Towards an assumption-free reconstruction of the Crab Nebula 3D structure.

Thomas Martin ( Université Laval )

Our first reconstruction of the 3D structure of the Crab Nebula based on the data obtained with SITELLE (Martin et al. 2021) was assuming a homologous expansion of the remnant since 1054 C.E. Even if some data (Bienholtz et al. 2015) suggested that the expansion was accelerated near the center of the remnant, a precise knowledge of its effect on the filamentary complex was lacking. We have thus used images obtained at CFHT with MEGACAM in 2007, 2016 and 2019 to realize a complete mapping of the proper motion of the nebula in the celestial plane and reveal the important inhomogeneities of the expansion which proved to be strongly accelerated at the edge of the pulsar wind. We will also describe the next step in our reconstruction (and the first work of this kind) based on the comparison of the SITELLE spectral cube obtained in 2016 with a cube obtained this year. The expansion of the remnant between both dates will enable a measurement of the exact kinematic in 3D without relying on the homologous expansion hypothesis.