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The excesses of the cosmic positron fraction recently measured by PAMELA and the electron spectra by ATIC, PPB-BETS, Fermi and H.E.S.S. indicate the existence of primary electron and positron sources. The possible explanations include dark matter annihilation, decay, and astrophysical origin, like pulsars. In this work we show that these three scenarios can all explain the experimental results of the cosmic $e^pm$ excess. However, it may be difficult to discriminate these different scenarios by the local measurements of electrons and positrons. We propose possible discriminations among these scenarios through the synchrotron and inverse Compton radiation of the primary electrons/positrons from the region close to the Galactic center. Taking typical configurations, we find the three scenarios predict quite different spectra and skymaps of the synchrotron and inverse Compton radiation, though there are relatively large uncertainties. The most prominent differences come from the energy band $10^4sim 10^9$ MHz for synchrotron emission and $gtrsim 10$ GeV for inverse Compton emission. It might be able to discriminate at least the annihilating dark matter scenario from the other two given the high precision synchrotron and diffuse $gamma$-ray skymaps in the future.
We present multi-wavelength observations of a typical long duration GRB 120326A at $z=1.798$, including rapid observations using a submillimeter array (SMA), and a comprehensive monitoring in X-ray and optical. The SMA observation provided the fastes
Via a Bayesian likelihood analysis using 219 recent cosmic ray spectral data points we extract the anomalous part of the cosmic $e^pm$ flux. First we show that a significant tension exists between the $e^pm$ related and the rest of the fluxes. Interp
Electromagnetic observations have provided strong evidence for the existence of massive black holes in the center of galaxies, but their origin is still poorly known. Different scenarios for the formation and evolution of massive black holes lead to
First results are presented from kinetic numerical simulations of relativistic collisionless magnetic reconnection in pair plasma that include radiation reaction from both synchrotron and inverse Compton (IC) processes, motivated by non-thermal high-
We present a complete set of diagnostic tools aimed at reproducing synthetic non-thermal (synchrotron and/or Inverse Compton, IC) emissivity, integrated flux energy, polarization and spectral index simulated maps in comparison to observations. The ti