NUSTAR OBSERVATION OF THE MAGNETAR 1RXS J170849.0-400910

Magnetars are young isolated neutron stars with bright broadband 0.5200keV persistent Xray emission, caused by the decay of the extremely highinternal and external magnetic field. Here we propose a simultaneousNuSTAR+XMMNewton observation of one of the brightest magnetars,1RXSvirgulJ170849.0 400910. This source shows the most drastic changes in pulseprofile shape with energy as well as the most complex spectral variations withphase. The proposed observation will allow us to perform broadbandhighsensitivity fineresolution phaseresolved spectroscopy, crucial todisentangle the contribution from different spectral components in each phasebin. Such analysis would be the ultimate test for the currently available theoretical models for Xray emission production in magnetars. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]