thermal Processes in Black-Hole-Jet Magnetospheres
• Pulsar Wind Nebulae and the Non-thermal X-Ray Emission of Millisecond Pulsars
• A search for point sources of EeV photons
• Spectral Study of the HESS J1745-290 Gamma-Ray Source as Dark Matter Signal
• Simultaneous H.E.S.S. and Chandra observations of Sagittarius A* during an X-ray flare
• Multi-Messenger Physics with the Pierre Auger Observatory
• Gamma rays from the Galactic Centre region: a review
• A targeted search for point sources of EeV photons with the Pierre Auger Observatory
• A Possible Link Between the Galactic Center HESS Source and Sgr A*
• Ultra-High-Energy Cosmic Rays from the Radio Lobes of AGNs
• Diffuse TeV Emission at the Galactic Centre
• TeV Neutrinos from SuperNova Remnants embedded in Giant Molecular Clouds
• The Cosmic Ray Distribution in Sagittarius B
• Sgr A East as a possible high energy neutron factory in the Galactic Centre
• Disformal scalars as dark matter candidates: Branon phenomenology
• Capture of a Red Giant by the Black Hole Sagittarius A* as a Possible Origin for the TeV Gamma Rays from the Galactic Center
• Neutrino fluxes from Dark Matter in the HESS J1745-290 source at the Galactic Center
• Diffusive Cosmic Ray Acceleration at the Galactic Centre
• Antiproton signatures from astrophysical and dark matter sources at the galactic center
• The Gamma-ray Afterglows of Tidal Disruption Events
• Fermi LAT observations of Sagittarius A*: Imaging Analysis
• Detectable neutrino fluxes due to enhanced cosmic ray densities in the Galactic Center region
• Primary Versus Secondary Leptons in the EGRET SNR's
• PeV Gamma Rays from Interactions of Ultra High Energy Cosmic Rays in the Milky Way
• The Broadband Spectrum of Galaxy Clusters
• A further study of μ-τsymmetry breaking at neutrino telescopes after the Daya Bay and RENO measurements of θ_{13}
• Neutrinos and Gamma Rays from Galaxy Clusters
• Modelling the time dependence of the TeV Gamma-ray source at the Galactic Centre
• Assessing the Feasibility of Cosmic-Ray Acceleration by Magnetic Turbulence at the Galactic Center
• Astrophysics in 2005
• Search for Sources of High Energy Neutrons with Four Years of Data from the IceTop Detector
• Radio Synchrotron Emission from Secondary Leptons in the Vicinity of Sgr A*
• High-(Energy)-Lights -- The Very High Energy Gamma-Ray Sky
• The H.E.S.S. View of the Central 200 Parsecs
• Astronomy with ultra high-energy particles
• High Energy Activity of the Super-Massive Black Hole at the Galactic Center
• Probing New Physics with Astrophysical Neutrinos
• The Neutron as an Alternative Explanation for the Trans GZK Cosmic Rays
• Anisotropy studies around the galactic center