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The MAGIC collaboration has recently reported correlated X-ray and VHE gamma-ray emission from the gamma-ray binary LS I +61?303 during ~60% of one orbit, thus suggesting that the emission in these two bands has its origin in a single particle population. Using a one zone population of relativistic leptonic particles with dominant adiabatic losses located at the position of the compact object we are able to reproduce the observed X-ray and VHE lightcurves. From the best fit result, we obtain the magnetic field, energy budget and acceleration efficiency of the accelerator, and discuss these in the context of the young non-acretting pulsar and acretting compact object scenarios. The results also confirm that the GeV emission detected by Fermi does not come from the same parent particle population as the X-ray and VHE emission. [ABSTRACT FROM AUTHOR]

We present a model to estimate the synchrotron radio emission generated in microquasar (MQ) jets due to secondary pairs created via decay of charged pions produced in proton-proton collisions between stellar wind ions and jet relativistic protons. The synchrotron radiation produced by secondary electrons/positrons is computed using consistently derived particle energy distributions. Energy losses due to synchrotron and inverse Compton (IC) processes, and adiabatic expansion, are taken into account. The space parameter for the model is explored and the corresponding spectral energy distributions (SEDs) are presented. We conclude that secondary leptonic emission represents a significant though hardly dominant contribution to the total radio emission in MQs, with observational consequences that can be used to test some still unknown processes occurring in these objects as well as the nature of the matter outflowing in their jets. [ABSTRACT FROM AUTHOR]

LS 5039 is the only X-ray binary persistently detected at TeV energies by the Cherenkov HESS telescope. It is moreover a γ-ray emitter in the GeV and possibly MeV energy ranges. To understand important aspects of jet physics, like the magnetic field content or particle acceleration, and emission processes, such as synchrotron and inverse Compton (IC), a complete modeling of the multiwavelength data is necessary. LS 5039 has been detected along almost all the electromagnetic spectrum thanks to several radio, infrared, optical and soft X-ray detections. However, hard X-ray detections above 20 keV have been so far elusive and/or doubtful, partly due to source confusion for the poor spatial resolution of hard X-ray instruments. We report here on deep (∼300 ks) serendipitous INTEGRAL hard X-ray observations of LS 5039, coupled with simultaneous VLA radio observations. We obtain a 20-40 keV flux of 1.1±0.3 mCrab (5.9 (±1.6) ×10−12 erg cm−2 s−1), a 40-100 keV upper limit of 1.5 mCrab (9.5×10−12 erg cm−2 s−1), and typical radio flux densities of ∼25 mJy at 5 GHz. These hard X-ray fluxes are significantly lower than previous estimates obtained with BATSE in the same energy range but, in the lower interval, agree with extrapolation of previous RXTE measurements. The INTEGRAL observations also hint to a break in the spectral behavior at hard X-rays. A more sensitive characterization of the hard X-ray spectrum of LS 5039 from 20 to 100 keV could therefore constrain key aspects of the jet physics, like the relativistic particle spectrum and the magnetic field strength. Future multiwavelength observations would allow to establish whether such hard X-ray synchrotron emission is produced by the same population of relativistic electrons as those presumably producing TeV emission through IC. [ABSTRACT FROM AUTHOR]

In this work we discuss two different types of models for the high-energy gamma-ray production in microquasars. On the one hand, we introduce a new leptonic model where the emission arises from inverse Compton interactions with both internal (synchrotron) and external photon fields, and relativistic Bremsstrahlung from interactions with cold protons in the jet and the stellar wind material. On the other hand, we introduce a hadronic model where the gamma rays are the result of interactions between relativistic protons in the jet and cold protons from the anisotropic stellar wind. Spectral differences and similarities between both types of models are briefly discussed. [ABSTRACT FROM AUTHOR]