Del Palacio, S.García, F.Altamirano, DiegoBarbá, R. H.Bosch i Ramon, ValentíCorcoran, Michael F.De Becker, M.Hamaguchi, K.Maíz Apellániz, J.Munar i Adrover, PereParedes i Poy, Josep MariaRomero, Gustavo E.Sana, HuguesTavani, M.Ud-Doula, A.2020-05-252020-05-252020-05-010035-8711https://hdl.handle.net/2445/162273We conducted an observational campaign towards one of the most massive and luminous colliding wind binaries in the Galaxy, HD~93129A, close to its periastron passage in 2018. During this time the source was predicted to be in its maximum of high-energy emission. Here we present our data analysis from the X-ray satellites \textit{Chandra} and \textit{NuSTAR} and the γ-ray satellite \textit{AGILE}. High-energy emission coincident with HD~93129A was detected in the X-ray band up to ∼18~keV, whereas in the γ-ray band only upper limits were obtained. We interpret the derived fluxes using a non-thermal radiative model for the wind-collision region. We establish a conservative upper limit for the fraction of the wind kinetic power that is converted into relativistic electron acceleration, fNT,e<0.02. In addition, we set a lower limit for the magnetic field in the wind-collision region as BWCR>0.3~G. We also argue a putative interpretation of the emission from which we estimate fNT,e≈0.006 and BWCR≈0.5~G. We conclude that multi-wavelength, dedicated observing campaigns during carefully selected epochs are a powerful tool for characterising the relativistic particle content and magnetic field intensity in colliding wind binaries.10 p.application/pdfeng(c) Del Palacio, S. et al., 2020Acceleradors de partículesEstels binaris de raigs XRaigs gammaParticle acceleratorsX-ray binariesGamma raysinfo:eu-repo/semantics/article7010552020-05-25info:eu-repo/semantics/openAccess