New expansion rate measurements of the Crab nebula in radio and optical

作者：Bietenholz M F; Nugent R L

来源：Monthly Notices of the Royal Astronomical Society, 2015, 454(3): 2416-2422.

DOI：10.1093/mnras/stv2112

• ISM: supernova remnants

We present new radio measurements of the expansion rate of the Crab nebula's synchrotron nebula over a similar to 30-yr period. We find a convergence date for the radio synchrotron nebula of CE 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. Using an unbiased Bayesian analysis, we find a convergence date for the filaments of CE 1091 +/- 34 (similar to 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 CE 1054, but that the synchrotron nebula has been relatively strongly accelerated, while the optical filaments have been only slightly accelerated. The finding that the synchrotron emission expands more rapidly than the filaments supports the picture that the latter 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.

• 出版日期2015-12-11