Observational and theoretical constraints for an H$\alpha$-halo around the Crab Nebula

A. Tziamtzis, M. Schirmer, P. Lundqvist +1

We searched for a fast moving H$\alpha$ shell around the Crab nebula. Such a shell could account for this supernova remnant's missing mass, and carry enough kinetic energy to make SN 10…