Astronomy and Astrophysics – Astrophysics – High Energy Astrophysical Phenomena
Scientific paper
2009-12-07
Astronomy and Astrophysics
Astrophysics
High Energy Astrophysical Phenomena
ApJ Letters, in press, revised version
Scientific paper
Fermi measurements of the high-latitude gamma-ray background strongly constrain a decaying-dark-matter origin for the 1--100 GeV Galactic positron anomaly measured with PAMELA. Inverse-Compton scattering of the microwave background by the emergent positrons produces a bump in the diffuse 100-200 MeV gamma-ray background that would protrude from the observed background at these energies. The positrons are thus constrained to emerge from the decay process at a typical energy between ~100 GeV and ~250 GeV. By considering only gamma-ray emission of the excess positrons and electrons, we derive a minimum diffuse gamma-ray flux that, apart from the positron spectrum assumed, is independent of the actual decay modes. Any gamma-rays produced directly by the dark-matter decay leads to an additional signal that make the observational limits more severe. A similar constraint on the energy of emergent positrons from annihilation in dark-matter substructures is argued to exist, according to recent estimates of enhancement in low-mass dark-matter substructures, and improved simulations of such substructure will further sharpen this constraint.
Eichler David
Pohl Martin
No associations
LandOfFree
Fermi Constrains Dark Matter Origin of High Energy Positron Anomaly does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Fermi Constrains Dark Matter Origin of High Energy Positron Anomaly, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fermi Constrains Dark Matter Origin of High Energy Positron Anomaly will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-243018