Title: The first ever 3D velocity map of the Crab Nebula obtained with SITELLE reveals its origin.
Presenter: Thomas Martin
Abstract:
Being one of the most famous remnant of a core-collapse supernova (CCSN), the Crab Nebula is yet an atypical one and its origin remains a long-standing debate. On the one hand, Chinese historical records indicate that its explosion in 1054 CE was visible to the naked eye during at least 3 weeks making it a very bright event which can naturally be explained by a typical high energy supernova (SN) explosion of a star with a mass higher than 10.5 Msol, while, on the other hand, the kinetic energy of the remnant visible today is 10 times lower than the typical energy released by such luminous events (10^51 erg). This low kinetic energy could however be explained by the explosion of a lower mass progenitor although an alternative mechanism should be invoked to make it visible in 1054 CE. Plausible scenarios involving a low-mass progenitor exploding into a small and dense shell of circumstellar material released by the star before the explosion have emerged in the last decade (Woosley & Heger 2015) but a compelling evidence of circumstellar material (CSM) interaction is still lacking. Working with two hyperspectral cubes obtained with SITELLE six years apart (2016 - 2022) to measure the proper motion and radial velocity of every emission element, we have obtained the first complete 3D velocity map of the Crab. Based on this unique dataset, a detailed study of the remnant kinematics has revealed the presence of decelerated material which can only be explained by the presence of strong CSM interaction, strongly advocating for scenarios involving pre-existing CSM to explain the origin and the present state of the Crab Nebula.