Neutron stars multi-lambda fast variability\: probing disk-jet connection

Fast opticalinfrared photometry applied to black hole Xray binaries has nowrevealed its great potential and has shown to be one of the best ways to probethe jet in its inner most regions. Nonetheless Neutron Star Xray binaries,which are clearly dominated by the jet at IR wavelength, have not been studiedyet with such approach. Here we propose to observe the Neutron Star Low MassXray binary 4U 172834 simultaneously with XMMNewton and HAWKI@VLT. We ask toperform 6 (7 ks apiece) pointings to be matched by 6 (1 h apiece) HAWKI@VLTobservations. These data will allow us to study the discjet interaction indifferent accretion regimes and to search for, and investigate the between jetproperties in black holes and neutron stars Xray binaries. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]