The Crab Nebula: An Astrophysical Chimera

Abstract

The Crab Nebula, henceforth the Crab, the remnant of the historical supernova of 1054 AD, has long been of intense interest. The pulsar at the center of the Crab has a spin-down luminosity ∼10 5 times that of the Sun. The outer nebula holds several solar masses of material ejected by the explosion. Between the two lies the trapped pulsar wind, visible as synchrotron radiation at radio wavelengths through X-ray wavelengths. Recent observations with the Hubble Space Telescope, the Chandra X-ray Observatory, and a host of other instruments have provided a wealth of information about the extraordinary structure and dynamics of the Crab. Understanding those data requires thinking of the Crab not in terms of its individual components, but instead as a single interconnected physical system formed as the axisymmetrical wind from the pulsar pushes its way outward through a larger freely expanding supernova remnant.

Evidence for Magnetar Formation in Broad-lined Type Ic Supernovae1998bw and 2002ap

“…From Table 1 we see a large difference of κ γ,mag between SNe 1998bw and 2002ap. Inspection of Figure 8 of Kotera et al (2013) indicates that this could imply average magnetar photon energies ∼ 10 − 100 keV, in agreement with observation (Hester 2008). Theoretically, magnetar radiation depends on several parameters, e.g., magnetic field, rotation period, angle between rotation axis and magnetic axis, and theorists are still struggling to unequivocally predict its spectrum energy distribution (Kennel & Coroniti 1984a,b;Lyubarsky & Kirk 2001;Wang & Dai 2013;Kargaltsev et al 2015;Murase et al 2015;Wang et al 2015aWang et al , 2016aLiu et al 2016a).…”

Galactic evolution of rapid neutron capture process abundances: the inhomogeneous approach

“…In their hydrostatic burning phase, these stars lock-up a part of the overall mass and return most of it to the ISM in their AGB phase by stellar winds. Since the maximum radius of these winds is orders of magnitude smaller than the output range of supernova events (e.g., radius of Crab remnant: 5.5 Ly (Hester 2008), while the diameter of the Cat's Eye Nebula is only 0.2 Ly (Reed et al 1999)), our simulation assumes that stellar winds influence the ISM only in the local calculation cell. AGB stars provide only a marginal s-process contribution to typical r-process elements like Eu (e.g., Travaglio et al 1999).…”

Pulsar-Wind Nebulae

“…The Crab nebula has been studied with nearly all major telescopes since its discovery (see Hester 2008 and references therein). However, it was not until the Hubble Space Telescope (HST; Hester et al 1995) and Chandra (Weisskopf et al 2000) era when the intricate and complex structure of the nebula was revealed (see Figure 1 for the feature nomenclature introduced by Hester et al 1995).…”