07 February 2002 CfA Colloquium


Title: The Crab Nebula: The Gift that Keeps on Giving

Speaker: Jeff Hester

Abstract:

In many ways the Crab Nebula is the object that started off the study of supernova remnants, yet hundreds of years after its discovery it is still poorly understood in many respects. Recently, a number of observations and theoretical results have shed new light on longstanding questions and misconceptions about the Crab. We are taught in graduate school that the Crab is a freely expanding ejecta-dominated remnant, with the slight added complication that it contains a pulsar and synchrotron nebula. This conception of the Crab is incorrect. Instead, when we think of the Crab we should think first of the powerful and dynamic axisymmetric wind from an energetic pulsar as it powers a high pressure synchrotron nebula. That synchrotron nebula is sweeping up and concentrating thermal ejecta into dense, complex Rayleigh-Taylor filaments as it pushes its way out through a large, freely expanding remnant. This larger remnant is all but unseen, but probably carries the bulk of the mass and kinetic energy from the explosion. Every aspect of the visible Crab - from its overall size and shape, to the complex structure of its filaments, to the highly dynamical structure at its heart - is a direct result of the action of the wind from the Crab pulsar.

References for students:

Bietenholz, M. F., Frail, D. A., & Hester, J. J. 2001 ApJ, 560, 254 ADS link

Hester, J. J. 1998, MmSAI, 69, 883 ADS link

Sankrit, R. et al. 1998, ApJ, 504, 344 ADS link

Hester, J. J. et al. 1995, ApJ, 448, 240 ADS link