Supernova Remnants: An Odyssey in Space after Stellar death

Supernova Remnants: An Odyssey in Space after Stellar death

Supernova Remnants: An Odyssey in Space after Stellar death


1st Abstract

Title (1st Abstract)

New Radio and Optical Expansion Rate Measurements of the Crab Nebula

First Author

Michael F. Bietenholz


Hartebeesthoek Radio Astronomy Observatory, Krugersdorp, 1740, South Africa

Additional Authors

Richard L. Nugent (IOTA, International Occultation Timing Association, Houston, TX 77219, USA)

Presentation options



3. Pulsar winds nebulae (including Crab flares)

1st Abstract

We present new JVLA radio observations of the Crab nebula, which we use, along with older observations taken over a ~30-yr period, to determined the expansion rate of the synchrotron nebula. We find a convergence date for the radio synchrotron nebula of AD 1255 +- 27. We also re-evaluated the expansion rate of the optical line emitting filaments, and we show that the traditional estimates of their convergence date are slightly biased. We find an un-biased convergence date of AD 1091 +- 34, ~40 yr earlier than previous estimates. Our results show that both the synchrotron nebula and the optical line-emitting filaments have been accelerated since the explosion in AD 1054, but former more strongly than the latter. This finding supports the picture that the filaments are the result of the Rayleigh-Taylor instability at the interface between the pulsar-wind nebula and the surrounding freely-expanding supernova ejecta, and rules out models where the pulsar wind bubble is interacting directly with the pre-supernova wind of the Crab’s progenitor. Our new observations were taken ~2 months after the gamma-ray flare of 2012 July, and also allow us to put a sensitive limit on any radio emission associated with the flare of <0.0002 times the radio luminosity that of the nebula.