Probing the Highest Energy Phenomena of Eta Carinae around Periastron in 2014

Eta Carinae is an extremely massive binary system whose strong winds produce avariety of highenergy Xray and possibly gammaray emission. Earlierobservations found interesting features in the extremely hard Xray band: i) aflat spectral component above 9 keV toward the flux maximum; ii) strong 1520keV emission during an occultation of the windwind colliding plasma; iii)stable powerlaw emission above 25 keV. These features are signs of the highestenergy processes yet detected in any colliding wind binary. Broad band Xrayobservations around periastron are essential to understand those features. Wetherefore propose joint XMMNewton and NuSTAR observations at 4 key phasesaround the next periastron passage of Eta Carinae in 2014.6. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]