Fabio

Despite being one of the prototype of Galactic cosmic ray accelerator, important parameters such as age, shock speed, ambient medium density and progenitor properties are still poorly known for the SNR RX J1713.7−3946. In particular, determining the ambient density is crucial to understand the nature of the gamma-ray emission and constrain the fraction of kinetic energy transferred to hadrons accelerated at the shock front of the SNR.
For over a decade, thermal X-ray emission, which could constrain the ambient density, has been searched for in this synchrotron dominated SNR. Deep XMM-Newton and Suzaku observations have finally revealed this emission and it’s nature will be discussed (ejecta or shocked ISM). Another possibility to constrain the ambient density medium is through X-ray proper motion measurements. The South-East region of the SNR present the best example of clear and sharp X-ray filaments and the shock in this region is probably expanding in the low density carved by the strong winds of the progenitor. Using follow-up XMM observations of the South-East region and 13 years of leverage, we will present the first clear measurement of proper motion in RX J1713.7−3946 and the implication in terms of ambient density, shock speed, and age of the SNR.